No more HP3478A dead battery anxiety!
Thanks to some info that I found on this board, I've now added an option to backup and restore the meter calibration data. You no longer need to worry about losing the meter calibration data because of a dead battery!
This is a Windows program. It requires a Prologix (or compatible) GPIB adapter.
Even if you don't need to log data or control the meter using your computer, you may want to use this program just to back up your calibration data.
My program performs a checksum on the cal data when performing a read or write. Also, a write verify.
I decided that I couldn't publish this software without a thorough test. I risked wiping my meter cal to verifiy that the program can properly read and write the cal data.
I turned on the cal enable switch to fully test the code. I edited the saved cal file to create bad checksums and then wrote it back to the meter. I then verified that the meter showed a calibration fail. Next, I wrote the good cal file back to the meter. The meter was now showing good calibration.
Even with this testing, I would suggest that you should not try to write your meter's calibration unless it's really necessary.
Also, You can do a safe (but not complete) test by doing a read and then a write with the cal switch disabled. The cal switch is a hardware write protect. Software can't override it. If the read and write match, the program will report no errors.
If there are no errors, the software and GPIB interface are working properly.
Finally, if you use an NI VISA USB to GPIB adapter there is backup software available in this thread.
https://www.eevblog.com/forum/repair/hp-3478a-how-to-readwrite-cal-sram/msg1177575/#msg1177575That's where I found the info needed to port this into my code.