corey.gray@LIGO.ORG - posted 07:11, Friday 06 September 2019 (51772)
H1 Locking Woes, But Back After 2.5hrs
Had a rough time getting H1 back after the lockloss. With issues primarily around the ASC steps. Ran an Initial Alignment, but that didn't solve the issue since it took a few attempts after the IA was run to finally get it back to NLN.
Here is a summary of Locking notes:
- 11:29 Locklos
- Lock#1:
- X-arm driven out of alignment. (11:31-11:33) Unlocked and touched up ETMx & TMSx
- Note: Did not see any of the ALSx errors TJ & Keita noticed.
- Went directly to PRMI LOCKED: PRMI locks were low & only on order of 1-2seconds. Tried to touch up on fly (BS first in yaw...and then in pitch). After 10min PRMI locked for more than 2-seconds and I was able to touch up (mainly) the BS & PRM. Then gave ASC a chance to improve alignment a little more.
- While DRMI flashing, noticed possible pitch misalignment so adjusted SRM in pitch. DRMI locked within 2-min.
- at PREP ASC there were a few rough spots (OMC was reaching saturation levels for a few seconds), but it managed to ride through OK.
- 12:00 Lockloss at ENGAGE ASC. This was fast (in that didn't see any ASC CONTROL signals slowly grow such that I'd want to reduce error signals per #51282 so not sure what unlocked H1.)
- X-arm driven out of alignment. (11:31-11:33) Unlocked and touched up ETMx & TMSx
- Lock#2 (12:01-12:17):
- Taking to ENGAGE ASC.
- Identical lockloss at ENGAGE_ASC
- Lock#3 (12:17-13:14)
- Initial Alignment (12:19-12:33, with no issues for any states...I failed to switch Observatory Mode to Alignment, and only caught the last portion of the IA)
- NOTE: SUS OM1 WD trip during PRC aligning which was odd & new to me.
- DRMI did not lock in 10min. PRMI locked in about 4min
- Lockloss PRMI ASC
- Initial Alignment (12:19-12:33, with no issues for any states...I failed to switch Observatory Mode to Alignment, and only caught the last portion of the IA)
- Lock#4
- Couldn't FIND IR, so I ran DOWN
- Lock #5 (13:06-13:27)
- Finally made it past ENGAGE ASC
- Received saturations for SUS-OMC which also correlated saturations with the L2 stages of both ITMs & ETMs...this was coincident with a big ring up in DHARD_P....but then all of this calmed down on its own with no action by me.
- Lockloss at DARM TO DC READOUT....looks like possibly SRC2_P (& to a smaller extent SRC2_Y) was getting rung up.
- Lock #6 (13:28-14:07)
- Spent a few minutes in the ASC states , but other than that went directly to NLN & then Observing (w/ no SDF diffs to deal with)
- 14:07 Back to Observing