FAQs from Rohde & Schwarz

RTB/RTM/RTA – Measurement result implausible after channel switching

Description

I do RMS measurement on a signal after switching the channels. Even with *OPC? or *WAI the result is implausible: 9.91e+37

How can I get a correct result?

Resolution

Also at measurements it is necessary to do a single acquisition and wait until it has been finished. Only then you get plausible results. Here is an example SCPI sequence with channel switching:

CHAN1:AOFF
CHAN2:STAT ON
MEAS1:SOUR CH2
STOP --> stops the acquistion
SING --> starts a single acquisition
*OPC? --> after “1” is returned you can continue and query the measurement result:
MEAS1:RES? RMS