Chris Whittle, Jenne, Jeff K

Wanted to test methods of measuring ITM charge.  We didn't have DARM to check, but the code for length drive charge measurements seems to work. This code (/ligo/svncommon/SusSVN/sus/trunk/QUAD/Common/Scripts/ESD_ITM_charge_measurement.py) measures the DARM response at various bias voltages and finds the TM charge as the zero crossing.

We tried driving the ITMY ESD to see if we could do the same optical lever charge measurements as the ETM. We tried turning off UL and LL to get a yaw drive. Changing the voltage bias on the test mass resulted in no change in phase in the optical lever (as would have been expected). We also tried a pitch drive and single quadrant drive and saw the same lack of phase change. We need to confirm the mappings for the ESD quadrant switches. The SUS overview screen was inconsistent with the binary I/O screen. We also need to make sure that the analog switches are actually switching.