Hello all,
Disclaimer: I am relatively new to LabVIEW so it's very possible that there's something easy and obvious that I am missing. That said, I thank you in advance for your help.
I am writing a data acquisition program for an experimental setup featuring multiple instruments from which I need to record data asynchronously over a GPIB connection.
My plan, I thought, was pretty straightforward: I wish to use the GPIB I/O functions to wait for an instrument to interrupt the controller, serial poll to find out which instrument has data ready, read, then repeat.
For the moment, I am testing my program with an HP 3478A DMM.
My problem is this: I noticed using NI I/O Trace that my program gets hung up for more than ten seconds whenever it needs to read an instrument output. However, I know I have read from this instrument at far greater speeds. I built a quick test VI, and noticed that if I simply read from the instrument without checking for SRQ or Data Ready then GPIB Read operates quickly (0.2 s/measurement). However, if I insert an SPOLL before the Read (not doing anything with it, just calling the function) then it hangs for around 17 seconds before continuing.
I have attached my simple test VI, an image of it, as well as screen-shots of the I/O Trace outputs for when the SPOLL is enabled vs disabled.
Again, I am pretty new to LabVIEW; it may be that this is some simple error, or that it's something specific to the 3478A, or our GPIB set up.
Thank you again for your help!
