MZ work has been done. I did not change anything on the circuit.
Recently we observed that the MZ PZT output was sticking at a certain voltage. I found the reason.
Shortly to say "we must return the PZT Ramp offset to 0, after the lock"
I am going to write a MZ auto lock script someday, to do it automatically.
According to the resister values used in the circuit, the PZT HV output voltage is determined by the following formula:
V_PZT = 150 - 12 V_ctrl - 24 Vramp
Here the ramp voltage Vramp moves from -10V to +10V, the feedback control voltage V_ctrl moves from -13V to +13V.
The baseline offset of 150V is provided in the circuit board.
When V_ramp is 0, V_PZT runs from 0 to 300. This is just enough for the full scale of the actual V_PZT range,
that is 0V~280V.
If any Vramp offset is given, V_PZT rails at either side of the edges. This limits the actual range of the PZT out.
This is not nice, but is what happened recently.
I will investigate the MZ board. I will unlock MZ (and MC).