I realize this is a smallish use case, but I am posting here for future interweb queriers.
I have several functional, yet discontinued, HP8970B Noise Figure Meters that preset whenever NI-MAX performs a 'scan for instruments' or when I attempt a 'communicate with instrument' on them. Using IO Trace, I found the culprit is 'ibclr'.
Given this instrument predates SCPI, it does not understand '*idn?', and will reply with an error code. That is fine, but presetting is not. This clears my calibration and other settings. 😞
