3421A CAL RAM

[Dave Frederickson]

In the Feb 83 issue of the HP Journal in the article on the 3421A, under Advanced Instruction Set on p.15 it lists:

CAL Calibration RAM (1 if read, 2 if write)

It also states:
The calibration constants can also be read or written to by an HP-IL controller through the instrument's I/O interface.

This could be interesting, but this is the only reference to this command I can find.

If the method for doing so can be determined then it might be possible to clear a CAL RAM error without a costly calibration service. The best I've been able to figure out is that issuing the CAL write with the CAL Enable switch off generates an error. With the switch on no error occurs. Any attempt to read data just gives the reading from the front terminals.

It does say "by an HP-IL controller" so maybe it requires low-level commands. Anybody know how to do this?

Dave