Koji asked me to get the calibration of the PZT counts to Volts for the the X and Y ends. Yesterday, I went inside the lab and took some measurements from the digital readout of the PZT by giving in a DC offset(-5 to +5 volts) to PZT_Out and read out from these channels:
For X-end: C1:ALS-X-SLOW_SERVO1_IN1
For Y-end: C1:ALS-Y-SLOW_SERVO1_IN1
Since a 20dB attenuator was placed in the path of X-arm readout while taking the Transfer functions(Detail), I did the calibration measurements without removing it from the path. However, for the Y arm there was no attenuator in the readout path.
The obtained calibration values are :
X- arm PZT : [146.3 +/- 2.37 ] counts/Volt
Y- arm PZT : [ 755.1 +/- 3.6] counts/Volt
The attached are the fit and data plots for the above calibration.