In the past days I was running some long measurements sequences, and noticed that the measuring times were lower than expected.
Long story short: The integration times were corresponding to a device running on a 60 Hz power line while the power line, here in France, is 50 Hz (except any very recent changes
).
After investigation and some luck, I discovered that if you do a manual reset from the front panel, the DMM is set for a 60Hz power line frequency and all integration times are affected accordingly.
This can be checked with the SYSTEM:LFR? SCPI command which is
not documented both in the French or English manuals.
There are 2 ways to set back the DMM in the correct LF state after a front panel manual reset:
1) Power OFF, power ON ...
2) Send to the DMM the SCPI command: SYSTEM:LFR 50
The SYSTEM:PRESET command which is, according the French and English manuals, supposed to produce the same result than a front panel Reset, don't.
While a front panel Reset set the LF to 60Hz, the SYSTEM:PRESET command do not affect it.
I don't know how this bug affects the measurements, but for sure, this need to be fixed.
I would appreciate to have a feedback from other 34460A, 34461A, 34465A, 34470A user's.
My 34461A is running with the latest firmware rev.
Thanks for your feedback.
Jean