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Problem Statement: RGibbs in the model may make simulation slower than expected. What are the reasons behind these?
Description: RGibbs is the only reactor block where you do not require reaction stichometry. Without such detail reaction data, RGibbs can determine phase equilibrium by minimizing Gibbs free energy, subject to atom balance constraints at given process condition (T,P or P,H). For example, when you model a burner, which is fundamentally a reactor but you perhaps don't know details of what is happening inside, RGibbs may be the one to use. However, use of RGIBBS makes the model considerably slower in response to change to feed flow rate and/ or process variables. | Solution: 1) In Dynamics RGIBSS can be modeled as Instaneous or PFR. PFR-RGibbs additionally calculates response-delay and equipment-volume for given geometry data. It is a minimum effort to take account the holdup contribution, but it is not done in rigorous way. It is not recommended PFR configuration in RGibbs since it doesn't look theoretically sound. When a holdup is considered for RGibbs, it perhaps better to combine an Instantaneous-RGibbs and a Dynamic-Mixer (before or after the RGibbs), instead of PFR-RGibbs. Basically PFR-RGibbs is not a distributed model therefore there won't be real Plug-Flow effect at all.
2) The drawback in integration performance may be from the complexity in delay function and volume calculation. It is not directly related to RGibbs calculation. In Aspen Plus Dynamics, RGibbs is (only one!!) the procedural model, which reuses A+ RGibbs calculation. It means its computational performance in dynamics (for RGibbs block) is identical to what A+ exhibits. Basically it carries out series of SS calculation continuously along integration time.
Keywords: RGibbs, PFR, Delay function
References: None |
Problem Statement: In a larger pressure driven simulation only a portion of the model is anticipated to have reverse flow possible. In order to minimize the number of variables and equations for the problem, is it possible to setup only a section of a flowsheet for reverse flow? | Solution: No, all models use the GlobalRFlow parameter. There is no local parameter that overrides the global setting.
Keywords: Pressure driven
Reverse flow
References: None |
Problem Statement: Why do my PID Loops continuously report being Not Licensed?
Symptom: Aspen Watch Maker (Tools | Tag Maintenance | PID) shows Not licensed for all PID loops.
Cause: The TSK_PID1 task in InfoPlus.21 is the task responsible for checking out the PID collect licenses for the PID loops added in Aspen Watch Maker. If the correct PID licenses for Token: SLM_APC_PID (and the required number of them) are available in the SLM profiler, then the problem may be related to the InfoPlus.21 Task Service logon user account. The Log On As setting for the Aspen InfoPlus.21 Task Service controls what user identity the TSK_PID1 external task uses to perform licensing activities. If the software was installed as a local administrator account and then the system was registered on the domain and the Log On As account changed to use a domain account, then this could prevent TSK_PID1 the necessary permissions for being able to checkout licenses. | Solution: Open the Services window on the Aspen Watch server and try changing the Log On As setting for the InfoPlus.21 Task Service to be a local administrator account (account used to install the software). Then Restart the Task Service and restart InfoPlus.21 database using InfoPlus.21 Manager.
Keywords: Aspen Watch
PID Loops
License
References: None |
Problem Statement: What is the Aspen Cim-IO Interface Manager? | Solution: The Aspen Cim-IO Interface Manager provides an improved method of configuring Aspen Cim-IO Interfaces.
Here are a few tips for using the Aspen Cim-IO Interface Manager of creating an interface.
· Interface names of 10 characters or less are recommended.
· Aspen Cim-IO environment variables are found at the top Cim-IO Interfaces tree. Customers should review the variables and descriptions found in the Aspen Cim-IO Users Guide and make appropriate setting for the system.
· Each interface may have additional configuration arguments found at the interface type or interface level. Customers should review the arguments and descriptions found in the interface specific users guides and make appropriate setting for each interface.
· Aspen InfoPlus.21 systems include a companion utility Aspen Cim-IO IP21 Connection Manager used for configuring a connection to an interface.
Keywords: Connection Manager
References: None |
Problem Statement: The CIMIO_MSG.LOG is showing errors such as,
Could not create server xxx on node yyy on try number zzz, error is = Access is denied
 and the get records may display a Communication Failure in IO_DATA_STATUS_DESC | Solution: If you are connecting to your OPC server using a tunneler, make sure the correct server is selected in the Aspen InfoPlus.21 Administrator CIM-IO wizard tool.
In the OPC server select dialog, make sure you choose the tunneler server and NOT the actual node name of the OPC server.
Keywords: tunneler
OPC
communication failure
access is denied
References: None |
Problem Statement: Can the security and BPE profile specifications that are stored in the AFWDB Aspen Framework Database be transferred to other AFWDB Database Servers? This can help improve the rollout of configured Aspen Framework | Solution: s.
Solution
Yes. The AFWTools utility located in the Business Process Explorer installation directory can be used for this purpose. The AFWTools utility Export button on the Transfer AFWDB Data tab can be used to export AFWDB Profile, Role and Applications specifications to xml files. The xml files can be imported to AFWDB databases on other servers using the Import button on this same form.
Keywords: AFWDB
References: None |
Problem Statement: How can I plot the distillation curve showing the ASTM D86 temperature of a stream in Aspen Dynamics? | Solution: You can use flowsheet constraints for this purpose.
CONSTRAINTS
// Flowsheet variables and equations...
// Petroleum Properties - Propset Properties Interface - Class II procedures
VolPctSet as integerset ([1:9]);
VolPct(VolPctSet) as percent (fixed);
VolPct(1) : 0;
VolPct(2) : 5;
VolPct(3) : 10;
VolPct(4) : 30;
VolPct(5) : 50;
VolPct(6) : 70;
VolPct(7) : 90;
VolPct(8) : 95;
VolPct(9) : 100;
D86T(VolPctSet) as temperature;
for i in VolPctSet do
CALL (D86T(i)) = pPropZPct ( D86T, streams(C101F-1).Zn, VolPct(i));
endfor
END
This will calculate the ASTM D86 temperature for the stream C101F-1 for the specified volume percentages. You can then create a profile plot to display those values.
Keywords:
References: None |
Problem Statement: There are a number of problems when manipulating PID loops in Aspen Watch Maker. The problems include:
- problems when deleting PID records
- problems when going from fast scan to normal scan.
- unable to change IO device
- unable to change scan frequencies
- when scan frequency is changed, the change is not reflected in AW Maker?s Tag Maintenance screen.
- AW Maker shows incorrect Normal scan rate on re-import of existing PID loops | Solution: Download the attached zip file.
Create a subdirectory under ...\AspenWatch\ called patches
e.g. c:\Program Files\Aspentech\AspenWatch\patches
and unzip the contents of this zip file into that directory.
Run the batch file.
The batch file will save a snapshot of the current state of your database, and will then replace the procedures to fix the behaviors described above.
If there are problems, you can revert to this saved snapshot to restore original behavior.
Keywords: PID watch
References: None |
Problem Statement: Two issues are addressed with this patch:
Sometimes when the analysis doesn't complete in Aspen PID Watch, it is because of problems with Regional Settings. originally addressed in | Solution: 119711.
Also addressed in this new executable:
CQ00222647 Provide ability for user-defined scaling of limits on Raw Data plotSolution
The attached executable has been applied to Italian systems and resolved this problem. Stop / close any instances of the Aspen PID Watch application. This may work with other european settings, but be sure to save/ rename the original Aspen PID Watch executable before replacing it with this one, in case it doesn't. You will find the Aspen PID Watch.exe file in C:\Program Files\AspenTech\Aspen Watch.
The attached executable also has a new View menu option for Set Raw Data Plot Scale is added to allow user-specified plot scale limits for the process measurement and process output on the Aspen PID Watch Input Data Plot
Keywords: None
References: None |
Problem Statement: When I run the attached simulation in Aspen Dynamics 2006, I see the sum of the mole fractions in the liquid outlet stream show strange values. This happens after the liquid feed is stopped (valve B5 is closed) and the tank gets only a gas feed (N2 in stream 1). In fact, the sum of the mole fractions in the liquid outlet does not even add up to 1. What is happening? | Solution: Look at the level controller: you can see the level is dropping to zero at about 3.5 hr which is about the time you see the mole fraction sum to drop significantly from 1.
We are trying to take a liquid phase out of the flash drum, when there is actually no liquid phase present anymore. The liquid/vapor equilibrium is calculated from these equations:
y = K x (1)
sigma x = 1 (2)
sigma y = 1 (3)
(x molefractions in liquid, y molefractions in vapor, K equilibrium constants (function of T, p, from thermodynamic model). When you are in conditions where a liquid and a vapor phase can exist, you see some K values larger than 1 (volatile) and some smaller than 1 (heavies). Now, let's say we are above the dew point of the mixture (i.e. no liquid). In this case, all K values are greater than 1, say 2 for the discussion. Since we have sigma y = 1, we have also sigma (K x) = 1, which means 2 sigma x = 1, which means sigma x = 0.5, in other words, the mole fractions don't add up to one for the liquid phase. Obviously the equation (2) is no longer satisfied - it can only be satisfied when there is a liquid phase., This is done in Aspen Dynamics properties submodel props_flash2 - it's a private (AspenTech proprietary) model you cannot see its code. This explains why the sum of the mole fractions does not add up to 1.
The results in those streams are meaningless, not because the flowrate is zero, but because the origin of the stream (the liquid phase in the drum) has ceased to exist. In a more realistic model, we should see the vapor contained in the drum go to the liquid outlet (bottom), but that's not available in AD today. In the simulation, the streams have no volume, so when the flow stops in a stream, the results may be a bit disconnected from reality, making the interpretation a bit more tricky. But once you understand what is happening, we think the fact those results are meaningless should be less of a concern.
Keywords: None
References: None |
Problem Statement: How can I monitor a remote CIM-IO server for important performance aspects such as CPU utilization, disk space, etc? Can I use the Health Monitor? | Solution: While it would be necessary to install Health Monitor in the remote server, this is not always a possibility or a preferredSolution. The attached SQL+ script makes use of the TYPEPERF command to probe a remote machine - in this example CIMIOSERVER - for its current CPU usage and save this information to an analog tag named CpuRemoteUsage.
Save the query as a CompQueryDef and schedule its periodic execution in IP.21 administrator. You can then use set up alarms for CpuRemoteUsage values that shows a high cpu activity according to your needs.
Make sure the account running the InfoPlus.21 Task Service belongs to the remote server's Performance Log Users group.
You can use TYPEPERF to get many different types of performance counters both locally and from a remote server. Check its command line help using TYPEPERF -? or the Microsoft website for more examples:
http://technet.microsoft.com/en-us/library/cc753182.aspx
Keywords: TYPEPERF
Performance Counters
References: None |
Problem Statement: Does the securable component enterpriseobjects.xml still exist? | Solution: Enterprise Objects hasn't been delivered since Aspen Framework 2.6. Enterprise Objects is no longer in active development.
Keywords: local
security
References: None |
Problem Statement: When attempting to start the Aspen CIM-IO Manager Windows service the process fails and an error dialog box appears:
Windows could not start the Aspen Cim-IO Manager service on Local Computer.
Error 1053: The service did not respond to the start or control request in a timely fashion.
There are few other symptoms or useful evidence of the cause of this problem. The CIMIO_MSG.LOG file has no new messages at all. In the Windows Event Viewer there are at least these two Error events:
1. The Aspen CIM-IO Manager service failed to start due to the following error: The service did not respond to the start or control request in a timely fashion.
2. A timeout was reached (30000 milliseconds) while waiting for the Aspen CIM-IO Manager service to connect. | Solution: 1. One of the first things that the CIM-IO Manager Service does is to parse the Windows services file, looking for the port entry for the service labelled CIMIOManager. Test whether this file is causing the problem:
First back-up the existing services file:
C:\Windows\System32\drivers\etc\services
Then modify the contents of the services file so that it only has one line, the CIMIOManager entry (so remove all comments as well). This leaves one line, typically:
CIMIOManager 7777/tcp
Save the modified services file – you will require administrator rights to complete this. Then attempt to start the Aspen CIM-IO Manager Windows Service. If the service starts without error then it is clear that the parsing of the services file is failing with the original file. Restore your backed up services file and remove any non-standard entries, in particular long comment separator lines and anything that looks like an extremely long port number. Making such changes should resolve the problem.
2. Make sure that the PATH system environment variable includes the following folder:
C:\Program Files (x86)\Common Files\AspenTech Shared\
If this was missing then the CIM-IO Manager cannot start. Please correct the PATH variable.
3. Check that all the Cim-IO files have the same version number. You can find a list of such files in the release notes of any full Aspen Cim-IO server patch. If you have recently applied a patch then reapply the patch having read all the installation instructions carefully - in particular unblock the zip file before extraction and also extract the files EVERY TIME you attempt to install the patch.
4. Ensure all anti-virus software has AspenTech folders in their exclusion list.
5. If the above does not fix this problem and you continue to get 1053 error and no messages in CIMIO_MSG.LOG then you should repair the installation.
Keywords: crash
Exception code: 0xc0000409
CimioManager.exe
References: None |
Problem Statement: When seeing error 55 no buffer space available in the cimio_msg.log file or if experiencing a drop of data on VMS with UCX machines, set the number of large buffers to a bigger value. | Solution: If you do a show communication command from the UCX prompt, part of what you get back looks like this (the values will be different)
Type: Ethernet
Free
Maximum
Max Bytes
Minimum Min
Bytes
Large buffers
20
200
377600
10
18880
Small buffers
150
1000
256000
50
12800
In order to fix the problem you may have to adjust these parameters. The commands used to make these adjustments include::
set communication /large=max=1000
set communication /small=max=3000
If you go to the UCX prompt (by typing 'UCX' at the DCL prompt) you can do a
help show communication
You could use the following commands:
$ ucx show comm
$ ucx show comm/memory
$ ucx set comm/large_buffer=max:1000
$ ucx set config comm/large_buffer=max:1000
$ ucx show comm
$ ucx show comm/memory
Set it to even bigger than 1000 if necessary. The default is 200 and is too small in many cases.
Also, the help file recommends you set the number of small buffers to approximately 3x the number of large buffers. To do this simply execute the commands outlined, then execute them again substituting the word small for large in the commands.
It's also nice if possible to set the minimum values for each of these to about 1/2 to 3/4 of the max.
$ ucx set comm/large=min=750
WARNING: In order to do this you have to stop UCX first, meaning network connection will be lost.
eco 4 for UCX 4.2 will partially solve this issue.
Keywords: errno=55
buffer space
References: None |
Problem Statement: When installing the CIM-IO core on a Sun Unix system, running cimio_install returns an error cimio_install : not found | Solution: The problem is caused by extraneous control characters (carriage control, line feed) at the end of each line. Remove them and the procedure will run correctly. This problem has been reported to development and will be fixed in a future release.
Keywords: sun
unix
installation
line-feed
carriage-return
References: None |
Problem Statement: When the network connection between the CIM-IO Server and CIM-IO Client nodes is broken, a problem can occur where the CIM-IO connection doesn't re-establish itself for a long period of time - even after the network connection has been restored.
Several tests have shown that when Store&Forward is NOT being used, if the network connection between CIM-IO Server and Client is broken for several minutes, the CIM-IO connection can take over an hour to re-establish and begin collecting data again.
When this problem occurs, there will be numerous messages in the CIMIO_MSG.LOG file on the CIM-IO Server node of the form:
CIMIO_OPC_RECEIVE_FAILED Error Receiving from TSK_M_XXX on Node IP21_SERVER CIMIO_MSG_RECV_NOPIPE, Connection was somehow broken ( Broken PIPE ) CIMIO_SOCK_RD_BROKEN_PIPE, Connection was terminated by peer System Error, errno=38 Filename too long
Where TSK_M_XXX represents the name of the main CIMIO client task used on the CIM-IO Client and IP21_SERVER is the node name of the CIM-IO Client node. | Solution: To resolve this behavior, install Engineering Release CI010712A.NTI. This ER can be downloaded from the support website as Knowledge Base Document ID 105717.
Keywords: errno=38
References: None |
Problem Statement: Before v9.0, it was impossible to use Aspen Cim-IO Interface Manager to set <TIMEOUT> <DEVICE> <MSGS>< NOTAGINFO> arguments on the Cim-IO Store & Forward (S&F) processes. This | Solution: describes how to use the enhanced v9.0 Cim-IO Interface Manager to set additional parameters for the S&F processes.Solution
Starting with v9.0, you can use Aspen Cim-IO Interface Manager to set startup arguments on the Cim-IO Store & Forward processes. Refer to Chapter 11 of the Cim-IO User Guide or Knowledge BaseSolution #105498 for more information regarding these startup arguments.
In order to change process configuration you first need to stop the Store & Forward enabled Interface. Changes can now be made.
Select the service you wish to configure from the list at the top of the window: choose either the Cimio_sf_scanner.exe, Cimio_sf_store.exe or Cimio_sf_forward.exe.
You should then click the action labeled “Change\View process configuration” on the right edge of the window:
A dialog window will appear with the appropriate additional parameters for each of the S&F server process.
1. The Scanner process dialog has edit boxes for the Send Timeout, No Tag Info and DEVICE parameters:
2. The dialog window for the Forward process has edit boxes for the Send Timeout and MSGS parameters:
3. The dialog window for the Store process only has an edit box for the Send Timeout.
Make the changes you require. On clicking the OK button on the dialog window, the changes are saved to the Interface’s CSD (text) file in the CIM-IO management folder.
You can then restart the interface.
Check the CIMIO_MSG.LOG file on the Cim-IO server to confirm that the configuration overrides are applied as you expected.
Keywords: CQ00559525
Command Line
Cimio
timeout
Cim-Io
References: None |
Problem Statement: Problem in PID Watch configuration for Yokogawa Centum XL DCS
There is a need to modify the existing Yokogawa Centum CS configuration files to pick up the proper MODE from EXAOPC. | Solution: For the simplest interim Centum XLSolution, the following is recommended:
1. Make a backup copy of the AW_PIDC_CUSTOM2.cfg file in the %ASPENWATCH%\etc\sql\Pid folder (for example: rename as AW_PIDC_CUSTOM2.cfg.bck and AWP_PIDC_CUSTOM.sql.bck to save the original files)
2. Copy the existing AW_PIDC_CENTUM.cfg file to AW_PIDC_CUSTOM2.cfg.
3. Edit the AW_PIDC_CUSTOM2.cfg file using a text editor, and copy the current line that specifies the AW_A1 to .MODE mapping
4. Comment out the line that uses the .MODE attribute (using a # sign in position 1)
5. Modify the copied/second line, replacing .MODE with .LS, as shown below (refer to attached file)
Note that the text columns in this file are tab-delimited
[MEDIUM]
#AW_A1 ASCII ~.MODE Control block mode: Centum CS3000
AW_A1 ASCII ~.LS Control block mode: Centum XL
6. Also note that the Centum XL DCS mode for Remote/Auto is 'SPC', rather than 'RCAS' as used in the Yokogawa Centum CS DCS. Copy the attached AWP_PIDC_CUSTOM2.SQL into the %ASPENWATCH%\etc\sql\Pid folder.
7. Export the existing Centum XL PID loop definition records (only), if necessary, to create the tag information input file(s)
8. Re-import the existing loaded Centum XL PID Loops (only) using the CENTUM DCS Type
This operation will reconfigure the IO connections without deleting the existing PID Loops or losing history information
It is recommended to import a single loop initially to make sure this operation works successfully.
Note:
The updated AW_PIDC_CUSTOM2.cfg and AWP_PIDC_CUSTOM2.sql files
need to reside in the %ASPENWATCH%\etc\sql\Pid folder and the
modified AWP_PIDC_CUSTOM2.sql file needs to be re-saved to overwrite the
existing ProcedureDef record.
To do this --
1. Open the AWP_PIDC_CUSTOM2.sql file in SQLplus
2. Select the Record | Save As menu option
3. In the Save Record dialog, set the record name = AWP_PIDC_CUSTOM2, by removing the .sql extension
4. Select the Definition = ProcedureDef
5. Click the OK button to overwrite the existing ProcedureDef record
Once the loops are imported/configured using the modified AW_PIDC_CUSTOM2.cfg file - then the IoGetDef records are used to access data from the configured entries
Note that it is planned to produce a version 2006.5 CP2, which should include this additional CENTUM XL DCS configuration option, and also would include these same changes in (future) V7.1 patch and the current V7.2 release.
Keywords:
References: None |
Problem Statement: USERACM reactions are created in Aspen Custom Modeler using the Aspen Reaction Toolkit framework. The reaction kinetics is implemented in a few models, which can be created using the Reaction Wizard. Once the code is completed, the model can be exported in a similar way to the Model Export feature, to allow the model to be used in Aspen Plus. USERACM reactions are an alternative to fortran user subroutines for custom kinetics.
The USERACM reaction types can be used in RCSTR and RPLUG blocks.
Can you use USERACM reactions with Aspen Dynamics? That means, once I've created my simulation in Aspen Plus using those USERACM reaction types, can I then export the simulation to Aspen Dynamics and use it for dynamic simulation? | Solution: Yes, this is possible. See the attached examples which illustrate the steps required for RCSTR and for RPLUG models.
We assume the reader is familiar with Aspen Custom Modeler (including the Aspen Reaction Toolkit and Model Export features), Aspen Plus and Aspen Dynamics. The note is written for version 2006.
Step 1
We need to create a custom reaction type in Aspen Custom Modeler. This is explained in another note and will not be repeated here. The custom reaction type is a modified LHHW kinetics which account for coking of the catalyst. The custom reaction type is in the file Rel12Coking.acmf. The custom reaction type was created in version 12.1.
open the file Rel12Coking.acmf in ACM
do a right mouse click on the model CokingRxnModel, select Export
select Model Installation Package option to export the model as msi file
install the model
This step requires the Microsoft Visual C++ 2003 compiler.
Step 2
Now we need to use the reaction type in Aspen Plus. The file useracm.bkp contains a flowsheet with a RCSTR block. The file useracm-rplug.bkp contains a flowsheet with a RPLUG block.
RCSTR example
open the file useracm.bkp in Aspen Plus
run the simulation
export the simulation as flow driven to Aspen Dynamics
When you export the file, you get a warning explaining the steps required in Aspen Dynamics to actually use the custom reaction type.
open the file useracm.dynf in Aspen Dynamics
do an initialization run
activate the custom model option (under Tools, or under Tools, Settings)
copy the RCSTR3 model from the Dynamics library (Reactors) to Custom Modeling, Models
accept to update the blocks with the new model
edit the model RCSTR3 and apply the following changes
Change IRxnCfg([1:nRxnCfg]) as external ARTRxnCfg to IRxnCfg([1:nRxnCfg]) as external CokingRxnCfg (line 1528)
Change IRxnCfgModel([1:nRxnCfg]) as ARTRxnCfgModel to IRxnCfgModel([1:nRxnCfg]) as CokingRxnCfgModel (line 1529)
Change IRxnModel([1:nRxnCfg]) as ARTRxnModel to IRxnModel([1:nRxnCfg]) as CokingRxnModel (line 1530)
Change the equation QReactART = SIGMA(ForEach(i in [1:NRxnCfg])IRxnModel(i).QRxnCorr)*V to QReactART = 0 (line 1676)
Compile the custom model
Open the reactor AllVariables table and change NRxnCfg to 1
Change IRxnCfg(1) and select the name of the custom reaction model that was exported from Aspen Plus (R_1).
The file after those changes has been saved as useracm-modif.dynf, which is ready to be used for dynamic simulation.
RPLUG example
open the file useracm-rplug.bkp in Aspen Plus
run the simulation
export the simulation as flow driven to Aspen Dynamics
When you export the file, due to a defect, you do not get a warning explaining the steps required in Aspen Dynamics to actually use the custom reaction type.
open the file useracm-rplug.dynf in Aspen Dynamics
do an initialization run
activate the custom model option (under Tools, or under Tools, Settings)
copy the RPlugPDE model from the Dynamics library (Reactors) to Custom Modeling, Models
accept to update the blocks with the new model
edit the model RPlugPDE and apply the following changes:
Change IRxnCfg([1:nRxnCfg]) as external ARTRxnCfg to IRxnCfg([1:nRxnCfg]) as external CokingRxnCfg (line 939)
Change IRxnCfgModel([1:nRxnCfg]) as ARTRxnCfgModel to IRxnCfgModel([1:nRxnCfg]) as CokingRxnCfgModel (line 943)
Change IRxnModel([1:NRxnCfg],[1:XLen.EndNode]) as ARTRxnModel to IRxnModel([1:NRxnCfg],[1:XLen.EndNode]) as CokingRxnModel (line 953)
Change the equation Q_rxn(i) = SIGMA(ForEach(ICfg in [1:NRxnCfg])IRxnModel(ICfg,i).QRxnCorr) to Q_rxn(i) = 0 (line 1028)
Compile the custom model
Open the reactor AllVariables table and change NRxnCfg to 1
Change IRxnCfg(1) and select the name of the custom reaction model that was exported from Aspen Plus (R_1).
Please note the line numbers may change if cumulative patches or new versions modify the reactor models.
The file after those changes has been saved as useracm-rplug-modif.dynf, which is ready to be used for dynamic simulation.
Keywords: None
References: None |
Problem Statement: What value should I enter for the internal diameter of the bed if an internal heat exchanger is present in the bed? Do I need to add a correction? | Solution: You should enter the actual diameter of the adsorbent layer. There are two ways that the program uses the diameter of the bed: to calculate the external area of the bed for heat transfer to the environment, and to calculate the cross-sectional area of the bed to determine the relationship between flow rate and velocity. In the former case, the actual diameter of the bed should always be used. In the latter case, you have the calculations in place to remove the specified heat exchanger cross-sectional area from the cross-sectional area calculated from the specified bed diameter.
Thus, in both cases, the calculations will be correct if the actual diameter of the adsorbent layer is used (i.e., you should not make any corrections for the heat exchanger area).
Keywords: Adsorber, radius
References: None |
Problem Statement: What are the manipulated variables for controllers automatically added by Aspen Plus during the process of exporting to dynamics? | Solution: This is usually block specific, and dependent on whether it is flow-driven or pressure-driven.
However the rules of thumb is that if the model is flow-driven, then the manipulated variables would be various flow rates; if the model is pressure-driven then the manipulated variables would be valve positions whenever applicable.
To find out details for each block, do a search in the online manual of Aspen Plus Dynamics using literal phase
Pressure and Level Control for
and you would find a number of topics found. Select one of them, say Pressure and Level Control for RadFrac, you would read:
Keywords: controllers, flow-driven, pressure-driven, default controller
References: None |
Problem Statement: What do you mean by the quality in pressure safety valve model results? | Solution: In all relief valve models available in Aspen Plus Dynamics, QUALITY is defined as:
(1) PSV, PSV2, BURSTINGDISC, ORIFICE, and TVALVE
Quality_in = vf * mw (vapor) / Mw
Quality_out = vfo * mw(Vapor Outlet) / Mw
MW - Overall Molecular Weight
vf: Vapor Fraction
(2) DELTAP
Quality_in = vf_in * mw (Vapor in) / Mw
Quality_out = vf * mw (Vapor Out) / Mw
(3) EXPANSION
Quality_in = vf * mwv (Vapor in) / Mw
Quality_out = vf_o * mwv_o (Vapor Out) / Mw
Note: Mathematically, quality is defined by the relationship: x = mass of [[vapor]] / total mass.
One may be able to calculate mass flow rate of vapor and liquid from the term quality.
Keywords: Quality, vapor fraction, MW
References: None |
Problem Statement: Rgibbs Does Not Support CSTR Option | Solution: In earlier releases Rgibbs supported the CSTR option. As with Rstoic and Ryield this option was modeled by mixing the feed streams into a dynamic vessel, the mixed output of the vessel was then fed into an instantaneous adiabatic reactor. The CSTR option has been withdrawn from Rgibbs at 2006.
If you wish to model an Rgibbs reactor dynamically you should add a mixer to the product stream(s) and specify the mixer vessel geometry on its dynamic form.
Keywords: RGibbs, CSTR, option
References: None |
Problem Statement: Why does the multiply block in the control signals library show significantly greater values on the output when the input is used to calculate the output according to the following formula:
Input1*Input2=Output. | Solution: When using the multiply block it is not really a straightforward controller as it may appear. From the outset it looks as if the calculation is Input1*Input2=Output. But its not that simplistic, this model uses scale factors to adjust the units of the variable to work within metric units in the background that get used by this block(the scale factors are declared in the variable type of the variable used).
In fact the real calculation that the multiply block uses is
Input1/Scale1*Input2/Scale2=Output/Out_Scale.
Keywords: Multiply, Control signal, input, output, scale factor
References: None |
Problem Statement: When using an ACM model exported from Aspen Plus do you need an ACM license in order to run the model? | Solution: An ACM license is not required to run an ACM model that has been exported from Aspen Plus. However, if you want to modify the model then you will have to enable Custom Modeling from the Tools menu. Then, the ACM model will appear in the Custom Modeling folder where it can be modified. Modifying the model will require an ACM license.
Keywords: ACM model export, ACM license
References: None |
Problem Statement: When exporting an Aspen Plus simulation to Aspen Dynamics, there is a choice of a Flow Driven simulation and a Pressure Driven simulation. Which one should I choose? | Solution: In an Aspen Plus steady-state simulation, the outlet stream pressures and flow rates of a block are determined from the inlet conditions to the block, and the specifications for the block. Neither the outlet stream pressures or flow rates are affected by the pressure in the downstream blocks. This approach is called Flow Driven simulation.
Flow driven dynamic simulations work in the same way as in Aspen Plus simulations. For each model, fixed rules are used to determine outlet flow rates and pressures, given the inlet conditions to the block. In some cases, the outlet stream flow rates are determined/manipulated by pressure or level controllers which are automatically added when the dynamic simulation is created. The rules used for each model are given in the Aspen Dynamics
Keywords: Flow driven
Pressure driven
Pressure Checker
Simulation mode
References: chapter of the Online Help.
The flow driven approach is well suited to a wide range of dynamic simulation applications. In effect, this approach makes the assumption of perfect flow control. This is often a good assumption, particularly when modeling liquid only systems. For liquids, the pressure/flow dynamics are very fast, and the assumption of perfect flow control is usually accurate.
In some simulations, it is necessary to take into account the effect of downstream pressures on flow rates in streams. For example, consider two tanks containing vapor that are connected by a valve. The pressure in the two tanks determines the flow rate through the valve. If the pressure rises in the downstream tank then the flow between the tanks will decrease, as the pressure driving force is reduced.
To account for the effect of downstream pressure, it is necessary to create a Pressure Driven simulation. In pressure driven simulations:
The pressures of all feeds and products to the flowsheet are fixed
Feed flow rates are not fixed
All flow rates in the flowsheet are determined by the pressures and pressure/flow relationships around the flowsheet
The correct simulation mode to use depends on your modeling objectives. In general, if pressure is important to you, then Pressure Driven may be required. The correct simulation mode also depends on the type of process. Typically, simulations consisting of mostly gas or vapor phase streams will require Pressure Driven mode. Some examples of these systems are steam networks, gas networks, pressure relief systems and compressor networks. Conversely, simulations that consist of mostly liquid streams will not require Pressure Driven mode.
The control system for your simulation should also be considered. If you know you already have a good pressure and good flow control, then Flow Driven simulation may be suitable. Also, the effect of pressure on physical properties should be considered. Pressure can have a large effect on gas stream properties, such as densities, or on reaction kinetics in some cases.
A Pressure Driven simulation usually requires more blocks to be used to properly model the pressure/flow relationship throughout the model. The Pressure Checker from the Dynamic toolbar in Aspen Plus can be used to analyze the flowsheet for a suitable configuration for Pressure Driven simulations. See the Online Help in Aspen Dynamics for more information on how to use the Pressure Checker tool. |
Problem Statement: How do I reduce the size of a *.dpp file? | Solution: When a user does a 'save-as' on a large *.dpp file, it should get smaller. In fact, it is a best practices to do a 'save-as' periodically. When DMCpus Model needs more space, it grabs more space, but as existing memory is freed up, Model cannot always take advantage of that freed up space. Doing a 'save-as' will compact all of the objects together and make for more efficient use of the space.
Keywords: DMCplus Model, dpp
References: None |
Problem Statement: How can I activate the PID Group Configuration on the Aspen APC Web interface ? | Solution: In order to activate the PID Group Configuration on the Aspen APC Web interface, it is possible har dcode the variable in the AWPIDGroupConfig.asp file to true.
Comment out the following line and hard code the value to true.
var userCanRun = (1 == Session(NewWebProvider) ? Session(WebMgr).CanManage : Session(WebMgr).HostMgr.CanManage);
changes to:
//var userCanRun = (1 == Session(NewWebProvider) ? Session(WebMgr).CanManage : Session(WebMgr).HostMgr.CanManage);
var userCanRun = true;
Keywords:
References: None |
Problem Statement: Run-time error ' 521' Can't open Clipboard. Uncertainty graphs either don't open or the program is closed immediately. | Solution: Close any Microsoft desktop tools that may be using Clipboard, retry Aspen Desktop application.
Keywords:
References: None |
Problem Statement: How can I permanently disable the Aspen Simulation Workbook (ASW) (Design and Run) toolbars so that they will not re-load when I start Microsoft Excel? | Solution: To permanently disable the Aspen Simulation Workbook toolbars please follow the procedure below:
1. Open the Microsoft Excel
2. From the main menu bar, click on Tools | COM Add-Ins...
3. De-activate the checkbox beside the Aspen Simulation Workbook 200X.X and click OK
If you don't see the COM Add-Ins... option described above, please follow the procedure below to add the COM Add-Ins... to the list:
1. Click Tools | Customize from the main menu bar
2. Click the Commands tab
3. Under Categories, click Tools
4. In the Commands list, select COM Add-Ins...
5. Click the Tools menu and drag the COM Add-Ins item to this menu (just below the Add-Ins command) before closing the Customize dialog box
6. Run the COM Add-Ins... command you just added to the Tools menu to disable ASW
Please note that any time you want to load ASW you need to follow the procedure below:
1. Open the Microsoft Excel
2. Under the top menu bar go to Tools | COM Add-Ins...
3. Activate the checkbox beside Aspen Simulation Workbook 200X.X and click OK
Keywords: disable, ASW, Excel, toolbar, COM Add-Ins
References: None |
Problem Statement: How to Access to DEP prediction or estimate for intermittent variables? | Solution: The current prediction is not available in the parameter list for intermittent variables but you can calculate it by taking the DEP and adding the PREDER to it.
Since PREDER = Prediction ? Actual.
If you have a long time to steady state the PDEPC001 and PFMDEP001 is a good estimate of the current PRED without any additional calculation, because the difference between the current prediction and the one at time 001 is small.
To perform this calculation.
Right click and then Add a New Entry
Then we define an output calculation since we need to calculate after the control runs the prediction.
CPRED then can be then used in another calculation.
Keywords: DEP
Intermittent
DMCplus Build
References: None |
Problem Statement: Which offline Advanced Process Controll (APC) applications use the APC_Builder license key? | Solution: The Aspen APC offline tools used to check out different license keys when used along with the old licensing model (Perpetual). However, under new Token license agreements (starting July 2009), the offline license keys have been consolidated into a single license key called APC_Builder. Listed below are the applications that check out the APC_Builder license key at run time:
Aspen Process Controller Builder / APC Builder
Aspen DMCplus Model
Aspen DMCplus Simulate
Aspen IQconfig
Aspen IQmodel
Aspen Nonlinear Controller Model
Aspen SmartAudit
Aspen Process Statistical Analyzer
Aspen Watch Performance Monitor / Aspen Watch Maker
Aspen RTO Watch Maker
Aspen PID Watch Performance Monitor / PID Watch
Aspen Process Recipe Explorer
Keywords: APC_Builder
License
Offline APC Tools
References: None |
Problem Statement: How to disable the Open Simulation Environment (OSE) Workbook from Excel after it has been installed. | Solution: .
There are known performance issues when starting Excel when OSE workbook is installed. This is largely due to the .NET runtime being loaded into excel.
Option 1
To disable the Aspen OSE Workbook 2004.1, use the following procedure:
1. Select View | Toolbars and switch on the Visual Basic toolbar.
2. Select Tools | Customize | Commands tab | Tools category, and scroll down about 30 commands to find COM Add-Ins.... Click on COM Add-Ins and drag it onto the Excel menu toolbar. A good location to install this would be below Tools | Add-Ins.... option.
3. Close the Customize dialog box.
4. Select COM-Addins and uncheck either 'Aspen OSE Workbook 2004.1' or 'Data Framework Toolbar'.
Option 2
You can also disable Excel Addins by setting registry value to the following:
HKEY_CURRENT_USER\Software\Microsoft\Office\Excel\Addins\<Add-In Name>\@LoadBehavior to 2.
To enable set it to 3.
Notes:
At the moment the installer does not allow you to turn off the COM Addin for the OSE workbook. Development is investigating to add this feature as a default option in the future.
Keywords: Workbook
OSE workbook
COM
Open Simulation Environment
References: None |
Problem Statement: What might prevent the PID Tuning (or Model Identification) window from opening or from returning an error message? | Solution: One possible reason for the windows to not show up could be that the window was off the visible screen area due to disparity in screen reSolution. By default, the PID Watch dialogs are opened in the center of the display, but the Top and Left pixel positions are saved when the dialog is closed - so the window will show up the same position as previously moved by the user.
These various dialog positions (and other user-entered preferences) are saved in the Computer\HEKY_CURRENT_USER\Software\AspenTech\Aspen Watch Desktop\PID Watch registry folder.
Navigating to the above location in the system registry and changing the applicable parameters, which in case of PID Tuning window position would be Tuning Window Left and Tuning Window Top to a different number, say 10 for both would relocate the screen to the visible area.
Keywords: PID Watch
PID Tuning Window
Model Identification Window
References: None |
Problem Statement: I have an AspenWatch installation, which is working correctly with the only problem that it is not possible to define PID groups. Everything into the Group Configuration page in PCWS is greyed out. | Solution: It's greyed out because the user does not have Manage or Engineer Change permissions defined in the Security page for the web server host.
Visit the Configuration page of the web server, go to Security and expose the WebServer in the Host selection box. Then look at the Users and Roles and Permissions, and confirm the User has the appropriate Manage / Engineer Change permission assigned, when the WebServer host name is exposed.
Keywords:
References: None |
Problem Statement: What do different scan periods time scan in PID configuration in AspenWatch mean? | Solution: During the import of PID loop in AspenWatch, a fast scan rate, a normal scan rate and a medium scan rate are required.
The normal and fast scan rate work together to determine when those loops are scanned. Any loop can be put into either Normal or Fast scan using the tag maintenance in AspeWatch maker.
During the PID analysis run that are set up in PCWS, the PID loops for that group will also be put on FAST scan during scheduled interval. After the analysis is done, those PID loops will be put back to NORMAL scan.
The medium scan rate determines how fast the mode and windup parameters are read from the DCS. The recommended value is 60 sec.
Keywords:
References: None |
Problem Statement: How can a .clc formatted data file be imported into PIDWatch? | Solution: Currently there is no interface for selecting the appropriate PV, SP, OP inputs from the CLC file
Alternate method to retrieve data for PID Watch from a DMCplus CLC file:
DMCplus Model
1. Import CLC file into DMCplus Model
2. Select (highlight) the appropriate vectors in the List of All Vectors view
3. Right-mouse click and select the Export Vectors context menu option
4. Choose the Vector Files (*.vec) Export as file type option in the Select a Directory to Export dialog
PID Watch
1. Choose the File | Import Vectors menu option in PID Watch
2. Select the appropriate PV, SP and OP vectors in the Import Vector File Data dialog
3. Specify PID Loop Name, PID Loop Type, Time to Steady-State, PV and OP Limits, etc.
Note that a subset of the vector file data can optionally be imported specifying the Extract Range Start Sample and End Sample
1a. Alternately, create an AutoVecRun input file to import vectors for the multiple PID inputs (PV, SP, and OP vectors)
This is documented in the Aspen PID Watch Performance Monitor Help Exploring Aspen PID Watch | AutoVecRun help topic
2a. Choose the File | AutoVecRun menu option in PID Watch
3a. Multiple vector files are imported and the PID Analyses are automatically run following vector file import
Let me know if you have questions or need additional information
Keywords: clc, import, PIDWatch
References: None |
Problem Statement: How to check the number of tags that can be accessed in Aspen PID watch Performance monitor?
Or
Why can't I view all the PID tags configured in Aspen InfoPlus21, using Aspen PID watch Performance monitor? | Solution: It is possible that all the PID tags configured in Aspen InfoPlus21 could not be accessed through Aspen PID watch performance monitor. The reason could be that the maximum number of tags mentioned in Aspen Watch is not set correctly.
To modify the number of tags for PID watch, using Aspen Watch monitor,
1. Open Aspen Watch Maker
2. Go to Tools
3. Choose Configuration Options
4. Modify the field of Maximum ‘Tags’ to the required number
Keywords: PID watch
PID tags
Aspen Watch
References: None |
Problem Statement: PIDWatch only allows me to select out of the first 100 tags from the AW database, is this configurable? | Solution: Yes, the configuration of how many tags are visible from the Aspen Watch database is available under the Tools and then Options. There is input for Max Tags, 100 is default.
Keywords: Aspen Watch, PID Watch, tags
References: None |
Problem Statement: How do I prevent a validation error when adding a new CV a non existing sub controller appears in the ccf?
When adding a new variable to a CCF file it adds a sub controller that does not exist in the configuration file thus creating a validation error. If you try to delete this sub controller the action is not permitted since it is not listed in the sub controller area of the CCF. | Solution: This problem comes when there is a mismatch in the name of the sub controller defined in the template file and the ccf file. To avoid this problem perform either one of the following options:
1. Edit the template (*.TCC) in DMCplus Build so that it contain a valid sub controller that matches your CCF file. Or
2. Open the ccf file in notepad, locate the name of the variable and erase the sub controller entry. The parameter that binds a CV to a sub controller is CVINSB and for MV it is MVINSB. Note that it will appear in note pad as:
A .CVINSB~~~CONSTANT~~~CH(64)~~~SUB1&SUB2&SUB3~~~
a??SUB1a?? is the name of the sub controller. Just leave the sub controller name that you want the variable be part of and save the file.
Keywords: DMCplus Build, Template, Subcontroller
References: None |
Problem Statement: What causes SmartStep to make impulse like steps on MVs instead of the typical steps? | Solution: SmartStep if configured correctly, should results in steps in the MV setpoints. However, an incorrectly configured SmartStep controller can result in the behavior mentioned in the problem statement. Such behavior are typically seen if the SmartStep parameters for the controller are not configured correctly. For SmartStep to work properly, the engineer should ensure that the tuning parameters are specified properly. Some typical configuration for SmartStep tuning include-
1. Set Test Margin properly for the controller to have enough room to step the MVs. Test Margin for each CV needs to be more than 1% of the Operating Range.
2. Set the Operator Limits on the CVs such that SmartStep has enough room to step the MVs. At the same time, it is necessary to make sure that-
Low Operator Limit - Test Margin > Low Validity Limit
High Operator Limit + Test Margin < High Validity Limit
3. Set the SS Criterion on all MVs to MINMOV and set the SS Cost on the MVs to 1.0.
4. Specify the unique CV Limit Ranks based on the importance of the limits relative to other CV limits in the controller. Specifying unique CV Limit Ranks would allow the user to pay less (or no) importance to tuning the SS ECEs for the CVs, which can be tuned at a later time when more information is available on the process.
Keywords: SmartStep
Tuning
References: None |
Problem Statement: Running Aspen HYSYS Optimizer from Aspen Simulation Workbook | Solution: A function ASWHysysStartOptimizer() has been added in ASW V7.1. This can be linked to a command button in Excel spreadsheet. A screenshot of the Excel spreadsheet with the command button is given below.
The code linked with the command button is given below.
Private Sub CommandButton1_Click()
Call ASWHysysStartOptimizer
End Sub
The attached files contains a Aspen HYSYS simulation with a configured SQP optimizer and an Excel spreadsheet with ASW configured for the optimizer run.
Keywords: Aspen SImulation Workbook (ASW), Hyprotech SQP Optimizer
References: None |
Problem Statement: By default, Aspen Simulation Workbook (ASW) does not allow you to change an Aspen HYSYS Adjustable variable. | Solution: HYSYS variables whose modify state is Adjustable are calculated by HYSYS but also can be modified by users. An example of an Adjustable variable is a HYSYS worksheet variable. If you add an Adjustable variable to ASW, then by default it will be given an ASW variable status of Default and it will be set to read-only.
If you want to modify this value with ASW, then you have to set the read-only status of the variable in ASW to false. After that, you will be able to modify the variable in ASW and its value will be passed along to HYSYS.
The following table displays the mappings of HYSYS Variable Modify States to their corresponding ASW Variable Statuses:
Hysys Modify State
Modify State Description
ASW Variable Status
Calculated
non-modifiable calculated value
Calculated
Specified
user specified modifiable value
Specified
Adjustable
calculated but modifiable value
Default
Temporary
modified value being held or cached
Specified
Any other value
n/a
Missing
Keywords: None
References: None |
Problem Statement: Technical tips for configuring and troubleshooting PIDwatch through Production Control Web Server | Solution: The suggestions ofSolution 122691 “Technical tips for configuring and troubleshooting PIDwatch through Production Control Web Server” points still applies to the newer versions with some changes on the components, services and paths.
The six points mentioned on thatSolution should be followed
1. If upgrading the software installation, the first step is to apply the latest available Service Pack (Patch) and/or ER software updates on the appropriate system servers (Aspen APC Builder, Aspen APC Online, Aspen APC Performance Monitor and Aspen APC Web Server).
2. Second step, after installing the Aspen APC Performance Monitor software (Service Pack) is to run the Aspen Watch Install Database Configuration utility from the Start->Programs->AspenTech->Aspen Manufacturing Suite->APC Performance Monitor menu item. This will require a stop and restart of the InfoPlus.21 database when complete to update the Aspen Watch records.
3. Third step is to configure an ACOView shared folder on the Aspen APC Web Server host. You should setup this \inetpub\wwwroot\AspenTech\ACOView shared folder with Full Control permissions access only for the Aspen Watch database administrator (the Aspen InfoPlus.21 Task Service user), or alternately for a local Administrators group if the Aspen Watch administrator is a member of this local Administrators group.
4. Although not a required part of the PID Watch configuration - note also that the shared folders on the Aspen Watch/InfoPlus.21 database host should be configured for similar access permissions. The default software installation will configure the directories listed below for “Everyone” Full Control permissions. The “Everyone” share permission should be removed to reduce the chance of virus infiltration, and replaced with a local Administrators group with Full Control permissions which includes the InfoPlus.21 database administrator user. These shared folders include:
\%ProgramData%\AspenTech\InfoPlus.21\c21\h21\arcs
\%ProgramData%\AspenTech\InfoPlus.21\c21\h21\AggHis
\%ProgramData%\AspenTech\InfoPlus.21\c21\h21\EvtHis
\%ProgramData%\AspenTech\InfoPlus.21\db21\Group200
5. The ADSA Client Config Tool is used to configure the Aspen Watch server host appropriately as a Public Data Source. An ODBC System Data Source is then configured using SQLplus on localhost and selecting the appropriate Aspen Watch server as the Aspen Data Source.
Note: when running in the automated scheduling mode, the PID Watch program assumes (or uses) the “SQLplus on localhost” ODBC connection
6. A last important note is not to create PID Definition group record names containing spaces, or special non-alpha numeric characters - use underscores rather than spaces for record naming conventions.
In addition,
7. User the same account to start the Aspen APC Performance Monitor Data Service and Aspen InfoPlus.21 Task Service on the Performance Monitor (Watch) server and AFW Security Cliente Service and Aspen APC Web Provider Data Service (if using WCF) on the Web (PCWS) server.
8. Check the log files generated on \%ProgramData%\AspenTech\APC\<Vx.x>\Builder\PidResults. E.g. <PIDGroupName>.log, <PIDGroupName>_DbgAutoLoad.log and <PIDGroupName>_DbgAutoRun.log.
Find below an example of the contents:
Keywords: Group Configuration, Aborted, PIDWatch, PCWS
References: None |
Problem Statement: Getting an error when trying to connect Aspen Simulation Workbook (ASW) with HYSYS simulation case Failed to connect to Simulation. | Solution: This error in particularly comes up if you have multiple versions of HYSYS installed on your machine and the simulation is created using HYSYS 2006 or 2006.5 or higher version. The user will have two options to successfully connect the simulation to ASW.
1. From the windows Start menu go to Programs | AspenTech | Aspen Engineering Suite | Aspen HYSYS 2006.5 | Restore File Associations. Once you run the restore file associations, ASW will open the simulation with HYSYS 2006.5 and will be successfully activated. If the HYSYS simulation is created using v2006 or v7.0, run the Restore File Associations for that version.
2. Second option is to set the simulation to Exact Version under ASW. Whenever you are creating a ASW file in association with HYSYS, go to the ASW Organizer | Configuration | Simulations | Configuration and click Add to select the simulation and click Open. Now on the Configuration page set the version option to Exact Version from any version and type in the version number, for example 2006 or 2006.5 and for version 7.0 type as v7.0 and click OK.
the next time you open your ASW, HYSYS simulation will be connected using the version set under configuration.
Keywords: Connection, Failed, Failed to connect to Simulation
References: None |
Problem Statement: How can I import the flowsheet diagram from Aspen Plus or Aspen HYSYS into Aspen Simulation Workbook and be able to modify the units individually? | Solution: Aspen Simulation is a software that allows the user to link Aspen Plus or Aspen HYSYS to Excel in such a way that the process specifications and results are transferred instantaneously. However, there is not a direct way to import the process flowsheet diagram.
The general way to build the flowsheet in Excel is by manually inserting the unit operations if one go to the Aspen ASW tab | Design | Insert Icon. This allows the user to import customized unit operations as well since there are many different drawing extensions that can be selected: *.gif, *.jpg or *.pict, among others.
However, if the customer does not want to change any unit operation on the flowsheet, then the diagram can be imported directly with the following procedure:
- Select all the unit operations of the flowsheet.
- Go the Home ribbon and click on “Copy”.
- Open Excel and go to the Aspen ASW tab.
- The flowsheet is pasted as just one image. This can be quite annoying since it doesn’t allow to the user to insert any tables between the unit operations or close to them.
- Now, right click on the image and select Group | Ungroup.
- Now all the unit operations can be manipulated individually.
Keywords: Flowsheet, Copy, Diagram, Import Diagram, Unit Operations.
References: None |
Problem Statement: How can I change the liquid holdup in a packing when using the simple packing hydraulics option in RadFrac? | Solution: The liquid holdup is related to the liquid flowrate with the following equation (in Stage model):
rhol * Vl * stagearea = K_pack * LiqOut.F * V
where:
rhol: liquid molar density (kmol/m3)
Vl: stage liquid volume (m3)
stagearea: column cross section (m2)
K_pack: packing constant
LiqOut.F : liquid flowrate leaving the stage (kmol/hr)
V : total stage volume (m3)
The value of the fixed variable K_pack is set when exporting the simulation from Aspen Plus to Aspen Dynamics. The Hydraulics sheet in the Dynamics input form allows the user to specify the initial liquid volume fraction, which is the ratio of Vl/V at time 0. The default value is 5%.
Therefore, the easiest way to modify the liquid holdup is to set the correct value on the Dynamics form, Hydraulics sheet before exporting the simulation to Aspen Dynamics. However, it is not always convenient to go back to Aspen Plus. You can use a script combined with the initialization run mode to adjust the value of the K_pack variable.
The following script can be used:
' liquid volume fraction
volfr = 0.01
b = blocks(B1B)
disableincrementalupdate
for i=2 to b.nstage.value-1
' change initial conditions
b.stage(i).Vl.value = volfr * b.stage(i).V.value
b.stage(i).Vv.value = (1-volfr) * b.stage(i).V.value
Vlrhol = b.stage(i).Vl.value * b.stage(i).rhol.value
Vvrhov = b.stage(i).Vv.value * b.stage(i).rhov.value
for each c in b.componentlist.components
b.stage(i).Mc(c).value = Vlrhol * b.stage(i).x(c).value + _
Vvrhov * b.stage(i).y(c).value
next
b.stage(i).K_pack.spec = Free
b.stage(i).LiqOut.F.spec = Fixed
next
enableincrementalupdate
application.simulation.runmode = Initialization
application.simulation.run(true)
disableincrementalupdate
for i=2 to b.nstage.value-1
b.stage(i).K_pack.spec = Fixed
b.stage(i).LiqOut.F.spec = Free
next
enableincrementalupdate
To use it, create a script in the Flowsheet folder. You can specify the liquid volume fraction on the 2nd line (volfr is set to 1% in this example) and the name of the radfrac block (e.g. B1B) on the 3rd line. Make sure your simulation is restarted and that you have done one initialization run (if you have just exported the simulation from Aspen Plus but not yet run it in Aspen Dynamics).
Keywords: None
References: None |
Problem Statement: Default Performance Curve in Turbine (COMPR) | Solution: Aspen Plus Dynamics now supports a default performance curve for the turbine to give a more realistic dynamic simulation. If you did not enter performance and efficiency curves in Aspen Plus, then the curve Head vs. suction volumetric flow rate and Efficiency vs. suction volumetric flow rate for a turbine are used to give realistic behavior during a dynamic simulation. These typical curves are fitted around the operating point calculated in Aspen Plus.
The default performance curve allows the Aspen Plus Dynamics user to change the output of the turbine by varying the turbine shaft speed from the turbine configure form. The user has the option of not using the default performance curves by changing the value of the parameter UseCurves to False, in the Turbine Configure form.
Keywords: performance curve, turbine, compr
References: None |
Problem Statement: When an ACM model that has been exported to run in Aspen Plus is then exported to Aspen Plus Dynamics, where do you find the model in Aspen Plus Dynamics? | Solution: All of the Aspen Plus Dynamics models can be found in the Dynamics library in the Exploring - Simulation window. However, an ACM based models exported from Aspen Plus will be found in the Local Library folder
In this example, the model new_heater is an ACM model used in the Aspen Plus simulation that was exported to Aspen Plus Dynamics. All of the custom forms, scripts, icons, etc. associated with model when developed in ACM will be shown in the contents of the model folder. However, the model cannot be modified since the contents of the folder is read-only.
Keywords: ACM model export, ACM model
References: None |
Problem Statement: Token Licensing: how is Aspen PID Watch Performance Monitor licensed? | Solution: Token consumption of Aspen PID Watch Performance Monitor (formerly called Aspen PID Watch) is based on the number of PID Loops, i.e. the number of existing PID loop records. You can configure a PID loop to be collected and analyzed from within Aspen Watch Maker. The token consumption is written in your contract and is currently 1 token every 25 PID Loops. Tokens are consumed by ?Aspen PID Watch Performance Monitor? based on the number of PID loops created and not based on the number of PID loops that are in SCAN ON status.
Keywords: Token estimation
References: None |
Problem Statement: Built-in function @POW sometime causes Floating point error: INVALID Program will halt | Solution: The base value of @POW function has to be >=0. Addition of @abs function to the base value(or equation will prevent the Floating point error : INVALID Program will halt .
ex. @POW (@abs(base), exponent).
Keywords: Built-in function
@POW
References: None |
Problem Statement: In versions 2004.1 and older of Aspen Dynamics there was an Outlet_Relief port on FLASH2 blocks that allowed a Material Stream connection for a Pressure Relief Device. In version 2006, the port is labeled OBSOLETE - DO NOT USE. How do you connect a stream to a Flash2 block for a pressure relief evaluation? | Solution: For 2006, the FLASH2 vessel model was improved to provide many of the features that are included in the RCSTR model. As part of that upgrade, the ports configuration was changed and the Outlet_Relief port removed. The Out_V and Out_L ports now allow multiple connections where relief devices can be connected. The Out_Relief port is still included in the model allowing simulations which used the Out_Relief port to load correctly in 2006. However, the simulation will be underspecified until the user reconnects the relief streams from the Out_Relief port to the Out_V port.
Keywords: FLASH2, pressure relief, Out_Relief port, PSV
References: None |
Problem Statement: What is the procedure to modify a custom DCS type for PID in AspenWatch? | Solution: To edit the custom DCS type for PID loops in AspenWatch.A Follow the help file on AspenWatch maker, under the section set up PID loops and miscellaneous tags>Custom DCS types for PID monitoring.
A? Edit the AW_PIDC_CUSTOMX.CFG where X is 1,2, or 3.A The file is located in programdata\Aspentech\APC\Performance monitor\ect\sql\PID
A? Edit the AWP_PIDC_CUSTOMX.SQL where X is 1,2, or 3 by using SQLplus Query writer.
A? If you tried to open up the procedure and you get this error
It means that the procedure source code has never been edited. Thus you open the file AWP_PIDC_CUSTOMX.SQL in SQLplus writer by clicking on File > Open and navigate to programdata\Aspentech\APC\Performance monitor\ect\sql\PID and select the appropriate file.
After you edit the file, you can save the file but it won't get loaded into IP.21 until you choose Record>Save As and save over the existing procedure.
Once the SQL is saved, the next scan of the PID monitor will use the new code.A Remember it may change the structure of the DCS type and historical data before the change may not be available in PIDWatch desktop.
Keywords: None
References: None |
Problem Statement: How to improve the speed of Aspen Dynamics calculation? | Solution: Performance is often limited by the size of the largest group of simultaneous equations.
1. Simulations with recycles result in large groups of equations incorporating all blocks and streams within the recycle. Recycles needs to solve for temperature, pressure, flow and composition for each component.
2. Pressure-driven simulations usually result in very large groups of equations due to pressure/flow network equations, as theSolution of upstream blocks requires pressure information from downstream.
Since Aspen Dynamics V7.0, for flow driven simulations with recycle streams and for all pressure driven simulations, dynamic simulation performance can be improved by using stream tearing.
Stream tearing has been incorporated into the MaterialStream stream type and the Valve model.
Tearing in the MaterialStream is activated via a check box on the Configure form. This should ONLY be used for recycle streams in flow driven. See screen shot below:
For pressure-driven simulations, you must use a Valve model to tear the stream. The Valve model includes the pressure/flow derivatives to update the torn stream flow variable. The TearStream parameter on Valve's Configure form has 3 options:
1. No (default) Deactivate stream tearing
2. Full Tear recycle streams
3. PF-Only Tear the pressure-flow network in non-recycle streams
See screen shot below:
For further details on how to use this new feature, type in Stream Tearing in the online help's (F1) search tab.
Keywords: Stream Tearing, Performance, speed, slow, decomposition, solver
References: None |
Problem Statement: Can I mode transient pipe delay in Aspen Plus Dynamics ( APD)? | Solution: One should be able to model piping delay by choosingSolution method constant dPdL. However, the delay behavior in the Pipe using this option is limited and following are the pointer needed to keep in mind:
- Delay behaviors are designed only for Composition and Enthalpy (temperature)
- Flow rate is not to be delayed. And no compression effects are modeled therefore there won't be any delay in flow rate.
- When time constant (tau) is determined from cumulative volumes (Vcum and Vcum_old), Composition(z) and Enthalpy(h) could then be delayed accordingly
Keywords: Enthalpy, dP_dL, delay
References: None |
Problem Statement: How to increase the display time for plots of the dynamics simulation run?
Description: In Aspen Plus dynamics, If the simulation runs for long time, previous plot display data is continuously truncated. | Solution: If the result are continuously truncated for a given plot, previous simulation results can be loaded by following the steps below.
Select the object on the PFD (may be stream)
Right click to select the Form ll Select Plot (may be TPFm Plot)
In the Plot view, right click again and go to Properties
From Properties view click on Data tab || Load simulation Results for all time points now.
If the data is too crowded in the plot, Interval of the plot can be changed by adjusting the communication interval ( see above). You need to increase the communication hours to reduce the number of data in the plot results.
If above steps does NOT resolve the issue then you need to change the communication hours. To access it, go to Run menu and select Run options. Under Time control, increase the communication hours.
Note: Too small communication hours may lead to large set of values of a variable to be recorded over a period of time. It may cause problem while loading plot results.
Keywords: Plot, Communication, Interval
References: None |
Problem Statement: When I import a type library into my current Aspen Plus Dynamics simulation, I get a message that my variable types may be overridden. What does that mean? | Solution: This message You have changed the unit of measurement for individual variables. Do you want to override these changes? occurs when you import the new library into an existing flowsheet where you have changed the units of measurement for some of the variables displayed in forms and tables.
If you choose Yes to override the units, the displayed units that you have changed will revert to the types in the library you have just imported. If you choose No, then the unit of measurements displayed will not be affected.
Keywords: Import, UOM, displayed units
References: None |
Problem Statement: PIDIncr Model Supports Vendor Specific Control Algorithms | Solution: Aspen Plus Dynamics now supports some of the key industrial vendors' PID algorithms. The implementation has been given to PIDIncr model within ControlModels. This means the same tuning parameters used in the model can be used directly with the actual controllers (and visa versa). As the model is using the documented algorithms, its behavior should match the real controller behavior. The implemented vendor specific control algorithms and their PID equation types are:
Foxboro algorithm
Proportional only (P)
Integral only (I)
Proportional and Integral (PI)
Proportional and Derivative (PD)
Proportional, Integral and Derivative (PID)
Non-Interacting PID (NI-PID)
Honeywell algorithm
Interactive form Equation A (Interactive A)
Interactive form Equation B (Interactive B)
Interactive form Equation C (Interactive C)
Interactive form Equation D (Interactive D)
Non-Interactive form Equation A (Non-Interactive A)
Non-Interactive form Equation B (Non-Interactive B)
Non-Interactive form Equation C (Non-Interactive C)
Non-Interactive form Equation D (Non-Interactive D)
Yokogawa algorithm
Proportional, Integral and Derivative (PID)
PV proportional and derivative type PID (I-PD)
PV derivative type PID (PI-D)
Note: The Automatic Controller Tuning method does not support these new vendor specific algorithms. For details on this new feature, see PID Algorithms in the on-line help.
Keywords: vendor, algorithm, controller
References: None |
Problem Statement: How to change the gas compressibility factor in Aspen Adsorption | Solution: Gas compressibility factor can only be tracked via Global model for the entire adsorption flowsheet.
By default, gas compressibility is set at “Fixed Compressibility” with a value of 1.
To change this value, go to Explorer > Global > AllGlobals > Z_Global
.
For User Procedure Compressibility option: Z is supplied through a user Fortran subroutine interfaced by the procedure pUser_g_Compressibility .
For User Submodel Compressibility option: Z is supplied through submodel gUserCompressibility .
Keywords: Gas, Compressibility, Global
References: None |
Problem Statement: What is necessary to migrate Aspen Adsim from one version to a newer version? | Solution: If using Aspen Plus/Properties Plus the .appdf will need to be regenerated. The user will need to open the .bkp file they created in Aspen Plus in Aspen Plus 11.1 (if they only have the .apw they will need to go back to Aspen Plus 10.2, open the .apw and then save a .bkp). Re-run the simulation in Aspen Plus 11.1 and save the problem as a .apw file (to ensure the .appdf file is created).
Open the .ada file created in Aspen Adsim 10.2 in Aspen Adsim 11.1. The input file should open normally but may be under initialized owing to initial variables changes in tanks/voids. If underspecified the user should visit each tank/void in turn and invoke its own initialization method (press the Initialize button in flowsheet block's configure form) to rectify the situation.
Open Cycle Organizer. This action will read in the previous cycle description and convert it to the new schema used. It will also regenerate the cyclic task.
Save the input file and the problem should be ready to run.
Keywords:
References: None |
Problem Statement: Customer is getting the following error when attempting to install ADSIM from AES 10.2 Update 1 CD on Windows 98/95 systems;
Error in File F:\AspenADSIM\prop.ini [Aspin ADSIM STANDARD] Validation:
Feature ID ASPEN ADSIM STANDARD is not unique
This only happens on Windows 98 and 95 machines. It works fine on Windows NT and 2000 machines. | Solution: Copy the entire contents of the AES 10.2 Update 1 installation CD onto your Hard Drive.
Replace \AspenADSIM\prop.ini file with the attached version.
Install the product from the Hard Drive by clicking the setup.exe file.
Keywords: ADSIM
Prop
AES 10.2
References: None |
Problem Statement: What are the functionality of various integrator tabs in solver options? | Solution: 1.1 Integration Method
There are four integration methods used in Aspen Plus Dynamics. Integrators are chosen based on the type of model and the objective functions of the run. The selection of this method is a
balance between the speed of simulation and the degree of accuracy of the results. The Figure 1.1 shows the screen shot of Integrator solver options.
Figure 1.1 Screen shots showing different options in integration tab
Four Integration methods are:
1. Implicit Euler
2. Explicit Euler
3. Runge Kutta 4
4. Gear
The option Maximum order is only available when Gear method is selected (Figure 1.2). One of the important advantages of Gear method is that it is based on auto-adaptive algorithm which can select step size automatically and change orders. This option lets you specify the truncation error order of the gear method to avoid unwanted preciseness.
Figure 1.2 Screen shots highlighting Gear method and active Maximum order
The maximum order of error for the Gear method is 5 by default. This method is well known for its applicability in Batch distillation rigorous calculations. In case of all other method, you will find this option unavailable. For Runge kutta 4 method, the order of the error is fixed to 4. For implicit/ Explicit Euler method, the order of error is 1. Please note that this error is generated due to local truncation of Taylor series expansion.
1.2 Error Tolerances
Error tolerance is only accounted into the simulation when the step size is variable. The Figure 1.3 shows the screen shot of the various error tolerances and their default values. Integration step size in any numericalSolution is accepted based on the following two important conditions:
(1)
(2)
Where RTOL= Relative integration error tolerance, ATOL= Absolute integration error tolerance, RtearTOL = Relative tear tolerance and AtearTOL = Absolute tear tolerance (For the definition of other variables, please find in help topics)
The relative and absolute integration tolerances are setting into the solver options to get accurateSolution. The lower you set, the higher the probability of getting accurate results. However, you may need to balance between accuracy and speed of the run.
Figure 1.3 Screen shot of Error tolerances
Tear tolerance is set into solver to determine if a tear is converged. You should be able to control tearing options by setting tearing in option sheet. The tearing option displayed from the mode box enables you to control the tearing. In the case of initialization, all equations are solved simultaneously. To make this task easier, Aspen Modeler applies the decomposition to break down the sets of equations into groups. Each group of equations is then solved in sequence. The degree to which the equations can be broken down into groups depends on the nature of the simulation. Typically, simulations with recycles require more of the equations be solved together in one large group.
Aspen Modeler calls each torn procedure once at the start of the simulation with the initial values of input variables. Aspen Modeler then fixes the procedure outputs to those calculated during that call. They become, in fact, fixed variables. The remainder of the simulation is then solved as normal. After this, Aspen Modeler compares the original procedure outputs with those from the latestSolution. If these are the same to within a tolerance, the simulation is converged. Otherwise Aspen Modeler updates the new procedure output values, and the process is repeated until successive procedure outputs are the same. A steady-state or initialization simulation solved with tearing gives the same results as a simulation solved without tearing. Tearing only affects the ability to find theSolution and the time taken to reach theSolution.
For a dynamic run, using Gear method, torn procedures are converged at initialization and re-initialization. However using Implicit Euler or RK4, torn procedures are not re-converged after initialization.
In simulations, during parameter estimation, dynamic optimization with sensitivities, variable integration step method is used. It is recommended (and it is the default) to include a sensitivity error at each integration point to make sure that the sensitivities are accurate to within the integration error tolerances (Figure 1.4). When the sensitivity integration errors are greater than the integration errors in your flow sheet variables, then the current integration step size will be cut and a new integration step will be considered.
Figure 1.4 Screen shots highlighting Include sensitivity errors and Re-converge torn variables
In some extreme cases, the integrator step can become very small due to repeatedly sensitivity integration error failures (set the solver reporting level to high and look for step rejected due to sensitivity messages in the Simulation Messages Window to see if this is occurring in your simulation). In these cases, it may be appropriate to clear the include sensitivity errors check box to improve performance. However, this may affect in the dynamic estimation or optimization simulation.
1.3 Step Size
Step size can either be Fixed or Variable. For variable step size, you should choose minimum and maximum steps based on the degree of accuracy desired. It is better to avoid the situations where discontinuity occurs.
Figure 1.5 Screen shot of step size highlighting fixed step.
For example, phase changes in property data and/or sudden spike in flow system may need to handle in order to avoid unrealistic discontinuity. Too large value of minimum integration step may introduce inaccurate results. Integrator can not go below the minimum step size even if the integration error is above the tolerance.
If the check box always enforce minimum step size is checked, integration can never go below the minimum of step size (Figure 1.6). When the check box is cleared (default), the integrator can go below the minimum as an attempt to recover and continue integration if there are repeated convergence failures.
Figure 1.6 Screen shot of step size highlighting , always enforce minimum step size and interpolate communication time.
When interpolate communication time is checked, the variable values at communication times are calculated using interpolation. Other wise, the simulation will cut in integration step to coincide with communication time to give most accurate result.
1.4 Event Handling
We have several check box on event handling (Figure 1.7). By checking check box, Local model discontinuity (to determine, IF and switch statements changes the branch) It is possible to locate discontinuity within the model within the discontinuity tolerance, step to that point and restart the integrator.
Figure 1.7 Screen shot showing various tabs of event handling
You have options here to include your discontinuity tolerance limit. When this check box is cleared (default), model discontinuities are not located and the integrator simply steps over them. When Re-initialize after variable step-change check box is selected, re-initialization is performed after the variable step change. If it is cleared, the integrator resumes with a fixed step size. Step size is selected either from initial step size or previously used step size. In event handling, you can specify integration errors or tear integration errors. This will help specify the number of variables that gives largest contribution the integration error. This information is important for diagnostic purposes.
Keywords: None
References: None |
Problem Statement: Best Practices to handle Electrolytes model in dynamics | Solution: Following are the tips, one may consider to handle convergence issue in dynamics:
1) If possible use apparent method. Since electrolyte systems are non-ideal, you may need to switch from the default of local properties calculations to full rigorous property calculations.
2) If you do not need to handle salt or solid precipitation, do not include salt in electrolyte chemistry.
3) Reduce the default integration step size.It may make the model little slower. Since, non-linearity of model may give you inaccurate results or may create convergence problem with bigger step sizes.
4) Reconcile the streams in aspen plus before exporting to dynamics
5)If you configure sensor to add additional properties, make sure model initialized correctly.
For example, If you add pH as a sensor property, you may need to investigate that you have H+ or OH- ions in the system. Moreover, you may need to change property options to rigorous.
Keywords: pH, Nonlinear, Property Options
References: None |
Problem Statement: s
What is the loading for IO scanning for miscellaneous and PID data in AspenWatch? | Solution: Once the miscellaneous and PID data are added in AspenWatch maker, the application created IOget records in Infoplus.21 database. We can take a look at these records using Infoplus.21 Administrator to determine the IO scaning for these records.
-Go to Start>All Programs>AspenTech>Aspen Manufacturing Suite>Apsen Infoplus21>Infoplus.21 Administrator
- Click on the Data_base_name>CIM-IO>IODEVx>Get Transfer, it will show all the get record associated with the CIM-IO device IODEVx.
-The IOGet record starts with AW_G is for miscellaneous data. Click on the name of the record to see the settings and status. Click on the green box with the word IO_#TAGS will show the individual miscellaneous tags and its status.
-The IOget records start with AW_P are used to get PID data. The IO_FREQUENCY parameter show how often the tags in this record are being scanned. The point also shows various statictics of the IOget record. Click on the green box will show the individual tags that being scanned with these record.
-Notice certain parameters of the PID loops are being scanned at different periods. The last IOget rccord has a period of 168 hours which means that those parameters are not scanned on the regular basis.
-Anytime the PID loops are put in config mode in AspenWatch maker, all the parameters are scanned and updated regardless of the IO_FREQUENCY settings.
Keywords:
References: None |
Problem Statement: Where can I find the RadFrac model in the Aspen Plus Dynamics Model Libraries toolbar? | Solution: RadFrac is too complex a model to be created and converged within Aspen Plus Dynamics. For this reason we exclude the RadFrac model from the Model Libraries toolbar.
The complex nature of the model needs to be solved using the Aspen Plus Sequential ModularSolution method. The results can then be used to initialize the Aspen Plus Dynamics Equation Oriented RadFrac model.
Keywords: RadFrac, Model Libraries
References: None |
Problem Statement: Many of the normal stream properties like viscosity are needed for process monitoring or control. The normal stream results or stream sensor does not provide this additional information. Is it possible to calculate these additional properties and then use them as input to process control schemes? | Solution: Additional properties can be calculated using property procedures. A list of the available property procedures can be found in the Aspen Plus Dynamics on-line Help (Aspen Custom Modeler Contents) under Library
Keywords: Stream properties
Property procedures
References: | Property Procedures. One of the property procedures available is pVisc_Liq which calculates the liquid viscosity of a stream. In the following example, this procedure is used to calculate the viscosity of the exit stream of a mix tank that is combining a separate WATER and a GLYCERIN streams.
The calculation for the PRODUCT stream viscosity is done in the Flowsheet Constraints section of the model. The viscosity is fed into the input of a dummy Lead-lag control block that is used to represent the viscosity analyzer. The output of the analyzer is connected to a PIDIncr controller that manipulates the make-up water flow to maintain a specified PRODUCT stream viscosity.
This example simulation is available for release 2006.5 and V7.1 in the attached zip files. The BKP file is also enclosed in order to rebuild the appdf file for different versions of Aspen Plus Dynamics. |
Problem Statement: How to Embed Simulation case in Aspen Simulation Workbook | Solution: Embed feature will keep the simulation case file along with the excel file. So whenever user forward the ASW excel file, it will contain the simulation case file.
To embed the simulation case files:
1 Open the ASW Organizer; select the Configuration | Simulations view.
2 Select the simulation case to be embedded.
3 Click the Add Case button on the toolbar, and browse to the desired simulation case.
4 After selecting the desired simulation case (in this example: testprob.bkp), click the Import/Embed case button and the simulation will be embedded.
Important Notes:
1. Aspen Simulation Workbook can only embed a single file per case into Excel. When using Aspen Plus, save the Aspen Plus case using the compound file option to ensure all of the required dependent files are available.
2. ASW file embedding cannot be used with Aspen Custom Modeler files which require APPDF files that cannot be embedded into the simulation case file. This includes Aspen Plus Dynamics files that use RGIBBS, closed-form Polymers Plus reaction models, or user reaction or property models written in FORTRAN and compiled as DLL files.
Keywords: Embed, Excel workbook, Simulation.
References: None |
Problem Statement: APC Builder reinsall fails after installing its cumulative patch.
And, got following error message.
1311 Source file not found E:\aspenONEV7.2DVD2\ams\aspenonev7.2dvd2\Aspen APC Builder\GLE28E~1.cab. verify that the file exists and that you can access | Solution: The root cause for error
1311 Source file not found E:\aspenONEV7.2DVD2\ams\aspenonev7.2dvd2\Aspen APC Builder\GLE28E~1.cab. verify that the file exists and that you can access
is because this missing component is newly added in patch, so when you use RTM DVD to re-install(repair) it can't find the component which was not existed in RTM DVD.
The resulting behavior is likely expected for the steps described below.
Once a cumulative patch has been applied to a base software version via the aspenONE Update Agent utility, the Repair operation using the original (same base version) DVD is not realistically valid for the patched software. This would create file version mismatch instances because the upgrade/repair option using the (base) DVD would attempt to install older software/file versions than the patched installation, and would not facilitate correct file replacement ? potentially resulting in software errors, MSI repair, etc.
Keywords: repair
cumulative patch
1311 Source file not found
UPDATE
References: None |
Problem Statement: When a Process Model has been identified, why does it appear that the PID-Watch Expert parameters are not working? | Solution: When setting the Expert parameters take care that the desired value is properly registered in the box (the value selection works better if you move slowly the slider).
For example, the Beta parameter is showing 69 in the box even if the slider is 12.
Double click the slider selector to adjust it to the right value. Hit OK to save your selected values.
Go back to the PID Tuning Specification Parameters window and check that the specified values are still shown there. In the PID Tuning window hit the `Run? button and the simulation will appear.
This is a behavioral issue for the Visual Basic slider bar control (and not a deficiency in the software code). When the slider is moved at a reasonable speed, the slider bar and value shown in the adjacent text box should align at the same values. When the slider bar setting and edit box value are in agreement the changes in the Optimized tuning and respective Calculated PID Response plot will appear.
Work around: Use directly the edit box, this should move the slider bar correspondingly.
Keywords: PIDWatch, Expert Parameters
References: None |
Problem Statement: Dynamic models with pipes could be a challenge to tune up. | Solution: Here are some general tune up tips to help with pipe model trouble shooting:
1. In pipe model, the first node and the end node boundary conditions are being swapped based upon the flow direction, but they swap independently. This is generally good approach to handling pipe in rigorous manner. However, it may cause trouble when the number of interior nodes are insufficient. Thus providing more nodes can help robustness in convergence.
2. Prevent boundary condition swapping from flow-direction change. By default, the software does that. But for single phase and/or single component systems, it might worth to try to stop boundary condition swapping. Here is procedure:
a. Open a case with pipes in AD
b. Go to a pipe's context menu (right click)
c. Open Advanced table
d. In Advanced table, set PDEReverse = No, which means no boundary condition swapping at all.
3. Const_dp_dL method means no holdup modelling and no interior discretization for the pipe. It is indeed instantaneous steady-state type pipe model. Pressure drop is still available, but not in rigorous way, it uses average <acceleration>, <frictional>, <elevation> values that evaluated at inlet and outlet points. The following are the model equations:
// pressure drop
Out_P.P = In_F.P - P_drop;
IF (In_F.F >= 0) THEN // forward flow
Pdrop1 = dp_fr_in + dp_elv_in + dp_acc_in;
Pdrop2 = dp_fr_out + dp_elv_out + dp_acc_out;
ELSE
// use -ve pressure drops to trick pcalc(*) submodel A+ procedures
-Pdrop1 = dp_fr_in - dp_elv_in + dp_acc_in; // elevation term independent of flow direction
-Pdrop2 = dp_fr_out - dp_elv_out + dp_acc_out; // elevation term independent of flow direction
ENDIF
// average total pressure drop
P_drop = (Pdrop1 + Pdrop2)/2;
4. Review overall piping model, identify troublesome section and only apply PDEReverse = No there.
5. Use a vessel to model holdup for those troubled pipe sections.
6. Evaluate whether a pipe model could be simplified and substituted with a valve model.
Keywords: Pipe, Swap, Holdup
References: None |
Problem Statement: New 'Cycle option for TimeData model | Solution: The option enable the model to repeatedly cycle through the data. To activate, set Cycle to Yes on the configure form.
See attached model file to check the cycling data output from the TimeData block.
Keywords: TimeData, Cycle, Cycling
References: None |
Problem Statement: Is there a sample to show column shutdown? | Solution: Run the attached model and let it fully running and then simply change feed controller to be manual and fill in its OP to be zero, then observe that all the flows of the column come to zero eventually.
Note: The model file is taken fromSolution 115731
Keywords: shut down, shut
References: None |
Problem Statement: Why are variables unable to be removed or added when running MQA cases for Adaptive Modeling? | Solution: When setting up a MQA case on PCWS, the list of Independents and Dependents variable are set and can not be changed.  The Add and remove variables are grey out along with the time to SS and Max model order.
This is by design as the MQA utilizes the whole model structure to run its analysis. However you can temporarily disable some MVs or CVs from the analysis by selecting the variable and click on the Options button. A pop-up window appears where you can disable that variable for the current case. Once disabled, the variable will have a (X) indication next to its name on the list. After the case is run, the result still shows a full model however, the MQA results are calculated on the variables that are enabled for the analysis. The disable variables are left blank (grayed out).
Keywords: MQA
Adaptive Modeling
References: None |
Problem Statement: Why do I get Error (-1) saving CCF to disk, while saving a controller configuration file (CCF) using Aspen DMCplus builder when selecting the option to not validate using DMCplus Simulate? | Solution: This error is related to permission of the folder C:\ProgramData\AspenTech\APC\Online\app\controller folder, where the CCF is always placed for loading a DMC plus controller online. The ProgramData directory in Windows requires that the user writing to this directory has Administrator privileges.
Hence, if you require saving the CCF without validating using Simulate, there are two options:
1. Launch Aspen DMC plus Build using Run as administrator. Navigate to File-> Open-> CCF name. Before closing, select No for validation with DMC plus Simulate. This time CCF can be saved without any problem.
2. Copy the CCF from C:\ProgramData\AspenTech\APC\Online\app\controller folder and place it in any other folder. In this case, saving the CCF without validating using DMC plus Simulate will also save the CCF without any errors.
Keywords: Error (-1)
DMCplus Simulate
DMCplus Build
CCF error
References: None |
Problem Statement: Is it possible to import an existing DMCplus Model DPP file into APC Builder? | Solution: Currently there is no direct way of importing a DMCPlus Model project file (.dpp) into an APC builder project. Here is a list of recommended steps for converting a DMCPlus project file into a APC builder project.
1. Export items from a .dpp file and then import them into a APC builder project. The following list is the recommended items to be transferred from .dpp file to APC builder:
· Vectors
· Vector Lists
· Cases
· Models
· Global Slices
2. Manually Duplicate any calculated vectors along with any transformations. All such data would be lost on import.
3. Re-run all the imported cases.
4. Rebuild the master model with the appropriate curves from various cases manually.
5. Verify the rebuilt model by comparing it to the imported DMCplus model.
Keywords: APC Builder
DMCPlus .dpp
References: None |
Problem Statement: What are the common log files associated with APC Builder controllers? | Solution: There are mainly four location where error logs are stored for APC Builder applications that are running online-
1. On Web Server, Repository Errors.log: Located in the folder C:\ProgramData\AspenTech\APC\Web Server, this file logs all messages related to the controller application on the Web Server. Ex.: Deploy success and failure, Bad controller structure causing controller to disappear on the web, etc.
2. On Watch Server, Repository Errors.log: Located in the folder C:\ProgramData\AspenTech\APC\Performance Monitor, this file logs information relating to any failures with AW collection for the non-linear controller application.
3. On APC Online Server, NodeRepositoryErrors.log: Located in the folder C:\ProgramData\AspenTech\RTE\V8.7\Clouds\Online\sys, this file logs information on deploy issues on the APC Server side (messages related to situations where the controller doesn't even show-up on the Web interface).
4. On APC Online Server, Event Viewer Logs: This is the standard windows Event Viewer, APC Builder related messages show up in Windows Logs | Application, while online controller related messages show up in Application and Services Logs | RTE .
Keywords: Log files
APC Builder
Online Application
References: None |
Problem Statement: Possible range of values for DEPSTA and INDSTA are different in APC Builder compared to DMCplus. | Solution: Engineers need to keep this difference in mind while reviewing the calculation for an application converted from DMCplus to APC Builder. The following table lists the possible numeric values for the status parameter of dependent and independent variables in the controller and the difference between how the numbers are interpreted in APC Builder vs DMcplus.
APC Builder (Service Status for Dependents)
DMCplus (DEPSTA)
-2
Eng OFF
Eng OFF
-1
Failed
Bad
0
OFF
Good
1
ON
PRED ONLY
2
PRED ONLY
USE_PRED (Use Predicted value)
3
Not available
MAINT_PRED (Maintain predicted value, use neither value nor prediction)
APC Builder (Service Status for Independents)
DMCPLUS (INDSTA for MV)
-2
Eng OFF
Eng OFF
-1
Failed
Bad
0
OFF
Good
1
ON
PRED ONLY
2
Prediction
USE_PRED (Use Predicted value)
3
Not available
MAINT_PRED (Maintain predicted value, use neither value nor prediction)
Note – INDSTA for a FF in DMCplus involves only 3 possible values, -2, -1 and 0 which correspond to ENG_OFF, BAD and GOOD respectively.
The Calcscript program in APC builder has built-in formula functions. These built in formulas provide a quick way to convert the calculations within a controller application from ccf format to APC builder calcscript format. However, it is extremely important to review these calculations and ensure that the correct conversion code is being used.
Please see an example in the image below where we show how the ccf_to_status formula in APC Builder converts the ccf calculation for the DEPSTA parameter.
ORIGINAL CODE
However the code is missing lines about the situation where the service status could be a value of -1 or -2. The code needs to be modified to include the following lines.
PROCEDURE TO ADD REVISED CODE
1. Configure DMCSTAT user entry for Independents and Dependents
2. Add the following calculation code in an input calculation line (Calculation name: SETINDSTA)
' Convert APC Service status to INDSTA
' Service Status = -2 then ENGR OFF
' Service Status = -1 then BAD
' Service Status = 0 then IGNORE
' Service Status = 1 then GOOD
' Service Status = 2 then PRED ONLY
' INDSTA = -2 then ENGR OFF
' INDSTA = -1 then BAD
' INDSTA = 0 then GOOD
' INDSTA = 1 then PRED ONLY (FFW)
' INDSTA = 2 then READY
if (SERVICESTAT = -2) then
INDSTS = -2
end if
if (SERVICESTAT = -1) then
INDSTS = -2
end if
if (SERVICESTAT = 0) then
INDSTS = -1
end if
if (SERVICESTAT = 1 and DMCON = 1) then
INDSTS = 0
end if
if (SERVICESTAT = 2) then
INDSTS = 1
end if
if (SERVICESTAT = 1 and DMCON = 0 then
INDSTS = 2
end if
3. Add the following calculation code as an input calculation line (Calculation name: SETDEPSTA)
' Convert APC Service status to DEPSTA
' Service Status = -2 then ENGR OFF
' Service Status = -1 then BAD
' Service Status = 0 then IGNORE
' Service Status = 1 then GOOD
' Service Status = 2 then PRED ONLY
' DEPSTA = -2 then ENGR OFF
' DEPSTA = -1 then BAD
' DEPSTA = 0 then GOOD
' DEPSTA = 1 then PRED ONLY (FFW)
' DEPSTA = 2 then USE PRED
' DEPSTA = 3 MAINT_PRED
if (SERVICESTAT = -2) then
DEPSTS = -2
end if
if (SERVICESTAT = -1) then
DEPSTS = -1
end if
if (SERVICESTAT = 0) then
DEPSTS = -1
end if
if (SERVICESTAT = 1 and DMCON = 1) then
DEPSTS = 0
end if
if (SERVICESTAT = 2) then
DEPSTS = 1
end if
if (SERVICESTAT = 1 and DMCON = 0) then
DEPSTS = 0
end if
4. Move IO tag from Service Status to DMCSTAT for Inputs and Outputs.
Following the above recommended steps would help in configuring APC Builder to consider DEPSTA or INDSTA in all possible scenarios.
Keywords: APC Builder
Internal Calculations
Calcscript
DMCplus Conversion
References: None |
Problem Statement: Why do I get an Overwrite formulas Warning Message in HYSYS with Aspen Simulation Workbook (ASW)? | Solution: When accessing HYSYS variables whose calculate state is adjustable in ASW, sometimes you can receive warning messages asking if you want to overwrite formulas with constant values. The ASW variable status of these variables is shown as Default. These variables are calculated but can also be modified by users. ASW can try to update these variable values in HYSYS, causing the warning message that is seen.
To prevent this from happening, set the Read-Only status of these variables to True in ASW. This will prevent ASW from trying to write these variables back into HYSYS.
Keywords: None
References: None |
Problem Statement: What can cause the error DMCINI Failed - 50 and how to solve it? | Solution: When the internal validation fails it gives you the “DMCINI Failed -50” error. This error will appear when you try to load a ccf or when you save your ccf and validate it with DMCplus simulate.
There are several causes for this problem, please review your ccf in order to avoid them.
1. If you have input/output calculations in your controller don’t use “String” tags.Solution 136839.
2. Avoid writing in your calculations to hardcoded parameters like WFAILM
3. If you have a piece-wise linear transform on a variable and it is not monotonically increasing - i.e. two Y-points had the same value, the validation will fail. From the DMCplus Help Topics, the interpolation formula is as follows:
The x-y pairs used to specify the transform must be monotonically increasing. In other words:
· x2 must be greater than x1, and x3 must be greater than x2...
· y2 must be greater than y1, and y3 must be greater than y2...
...and so forth.
4. Check if you have user define variables in use by your calculation that does not exists (In V7.3 the debugging process will catch this errors during the validation)
If you are still getting the error after the above recommendations please send the ccf and mdl file of your application to Aspen Technical Support.
Keywords: DMCINI
APC Manage
DMCplus Builder
DMCplus Simulate
References: None |
Problem Statement: FAQs on using AspenOTS as an OPC server for a virtual Hysys simulation and connecting it to DMCplus. | Solution: What is the procedure to setup an OPC server for a virtual plant Hysys simulation?
You will first need to set up the tags in the OTS application using the HYSYS model that you are working with. You can follow the steps listed inSolution ID- 128009 to add the tags to the OTS application. Once you finish adding tags, you can go ahead and configure the OPC server you would be working with. TheSolution (128009) illustrating using MatriconOPC. However, if you have CIMIO for OPC on the OTS, machine, you do not need to set up the tags in MatrikonOPC as AspenOTS itself acts as an OPC server. Check the Services file located in C:\Windows\System32\drivers\etc to confirm that a service has been defined for linking OTS with the OPC server. The port number used is 60019. In case you do not see any service associated with such a port number, you will need to manually configure your OPC server for OTS applications. Follow the steps listed below to configure the OTS OPC server-
1. Browse to Start/All Programs/AspenTech/Aspen Manufacturing Suite/Aspen Cim-IO/Servers/CIM-IO for OPC/ and select CIM-IO for OPC Properties. This should open up a window as shown below.
2. Click the Configure OPC Servers option. This brings up the OPC Manager Configuration window.
3. Select Add Server icon in this window, fill in the following information and click OK.
4. You should now see AspenTech.OTS_OPCServer on the right hand panel of the OPC Manager Configuration window, indicating that see AspenTech.OTS_OPCServer has been added to the startup servers list. Adding the OPC Server to the startup list should automatically update the Logical Devices and the Services file.
5. Open Logical Devices definition file from Start/All Programs/AspenTech/Aspen Manufacturing Suite/Aspen Cim-IO/ and confirm that you see the logical device IOOPC listed for the CIOASPENTECHOTS service.
6. Open the Services file from C:\Windows\System32\drivers\etc and confirm that you see the CIOASPENTECHOTS service listed at the end of the list, configured using port number 60019.
In one of the sample case (DMC Sample case in Hysys,Solution ID # 120540) on the support site, it says that you will need SLM_Hysys_DMCLink to establish the communication. Are both methods used for communication, one using the link & other using OTS & OPC?
No, each method is specific to theSolution. DMCLink forSolution ID- 120540 and OTS forSolution ID- 135453.
Do you need additional AspenOTS Framework license to establish the communication? If so, can you tell me what additional licenses I will require to establish the communication?
Yes, you will need a license for Aspen OTS Framework in order to use the procedure listed inSolution ID- 135453. This particularSolution does not really link DMCplus to HYSYS but actually lists the procedure to use the Hysys simulation to serve as a virtual plant. Basically, the DMCplus controller thinks that it is getting the data from an actual plant and not a simulation. When using thisSolution, you do not need to enable the option for DMC/DCS link in the hysys simulation. I would therefore guess you do not need the SLM_Hysys_DMCLink in your license file. You however will need SLM_OTS_Framework in your license file. To summarize, depending on theSolution you choose to use, you will either need SLM_Hysys_DMClink (Solution ID- 120540) or SLM_OTS_Framework (Solution ID- 135453).
Clarification FAQs
Consider a case where the set-up comprises of two machines, one which will host Aspen Hysys model and another will run Aspen DMCplus controller. The questions and answers below clarify the steps to be executed to establish the communication
Aspen OTS framework to be installed on the Aspen Hysys model computer and expose the tags for OPC communication.
Yes, this is correct.
Install Matrikon OPC explorer get the tag names on the same machine.
You can choose to use Matrikon OPC explorer, but you can also do without it. OTS provides a connection between the Aspen HYSYS simulation and an OPC server (which resides with the OTS). You can configure the new OPC server using the procedure listed in my previous email (email body itself).
Install CIMIO for OPC on the model computer.
You need to have CIMIO for OPC on the HYSYS/OTS machine and the Cimio client on the DMC machine. You however need to make sure that you configure the Logical Devices file and the Services file on both the HYSYS/OTS machine and the DMC machine.
Aspen OTS will be linked to the tags in the DMCPlus controller & communicate using CIMIO for OPC.
Yes. This is correct.
Does Aspen OTS Framework will work as a OPC server?
Yes. Aspen OTS Framework acts as the OPC server. You however need to configure it using the procedure listed in ?What is the procedure to setup an OPC server for a virtual plant Hysys simulation??
Keywords: Aspen OTS
Hysys Virtual Plant
DMCplus
References: None |
Problem Statement: How can I turn on the column grouping feature in the Variable Organizer? | Solution: To turn on the column grouping feature, right click on a column name in Variable Organizer and select the Group Box option. This will make the column grouping box visible. You can then drop columns headings into the box to group your data by those columns.
Keywords: None
References: None |
Problem Statement: Before v7.1, to model detailed column overhead, one had to do it in Aspen Plus first and then export to Aspen Dynamics. | Solution: Since v7.1, Aspen Plus Dynamics.can automatically reconfigure a Radfrac column with a condenser into an external condenser.
Key benefits of an external condenser
1. Allows detailed modeling of the overhead system without having to configure it in Aspen Plus (which may be difficult to converge). Use only the Radfrac block in Aspen Plus and then use this new feature to expand the overhead system. You can then add pumps, heat exchangers, etc. to expand the overhead system
Note: Adding instantaneous models in standalone dynamics is straightforward if you set flashbasis to procedure).
2. Allows detailed control system to be modeled, accessing the PVs/MVs in the expanded overhead system.
To use this feature select ?External_Condenser? from the column scripts menu. (See the image below.) This results in a fully specified multi-block Radfrac model with an external condensro. No additional initialization efforts are required.
To see the example, load attached Aspen Plus model, run and expert as flow driven dynamics. Then in Aspen Dynamics, right click on the RadFrac block, go to Scripts and then select external condenser.
Please note that the feature is v7.1 onward and the model file is in v7.1 format.
Keywords: Script, external, condenser, expansion, overhead, column
References: None |
Problem Statement: Tips on how to properly set up Subspace ID to get best model. | Solution: - Keep the case small. Include similar dynamics CVs and relevant MVs only. The 'kitchen sink' approach will not work here. Set up a larger case and run it as FIR ID to get a rough idea of what the model is going to be.
- Add .PV of the MVs (assuming you are moving the .SP) will help ID the other CVs in the case. Additionally, you can check the .SP vs .PV model, which should be around 1.0000.
- Bracket the case close the 'correct' TTSS. If you think the TTSS is 90, add only two more cases, 60 and 120.
- Maximum order is important, so set it between 20-35. If the optimum order is within 3 of the maximum order, increase the maximum order (if it is still low) or split the CVs up to two or more cases and re-run it/them again.
- Any dead time adds an order to the model order. So for large dead-time, shift the CV first before running the case. You can include both the shifted and un-shifted vectors in the case.
- If the subspace model has a fast cycle, inspect the raw data for any valve cycling in the data. Reduce the max order or filter the noisy CV before using it in the case.
- If the plant test data includes any intermittent cycle such as analyzers, central averaging the signal to 1.5 the update time to remove the stairs step effect in the data.
Keywords: subscape ID, Maximum order.
References: None |
Problem Statement: What does the following error message mean : a??Entry name: is invalid for one of the following reasons: a) it conflicts with a reserved entry name, b) it is not allowed in this section, c) it is already in use by another entry Please select another namea??? | Solution: This warning message appears in V7.3 CP4 and V8.0 when an Entry offends one of the three mentioned conditions.
Some examples:
If a new Entry in the Independent Section is named as ETMV (with the External Targets disable) the error message will appear. In this case the condition a) it conflicts with a reserved entry name is not met. The ETMV is a reserved entry available when the External Target box is checked.
If a new Entry in the Dependent Section is named starting with GMULT the error message will appear. In this case the condition b) it is not allowed in this section is not met. The DMCplus Entry Dictionary explains that GMULT applies only for the Independent Section.
Keywords: DMCplus Build, Entry
References: None |
Problem Statement: What is the proper technique to identify the model response curves of an intermittent signal? | Solution: Intermittent variable is any measurement that does not have continuous measurements (every collection cycle). The most common example of an intermittent variable is an analyzer reading. Raw values of intermittent variable should not be used directly in model identification because it may lead to model errors caused by the algorithm trying to fit the model into the 'stair-step' type data/signals.
The proper way of using the intermittent variables in a model ID is to use CAV (center average) filter with the number of samples used in the filter being equal to the number of data points in about 1.5 times the analyzer update cycle time and then a small exponential filter to smooth out the edges.
Keywords: Intermittent Variables
Model Identification
References: None |
Problem Statement: What is a Pseudo ramp variable and its example with respect to DMC plus controller? | Solution: A Pseudo Ramp variable is that process variable which has either very long (10-12 hours) or very short (<30 minutes) Time to Steady State (TTSS).
These variables, due to a gross difference in dynamics w.r.t other variables, will be modeled & controlled as a ramp variable in Aspen DMC plus system.
It is Pseudo ramp because, actually it is a normal variable. But as Time To Steady State is too long/ too short, and if we don't mark the variable as Pseudo ramp, it will be difficult for controller to decide the move plan & hence control will become sluggish or inaccurate.
Any variable can be defined as Ramp or Pseudo ramp through Aspen DMC plus Model, while defining vectors as Independents & dependents.
Example Pseudo ramp variable:
Let us say we have a scenario where we have composition in a column which has very high settling time, like 12-24 hours. We have some flooding dynamics which will be 1-2 hours (settling time) & valve output as a variable whose settling time is <30 minutes.
So, in this case where both very long & very short time to steady state exist in same system, the variable with very long time to steady state (composition in our case), will be marked as Pseudo ramp variable in Aspen DMC plus Model.
Key words
Pseudo ramp variable
Ramp variable
DMC plus model
Example of Pseudo ramp
Keywords: None
References: None |
Problem Statement: What is the significance of selecting Time to Steady State in case parameters, while creating a controller model using Aspen DMCplus Model package? How do I judge whether the selected Time to Steady State is correct or not? | Solution: Time to steady state (TTSS) is the time in which Control Variable (CV) reaches to steady state, after one unit movement of the Manipulated Variable (MV). In other words, it can be said that this is the time in which the whole process/system settles down, once after there is a change in MV.
While creating a controller model using Aspen DMC plus model package, time to steady state has to be provided for the specific case. Selection of TTSS is based on the process history data and information from plant persona/operators. Generally, this time is from 60 minutes to 120 minutes. It can be more or less that these values as well.
How to understand whether selected TTSS is correct or not:
For example, a case with built with 4 time to steady states i.e. 30 mins, 60 mins, 90 mins & 120 mins. After running the case, case plots comparison for all 4 TTSS will help to understand the effect of all times on process/system.
If TTSS is too small, then the model gain will not be correct as in less time, less data points will be captured, due to which the CV response for an MV movement will not be correct or reliable. On the other hand, if TTSS too long, controller action will be sluggish. This is one method to understand whether or not the specified TTSS is correct.
Another method to understand whether a correct TTSS is specified or not is, while using Finite Impulse Response identification method for controller model building, we get two curves, one smooth (with smoothing factor 5) & one un- smooth (with smoothing factor 0). So, ideally (with correct TTSS), these two smooth & un smooth curves should be running simultaneous to each other. But if a larger TTSS has been selected, the smooth & un smooth curve will drift apart from each other, and hence it is easy to identify that this TTSS is much longer that what is actually required.
Note:
1. A default value of 5 is used as Smoothing factor in DMC plus model.
2. Smoothing factor is only used for Finite Impulse Response identification method, for Aspen DMC plus model.
Keywords: Time to Steady state, TTSS, DMC plus model, Smoothing factor
References: None |
Problem Statement: When you have multiple ASW versions installed on your computer, it could on certain occasions generate some incompatibility issues between the Add-in that is installed in Microsoft Excel. This is especially so when trying to create macros and link path commands to work in a created workbook. | Solution: In order to avoid this issue, follow the procedure suggested below:
1) Remove the entire list of ASW Add-in versions running Excel using Administrator rights.
2) Once the program is running, under File | Options | Add-ins | Manage | COM Add-ins, click on ‘Go…’ and select from the list all the ASW Add-ins installed on the list. Then, in order to be removed, click the ‘Remove’ button.
3) Then, close the program and repeat the steps 1) and 2), but in this case click on the ‘Add…’ button, in order to include the correct ASW Add-inn from the following directory:
X:\Program Files (x86)\AspenTech\Aspen Simulation Workbook VX.X\
4) Under Start | All Programs | Aspentech | Process Modelling VX.X | Aspen Simulation Workbook | Aspen Excel Add-in Manager VX.X and double-check that the correct ASW Add-in version has been selected and active.
5) Now the macros and the path link commands from previous workbooks will work fine using ASW in the updated version.
Keywords: Add-in, Macros, Path link.
References: None |
Problem Statement: What are the possible source of model errors during model Identification? | Solution: During the model identification process, there are two types of model errors:
- Variance errors
· caused by noises and unmeasured disturbances in the test data set
· these errors can be reduced or eliminated by adding more step test data of high quality (high Signal/Noise Ratio) to the dataset used for model identification
- Bias errors
· caused by deficiencies in test data (cross-correlation, auto-correlation, feedback correlation). These can be mitigated by adding more high quality (high S/N ratio, lower or no MV correlation, lower feedback correlation) step test data for model identification.
· Deficiencies in model structure (missing independents, non-linearity, valve saturation). These errors will not reduce with more step test data. The only way to reduce the bias error because of model structure would be to fix the model structure.
· Model uncertainty plots only estimate variance errors and NOT bias errors. If the predictions are not adequate despite the fact that the model uncertainty plot shows excellent results and the prediction does not improve with additional data, it may be an indication that bias errors exist. Knowledge of the process and engineering judgment are required to eliminate or reduce bias errors.
Keywords: Model ID
Variance error
Bias error
DMCplus
APC Builder
References: None |
Problem Statement: How to troubleshoot Installation and Run Time issues with Open Simulation Environment (OSE) Workbook? | Solution: Installation Issues
ProblemSolution / Notes
After installing Aspen OSE Workbook, the OSE Workbook toolbars do not appear in Excel.
The toolbars may be inactive. In Excel, select View | Toolbars to see a list of the toolbars. Check the Aspen OSE Workbook Design and Aspen OSE Workbook Run toolbars to make them active. If the toolbars are not included in the list, Excel may have disabled Aspen OSE Workbook. Go to the third item in this table.
After installing Aspen OSE Workbook, the OSE Workbook Toolbars are not available in the toolbar list and the ?Aspen? menu does not appear in the Excel pull-down menu structure.
This usually happens if the workbook is not registered correctly and fails to load. This may have occured because Excel was open when the workbook was installed.
Users (running as administrators) can manually register Aspen OSE Workbook using the following command from a DOS window (note: shut down all instances of Excel before running this command):
regsvr32 %CommonProgramFiles%\AspenTech Shared\Aspen OSE Workbook 2004.1\ASWXLAddinLoader.dll
If this fails, Excel may have disabled Aspen OSE Workbook. See next item below.
After installing Aspen OSE Workbook, the OSE Workbook Toolbars are greyed out, and the ?Aspen? menu does not appear in the Excel pull-down menu structure.
The toolbars may have been disabled by Excel. To check:
1. Open Excel
2. Open menu Help | About Microsoft Excel.
3. Click on Disabled Items, if Aspen OSE Workbook appears in the list of disabled items, remove it.
Next, add ?COM Add-Ins?
1. Select Tools | Customize
2. Go to the Commands tab sheet, select Tools under Categories, and Com Add-ins under Commands:
3. In the dialog box, go to the Excel pull-down menu and select Tools to open the Tools menu list. Drag the Com Add-Ins object from the dialog box above into the Tools menu list below Add-Ins item:
4. Select Com Add-Ins
5. Check if Aspen OSE Workbook 2004.1 is in the list.
6. Double check the location is at C:\Program Files\Common Files\AspenTech Shared\Aspen OSE Workbook 2004.1\ASWXLAddinLoader.dll.
7. Double check that the addin is actually checked.
Runtime Issues
ProblemSolution / Notes
When opening Excel, a pop-up menu appears with the message ?This file contains macros with an expired or revoked signature. Since you are running under High Security Level, these macros will be disabled?
Due to an oversight, the Verisign digital signatures used to build Aspen OSE Workbook expired on April 28, 2005.
The only workaround at this time is to lower security to Medium or Low via the Security dialog under the Macros submenu on the Tools menu or to Trust all install addins which is available on the Trusted Sources tab of the Security dialog. The best recommendation is to change the value to Medium security as the machine is still protected. In general it requires the user to allow every addin to run separately.
This problem is limited to Excel 2000.
Keywords: OSE Workbook
Open Simulation Environment
Workbook
References: None |
Problem Statement: I have linked Aspen Simulation Workbook to HYSYS Dynamics. How do get excel to update the profile table once the HYSYS Dynamic run has completed? | Solution: In order to update excel profile during the dynamic run ASW will pause the Dynamic integrator to collect data from HYSYS and then resume the run. Further information into the frequency at which ASW updates the profile table is provided in knowledge baseSolution 144075.
If you want the dynamic simulation to run without pausing and do not need to see results until the run completes or is paused by the user then you can set the simulation property UpdateDuringDynamicRuns to false. This will allow the simulation to run uninterrupted but you will not see updates in Excel until it is paused by the user or reaches a stop condition. The option to set the simulation property UpdateDuringDynamic Runs to false is found through the Organiser|Configuration|Simulations|Solver. A screenshot showing this input is provided below:
Keywords: ASW, HYSYS Dynamics, Solver
References: None |
Problem Statement: How do I select which version of Aspen HYSYS to use with Aspen Simulation Workbook (ASW)? I have multiple versions of Aspen HYSYS in my PC and I would like to select a particular HYSYS version for ASW. | Solution: From Aspen Simulation Workbook, one can control the HYSYS version to be launched.
Please go to the Aspen ASW Add-in in Excel and open the Organizer; then go to Configuration | Simulations. From Version Option in the pane on the right, it is possible to specify (please see the screenshot below):
A? a??Any Versiona??: for allowing to open the default simulator version;
A? a??Minimum Versiona??: for specifying a minimum version of the simulator to be used;
A? a??Exact Versiona??: for specifying the exact version of the simulator to be used.
The specification of the Minimum or Exact Version is possible from the Version String field. See the following examples for setting the Version String:
A? For Aspen HYSYS V8.0, set a??V8.0a??;
A? For Aspen HYSYS V7.3, set a??V7.3a??;
A? For Aspen HYSYS V7.2, set a??V7.2a??.
If one wants to launch specifically Aspen HYSYS V7.3, the proper settings are shown in the image below (Version Option: a??Exact Versiona??; Version String: a??V7.3a??). Please note that the simulation should not be Active when changing these options.
Keywords: Aspen HYSYS Version Selection, ASW
References: None |
Problem Statement: How do you toggle between Aspen HYSYS column specs within Aspen Simulation Workbook (ASW)? | Solution: To toggle between the specs in the column within ASW you have to first bring the specs into the ASW organizer and create a table with in the excel.
Please see below steps for the details:
1. Highlight the Specified Value, Current Value, Wt. Error, Active and Estimate variables in the column monitor page by holding the left mouse button on the top left hand corner and moving it towards the bottom right hand corner.
2. From the HYSYS menu bar select Edit | Copy or press Ctrl+C on the keyboard.
3. From the ASW Organizer Paste Variables From Clipboard in the organizer by clicking on
4. Create a table in excel by clicking on where you can toggle between 0 and 1 for inactive and active specs respectively.
5. In the following image the TEG Regenerator Active specs are shown with number 1 and if you change this number to 0 they will be inactive.
Keywords: None
References: None |
Problem Statement: How to turn off test group in a controller running in Calibrate mode? | Solution: Test Group in Aspen DMC3 controllers represent an handle the user could use to specify whether the variables (belonging to a particular Test Group) should be included in the optimization and control problem or in the Step Testing problem. The system does not allow user to turn OFF a test group (remove variables from both control and optimization problem and the step testing problem) and if the user wishes to turn OFF all variables belonging to a test group, they would need to use one of the two options listed below to achieve this option-
1. Turn OFF Subcontroller: It is typical to have Test Groups configured with the same structure as a subcontroller in the DMC3 controller. If a corresponding subcontroller does exist, the user may switch OFF ON/OFF Request switch for this subcontroller to completely remove the variables from the control algorithm.
2. No subconrollers defined: In case the controller is built without any subcontrollers (or if the subcontroller structure differs from the Test Groups structure), the user will have to manually turn OFF each Independent and Deenpdent variable belonging to the test group in order to take the variables out of the engine calculations.
Keywords: Test Group
Turn OFF
References: None |
Problem Statement: An error is returned when using the type-ahead tag search on the OEE chart page. However, if the tag search for OEE tags is performed on the common Search page, it returns all configured OEE tags. The tags can then be successfully returned to plot and the OEE plot will open.
Search error: make sure search is properly configured in AtWebPlotsConfig.xml and search server (tomcat 7) is running. Also, make sure the login user is in the solr security domain.
Here is an example of a server where type-ahead tag search works: | Solution: The full-screen search page has a different configuration file for defining the search engine connection information than aspenONE Process Explorer page.Â
AtWebPlotsConfig.xml under ProcessExplorer/WebControls defines this information:Â localhost can be used here if Tomcat for the Search Engine is installed on the server. Otherwise, use the fully qualified server node name of the server where Tomcat for the Search Engine is installed. See example below.
The Credentials field should not be changed if the password and username haven’t been changed for Tomcat.
Please compare the above screen capture of theAtWebPlotsConfig.xml configuration file with your configuration file to make sure it is consistent with your environment.
The Search Service used by the full-screen search has its own configuration file, called config.xml:
If the full-screen search works, this file should not be updated.
Keywords: None
References: None |
Problem Statement: In Aspen Simulation Workbook (ASW) how can I change the dynamics update frequency? | Solution: In ASW the user can change the dynamic update frequency through the
Organizer|Configuration|Simulations|Dynamics update frequency. A screenshot showing this parameter is shown below:
By default ASW will update after each time step that is entered through the Aspen HYSYS Dynamic Integrator. The user is able to edit this update frequency through the dynamic update frequency in the organizer. For example, if the dynamic update is left at 0 then ASW will update at the same frequency as the time steps in HYSYS Dynamics. However, if the dynamic update is set at 5, then ASW will update once for every 5 time steps that occur in HYSYS Dynamics.
Keywords: HYSYS Dynamics, ASW, Frequency
References: None |
Problem Statement: What are OEE_QUANTITY_UNITS, OEE_UPDATE_PERIOD, and the target and limit fields used for? | Solution: The OEE_QUANTITY_UNITS, OEE_UPDATE_PERIOD, and the target and limit fields are not used by the current version of the application at all.
· The OEE_QUANTITY_UNITS field is just for reference to record what units the Actual and Target is being measured in.
· The OEE_UPDATE_PERIOD field is meant to indicate how often the OEE metric is being recorded if it is being recorded (the application does not automatically record the OEE metrics).
· The “target and limit fields are not used by the current version of aspenONE Process Explorer Analytics application at all.
So, to summarize, the above-mentioned fields are not needed for the current version of aspenONE Process Explorer Analytics (OEE) application.
Keywords: None
References: None |
Problem Statement: When using the Aspen Properties Excel add-in there are problems working with vertical ranges. I can use the add-in to make operations when components are arranged horizontally but not vertically. | Solution: This error can happen after a security update for Windows is applied to your system. ThisSolution applies only if you have installed the update 3006226 from the MS14-064 Security update for Windows OLE: November 11, 2014.
This security update has a known issue with array functions not working after being installed. to solve Microsoft has issued a fix. For more information about the issue and how to download the fix, go to the following link and refer to the section Known issues with this security update
https://support.microsoft.com/en-us/kb/3006226
Keywords: Aspen properties excel add-in, vertical array.
References: None |
Problem Statement: How do I link Aspen HYSYS to the Aspen Simulation Workbook? | Solution: There are two ways that you can link Aspen HYSYS to the Aspen Simulation Workbook.
Method 1
Click the Enable button . The Aspen Simulation Workbook will appear.
Click the Organizer button . The Aspen OSE Workbook Organizer will appear.
Open Aspen HYSYS and load in your case.
While in Aspen HYSYS navigate to some of the variable(s) you want to import to the Aspen Simulation workbook. For example the temperature of a stream.
Select the temperature value and select Copy command from the Edit menu.
Toggle back to the Aspen OSE Workbook Organizer. Navigate to the Model Variables page if you are not already there.
Select the Paste command from the Edit menu. You will get the message You are attempting to add variables from a simulation which has not been referenced yet. Do you want to add this simulation to the available simulation list?. Click Yes.
Your Aspen HYSYS case will be linked to the Aspen Simulation Workbook and the temperature variable will be added to the model variable list.
Method 2
Click the Enable button . The Aspen Simulation Workbook will appear.
Click the down arrow on the Active Simulation drop-down list and click <Edit List...> . The Simulation
Keywords: HYSYS, link, connect, Excel
References: s view appears.
Click the Browse button. The MS Windows Open window appears.
Navigate to the location of you Aspen HYSYS file and click Open. The name of your case will appear in the Simulation list. Click OK.
To activate the simulation click the Activate Simulation icon .
Note Aspen HYSYS will be hidden when initially open. If you want to show the simulation in the Taskbar you need to click the Show/Hide Simulation icon .
Your Aspen HYSYS simulation is now linked to the Aspen Simulation Workbook.
Note:
You can copy and paste more than one variable at a time.
You can also select variables using the variable navigator.
You can have more than one simulation linked to the Aspen Simulation Workbook at one time. However, you can only have one simulation Active at a time. |
Problem Statement: How to resolve the issue of Adaptive modeling case reports not being displayed? Sometimes, Adaptive modeling case reports are not fully displayed in any other system but in the Aspen Watch box. | Solution: This issue is solved by adding PCWS site to the Local intranet zone, or enabling compatibility view in IE.
The URL in IE determines the zone the site is running in. We normally recommend to add the PCWS site to the Local Intranet zone on the web client. Compatibility view normally sets the option to display local intranet sites in compatibility view.
Keywords: Adaptive modeling, model identification cases, model quality cases, IE, compatibility view, local intranet zone
References: None |
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