Issues description and environments
-----------------------------------

The [OpenOPC](http://openopc.sourceforge.net/) library is friendly and easy to use, the [api](http://openopc.sourceforge.net/api.html) is simple too, but I have found two issues during the development of a tool to record real time OPC items data. 

1. The development environment is: Window 8.1, Python 2.7.6, wxpython 2.8 unicode
2. The testing environment is: Window XP SP3, Python 2.7.6, wxpython 2.8 unicode, Rockwell's soft logix as OPC Server
![Test environment snapshot0](https://i.stack.imgur.com/W9sV0.jpg)
![Test environment snapshot1](https://i.stack.imgur.com/dTRXM.jpg)
3. The deploy environment is: Window XP SP3, connected with Rockwell's real PLC, installed RSLogix 5000 and RSLinx Classic Gateway

Questions
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1. the opc.list function doesn't list all the item of specify node both in testing and workstaion environment. The question is how to list the 't' from the opc server?
	* An int array 'dint100' and a dint 't' is added with RS logix 5000 at the scope of soft\_1
	![Add dint tag 't' with RS logix 5000](https://i.stack.imgur.com/RO0Mc.jpg)
	* With the default OPC client test tool from Rockwell it could list the new added 't'
	![Rockwell's default opc test tool could display 't'](https://i.stack.imgur.com/Wg5UY.jpg)
	* With OpenOPC library, I couldn't find out how to list the item 't', but I could read it's value by opc.read('[soft\_1]t') with it's tag.
	![Try to list tag 't' with OpenOPC with pythonwin but failed](https://i.stack.imgur.com/TOJza.jpg)
	* If the 't' could be listed, it could be added into the IO tree of my tool. 
	![Personal opc monitor tool snapshot](https://i.stack.imgur.com/3AZKY.jpg)
2. The opc.servers function will encounter an OPCError on the deploy environment, but the client could connect the 'RSLinx OPC Server' directly with the server name. Does opc.servers function dependent on some special dll or service? 
![opc.servers function failed on deploy environments](https://i.stack.imgur.com/3s6GT.png)

Any suggestions will be appreciated! Thanks in advance!