[Aidan, Radhika, Nina]
We noticed that the DC channel readout (FM30) of the JPL A1 photodiode is drifting around. What we observe with no light on the photodiode, is the DC output drifiting around. It gets particularly bad when we apply voltage to other DAC channels.
For example, the attached plot shows the DC voltage from the photodiode as I change the set voltage to the laser diode driver. To be absolutely clear, the laser driver itself was completely powered off. I'm just varying the voltage going into the set point BNC connector on the back of it.
For reference, the set up is:
DAC (300mV bias) > relay > PD > relay > FEMTO preamp (1000x gain) > ADC channel FM30