Some measurements. Unclear meaning.
We tried both positive and negative numbers in the CARM offset, and then looked at transfer functions at various arm powers. The hope is to be able to compare these with some simulation to figure out which side of the CARM resonance we are on.
The biggest empirical take-away is that we repeatedly (3 times in a row) lost lock when holding at arm powers of about 5 with negative CARM offsets. However, we were repeatedly (2+ times tonight) able to sit and hold at arm powers of 10+ with positive CARM offsets.
I am not sure that we get enough information out of these plots to tell us which side of the CARM resonance we are really on. Q is working on taking some open loop CARM measurements (actuating and measuring at SUS-MC2_LSC) to see if we can compare those more directly to Rana's plots.
Positive number in the digital CARM offset:
Negative numbers in digital CARM offset: