Hi there,
I came across a new phenomenon, I never see in before but you migth. Any comments or suggestions are welcomed as I don't really know how to tackle this one. Here the details.
I am running Labview 7.1 in an XP computer that connects to two instruments via the NI USB-GPIB-HS. The two instruments are 1) an Agilent function generator and 2) a Coherent power supply (EPM2000). Both instruments have their manufacturer provided labview drivers which I have used in the past on other code without problems.
Now, in a few words here is how the VI should go: At the beggining initialize both instruments. Then enter a loop that queries the power meter and display/store the values. The loop is timed so that one power measurement is queried every second. When the user presses a button the loop stops and both instruments remote mode are released.
Well it seems to work fine instrument initialization works perfectly, then in the loop the first 5 measurements happen as expected (every second) but after the 5 measurement every query to the power meter will take about 18 s. Tracking it down with the debugger seems that is the the "GPIB write" VI that stalls for that long.
Here is what I tried.
- A different power meter... same problem
- A different computer but running same software and windows XP.... same problem
- Change the power meter drivers and use the Instrument assistant for quering the instrument.... same problem
- Isolate the Instrument assistant vi in a new vi template, run it and runs properly (in this test, there was no inizialization/setting to the instrument)
- Tried the same test vi with the query driver and worked properly.
- Copy the test vi in the original code and starts giving me the same problem.
Any ideas? -- I want to think that something in the vi settings but I am clueless.... Thank you for your time!
