Below a teardown of the thermometry readout built like a tank equipment.
I had no luck with finding A1012 manual or schematics, but found out that Omega DP95 is a re-branded Azonix A1011.
Fortunately DP95 manual is compatible with A1012 with some minor differences. The same with GPIB commands.
The readout provides four galvanically isolated independent channels measuring in 0...320 ohms in 4 wire connection.
Excitation current is approx. 2mA. No offset compensation.
Advanced configuration can be performed via GPIB or attachable front panel (which I don't have, but I learned how to skip that).
This front panel uses small magnet to trigger the Hall effect sensor to enter configuration mode.
In my case this Hall sensor occurred to fail (!). Fortunately it has open collector output so I temporarily use parallel switch.
My unit has 3rd channel modified by the manufacturer.
If someone has any more info on these or similar readouts please post or PM me.








