TITLE: 12/29 Eve Shift: 0030-0600 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 158Mpc
INCOMING OPERATOR: Ryan C
SHIFT SUMMARY: Currently Observing and have been Locked for almost 2 hours. Just spent an hour working with Vicky to get sqz back up and running because it had unlocked and I couldn't get it to relock. SQZ_LO guardian had the message "Beam diverter is open but no 3MHz on OMC, could be an alignment problem".
With Vicky, we first tried resetting the SQZ angle by manualing to the RESEST_SQZ_ASC_FDS guardian state in SQZ_Manager, but that didn't work. The problem was that the FC couldn't even lock because the LO couldn't lock. What had happened is that the "squeezer angle servo ran away, and because squeezer ASC alignment setpoints are coupled to the SQZ angle, so this time when SQZ ANGLE runs away it also drags the SQZ ASC away. This time it dragged the SQZ ASC away enough that the LO loop could not lock (because nearly no signal on SQZ-OMC_RF3 beatnote (RF3 was around -22, normally around -9)" (Vicky, 2024).
What we did that ended up working (and the ideal way to do this in the future):
- Reset SQZ angle (CLF_REFL_RF6 to 185)
- Go to NO_SQZ
- Trend ZM4 and ZM6 driftmon and adjust sliders to bring SUS back to last time in FDS (last lock)
- Go back to FDS
Vicky's notes on sqz todo's regarding this problem:
- "Improve the notification given (currently "Beam diverter is open but no 3MHz on OMC, could be an alignment problem") when SQZ_LO can't lock to alert ops to check SQZ ASC or check ZM4/6 LOCK filters, etc, to make this problem more diagnosable"
- "SQZ MANAGER needs a more robust way to clear SQZ ASC now that integrators are in the ZM4/6 LOCK filter banks (see https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=80534). Oli tried to RESET_SQZ_ASC_FDS but that didn't clear the suspension lock filter banks."
- "We should get at more robust guardian state to clear SQZ ASC in the lock filter integerators, and corresponding OPS instructions for when OMC RF3 LO locking fails + SQZ ANGLE is railed (I found it at 235 ish, it should be like 185-195). "
* All quotes by Vicky
On a different note, I figured out why the LOCKLOSS_SHUTTER_CHECK guardian had been stuck stalled and had been requiring us to change the states between high and low arm power - it's because it is NOT normally managed by ISC_LOCK like I had thought. Yesterday after I had MANUAL'd it, thinking that it had previously been managed by ISC_LOCK, I set it to be managed by ISC_LOCK. It actually is normally just on AUTO. I set it to AUTO and had no issues with it during the locking sequence.
LOG:
00:05 Started trying to relock
- Sitting in OMC_WHITENING for an hour damping violins
02:45 NOMINAL_LOW_NOISE
02:45 Observing
03:51 Lockloss https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=82037
05:23 NOMINAL_LOW_NOISE
05:25 Observing
05:46 Out of Observing due to squeezer unlock
- SQZ_LO gives message "Beam diverter is open but no 3MHz on OMC, could be an alignment problem"
- With help from Vicky, we figured it out
07:02 Back to Observing
| Start Time | System | Name | Location | Lazer_Haz | Task | Time End |
|---|---|---|---|---|---|---|
| 21:29 | Corey | LVEA, FCES | n | Walkthrough | 21:55 | |
| 21:55 | Corey | EY, EX | n | Walkthrough pt 2 | 22:41 |