ace="Arial">Back to the form</font></a> </p></body></html> 10000000000000000000000000000000000000000000 Figure 12.13 VI diagram frame that assembles the results.html file by simple string concatenation. Service Delivery Platforms The experimental configuration controlled by the "workbench server" PC run- ning MS Windows is built around National Instruments (NI) AT MIO 16E10 or PCI6024E analog and digital signals acquisition and generation board, integrated with NI "LabVIEW" in a virtual instrumentation (VI) system with Internet (including WAP) access. For remote-controlled switching (in order to redirect signals, to reconfigure the subsystems and to adjust the loads), it was accomplished with relays block, con- trolled (by LabVIEW) via the parallel port (that has the specific advantage of being "latched," keeping this way stable configurations). These DAQ&D cards given as example have an excellent resolution of 12 bits/ sample and peak outputs of +10 V (then, the LSB corresponds with 10 V/ (212) = 0.00244140625 V which is appropriate also for small-signal studies). At client level, stimuli are posted with a mouse click on the "Submit" button in experiment's control page (e.g., http://vlab.unitbv.ro/VELab/bjt/bjt.stimuli.php), arriving at Web server into a .TXT file associated to the Web form (e.g., .stimuli. txt for the above particular case of Bipolar Junction Transistor, BJT). The VI runs, in "Continuous" mode, a wait-loop (based on the measurement of input.txt file's length-equal to zero if no new forms were posted from remote; the file input.txt is purged after reading). If stimuli were posted, the step-out from the loop contin- ues with a frame where they are extracted out from the labels (e.g., U1_start: U1_ stop: etc.,-by LabVIEW string processing) and directed to the two analog outputs (AO) of DAQ&D card (in this case, for U1 and U2 that supply the base and collec- tor's circuit respectively) in steps that are internally computed (e.g., (U1_stop-U1_ start)/U1_steps#) for multipoint, automated, measurement