Sheila, Francisco, Louis
We would like to measure the sensing function when the IFO is thermalized, with different DHARD ASC loop gains, to see if we still have the ASC cross coupling impacting the sensing function as we saw back in O3: 50511
Based on the measurement in 77857 we thought we could increase the gain of DHARD P from -30 to -45. This worked fine, so we also tried increasing the gain of DHARD Y from -40 to -60, we were also stable with both of these gains increased by 50%. I then increased DHARD Y further stepping up to -80 where we lost lock.