I tried to implement the ISS servo today for the east path with little to no success
It it not clear to me that the servo was engineered with the actual driver in mind
The AOM driver is only linear over a narrow input range: [156mV to 450 mV] (can be + or -)
The ISS board seems to go to not have this offset built in, and it is not clear if the excitation inputs would be an appropriate place to add this.
I played around with using terminators on the input and output signals to try to force the DC value at the output of the ISS board to the middle of the linear range, but could not get the loop to do any actual intensity noise suppression for any switching state on the front
I punt to Nic, interim king of ISS servo board, following the passing of Prince Chaz, rightful heir to the throne, to determine what the correct way to sum an offset into the output of the board is.