When the gain of the ISS second loop was changed, the input offset was not adjusted. This results in the output of the 2nd loop ISS to saturate after a lock loss, until the offset slowly gets compensated by the offset loop. But, this now typically takes like 5 minutes. I adjusted the offset (H1:PSL-ISS_THIRDLOOP_OUTPUT_OFFSET) from 587.3 to 1272. We will have to check after the next lock loss that this actually works.
Just had a lock loss. Looks a lot better now.
I disabled the diffraction servo by setting H1:PSL-ISS_SECONDLOOP_REFERENCE_IN_MTRX_1_4 to 0 (from 10). This should stabilize the power after the IMC, rather than keep the pwer at the PSL AOM constant. The downside is that we may run out of range of the AOM, since we only work at 2% diffraction power.
Tagging PSL.
The diffraction servo value that Daniel has made 0 from 10 had been hard-coded into the DOWN state of the IMC_LOCK guardian, so was getting overwritten.
RyanS and I just set the value in the guardian to zero, loaded, and checked it in to the svn.
First hour trend during a lock with the diffraction compensation off: The powers are no longer drifting a significant amount after the mode cleaner.
