I have a wierd observation. The following two combination work:
- North PMC locked through South PMC Servo Card and then the frequency locked through North FSS Box.
- South PMC locked through North PMC Servo Card and then the frequency locked through South FSS Box.
But when I connect the South PMC to its own South PMC Servo Card, the PZT output voltage does not change with changes made to Ramp. The other side, works.
I checked the capacitance of the South PMC PZT and it came to about 395 nF which is same as specifications with the error bars. So the PZT isn't bad.
But if I disconnect the South PMC PZT from the South PMC Servo Card, the output voltage at the servo card changes as expected with ramp voltage.
This is very perplexing. I think I need second opinion here to do sanity checks otherwise I'll go mad in the basement.
Updated schematics for reference: South PMC Servo Card |