Instrument Control (GPIB, Serial, VISA, IVI)
BK Precision 5491B multimeter control
I'm working on a program that communicates with a BK 5491b multimeter. I have a program written thats able to send *IDN? to the meter and then read the response to validate the serial number. The problem is it only works about half the time. I have used NI IO Trace to check the VISA calls being made and all traces from the success cases match the calls from the failure cases except for the read that times out. I have tried increasing the timeout to no avail. I have tried with several different computer/meter/cable setups as well. I have tried other versions of the COM drivers that the meter uses. I've tried clearing and flushing buffers and making sure i close resources properly. The program will eventually communicate with 2 meters simultaneously and sometimes it can find one meter and not the other or none at all. Im at a bit of a loss. The interesting thing is I have another program that just communicates over serial without the VISA and its able to work 100% of the time without fail.
