DRMI ASC vs Full IFO ASC
We've been having a hard time with the full IFO ASC taking us to a bad alignment and causing locklosses. After a lockloss today I tried doing a WFS relief to a previous time we were at DC readout with good alignment, but even with this alignment we lost lock at engage_asc_for_full_ifo.
I plotted the witness monitors from a time when we survived the ASC engagement, the SRM yaw alignment changes dramatically when we engage the full ASC, as does PRM and IM4 - cyan, brown, and pale yellow in the attachment. Maybe we need to revisit the AS72 phasing?
Bounce-roll mode
A couple of days ago we noted that the LOWNOISE_ASC state took a long time while we waited for the bouce-roll mode to ring down. I raised the threshold for what is "rung up" in the guardian checker, so we could get through quicker. Today we had a lockloss due to the ITMY ITMX and ETMX bounce modes ringing up, so i reverted the checker.
We found that we struggled getting through the locking when DRMI ASC had lower and noisier RF18. Spent some time finding an alignment which got us RF18~75 and that seems to get through much easier. RF18 drops a lot when engaging ASC but the PRG stays constant.
Bounce modes rung up a several times too and caused a few locklosses.