Tonight PRMI was locked on REFL55 I&Q for PRCL and MICH with POP110I as a trigger and power normalizer.
I could see power fluctuations and beam motion on the POP camera very much the same as for carrier. The difference is that carrier stays for hours while sidebands for a few minutes.
I&Q analog gains were set to 15 dB. Relative phase was set to 25 degrees by looking at I and Q components when the cavity goes through the resonance. Q should be 0.
Phase rotation was measured by exciting PRM at 20 Hz and minimizing this line at REFL55_Q. I stopped at 33 degrees.
I compared power fluctuations of PRCL when it was locked on carrier (POP_DC) and on sidebands (POP110_I).
Time series of POP110_I during one of the locks