I centetered PRM oplev, lowered gain and PRM oplev servo is not oscillating any more.
It is OK for more than a softball practice.
C1:SUS-PRM_OLPIT_GAIN = 0.15 (was 0.5)
C1:SUS-PRM_OLYAW_GAIN = -0.3 (was 0.7)
Openloop transfer function:
Oplev Pitch: gain ~ 12 at 0.69 Hz resonance
Oplev Yaw: gain ~ 18 at 0.83 Hz resonance
I adjusted the gain so that oplev damps resonance as much as possible, but not introduce additional noise. I did no calculation, but just measured OSEM spectra (SUSPIT and SUSYAW). Below, you can see the noise reduces at resonance when oplev servo is on, and not increasing at other frequencies. It was introducing noise before. Someone should do more systematic adjustment of oplev servos for all the optics.