ryan.short@LIGO.ORG - posted 09:25, Friday 14 February 2025 - last comment - 09:35, Friday 14 February 2025(82802)
H1 Back to Observing
H1 back to observing at 16:47 UTC following a small-ish ETM glitch lockloss at 14:47 UTC. Fully automatic relock with an initial alignment.
After some time at NLN, I noticed the DCPD sums growing and traced it to ETMY violin mode 20 ringing up. Turning off the gain (nominally -1.0) stopped it from rising. After 15 minutes or so, I tried just a sign flip for the gain (so, 1.0) and so far that seems to be damping the mode down. Will keep an eye on this today. [OpsInfo]
Also had to accept SDF diffs for alsey. Corey had accepted these in reverse last night (alog82798), but trending the swstat for these filters, FM9 (a -14dB filter) is nominally OFF, hence my acceptance. Looks like it was turned on towards the end of an initial alignment, but not sure yet why.