corey.gray@LIGO.ORG - posted 21:55, Wednesday 13 November 2024 - last comment - 22:02, Wednesday 13 November 2024(81273)
H1 Lockloss at 2100utc (9pm PT) After 5hr Lock.....Now What....Leaning To IMC-only Overnight.....
The plan for tonight's shift was to see how locking would go for H1. Well....TJ handed over a locked H1, and then it stayed locked for 5hrs of the 6hr Eve shift!
- So did not determine if locking is "tough" since it was locked most of the shift
- First action was to see if H1 would relock on its own. Made it to DRMI, but flashes were ugly, so ran CHECK MICH FRINGES, but there was a lockloss during CHECK MICH FRINGES (at 5:22:27utc).
- Then it was iffy on what to do next. Would love to run an alignment, to see how H1 would look overnight for locking, but it's minutes from the end of the shift.
- SO---will opt for: IMC-ONLY Lock Overnight
- ISC_LOCK taken to IDLE at 05:40:49 <----This would be the time for the start of the "clean" period for checking Overnight IMC/FSS/PSL glitches (if any)
- IMC_LOCK at LOCKED state and taken to AUTO state (from MANAGED).
- At 0558 took OBSERVATORY MODE to CORRECTIVE MAINTENANCE
Vicky mentioned that the Lockloss at 0459utc looked like possible FSS glitch, but it looked "different". She is going to post her plot about that.
This lockloss (1415595557, 2024-11-13 20:58:59 PT) looks related to IMC (/FSS /ISS / PSL)... 10-15 seconds before LL, FSS starts to see some glitches, then more glitches starting ~5 sec before LL. ~30 second trends here.
Then zooming in ~100ms before LL (plot), maybe a small glitch is seen on ISS second loop PDs, and then the IMC loses lock. At the same time that the IMC loses lock, then lockloss pulse and AS port and LSC_REFL see the lock loss. So it seems like an IMC lockloss with some FSS glitching beforehand.