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H1 General

corey.gray@LIGO.ORG - posted 10:45, Wednesday 12 June 2019 - last comment - 12:28, Wednesday 12 June 2019(49849)

Operator Locking Notes After Beckhoff Crash

Attempt #1:

These are notes from first locking attempt (thought I'd give it a go before trying an alignment).

16:44: Locking Both arms were misaligned in green, requiring UNLOCKED tweaks (more on y than x).
Was watching the ALS_[X/Y]ARM nodes, and thought they were operating differently, but I think it's mainly that the ALS Arm Guardian nodes look slightly different. ALS_YARM has it's OFFLOAD_ETM_TMS_WFS highlighted in dark blue (whereas Xarm is light blue).
Went for PRMI and we looked dead (no flashes at all).
Went for CHECK_MICH_FRINGES, and could see misalignment, so moved BS to center the spot.
PRMI had signs of flashing life, but still not great, so I focused on PRM and moved it until flashes increased in magnitude. Then PRMI locked & went through usual procedure of tweaking BS & PRM.
DRMI locked within a couple of minutes, but ASC drove POP18 down and ....
17:27: LOCKLOSS (NOTE: as ASC drove POP18 down, POP90 was driven up a little).

Attempt #2:

Giving it a try on 2nd lock and going straight for ACQUIRE_DRMI_1F, and made it here with no issues. At this point, I was wary if I could tweak anything to help prevent POP18 being driven off by ASC. Decided to go for it.

Once again, ASC scarily drove POP18 down (& POP90 up), but this time ASC turned them around and we survived.

Continuing with LOCKING! (Stay Tuned!)

Comments related to this report

corey.gray@LIGO.ORG - 11:50, Wednesday 12 June 2019 (49850)

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Summary: H1 back to Observing after Beckhoff crash. No Initial Alignment needed (but arms, BS, & PRM needed tweaking). ASC still has issues in DRMI (sometimes).

(Attempt #2 [which started at 17:28utc] Continuing from DRMI...)

Did not tweak anybody for DRMI when the ASC was off at PREP_TR_CARM.
Had a notification for OMC_LOCK "missing the mode & needing to be relocked by hand" (maybe this was around PREP or ENGAGE ASC).
- Taken care of in PREP_DC_READOUT_TRANSITION
ENGAGE_SOFT_LOOPS drove POP18 & PR GAIN down a little step (but not an issue).
Selected NOMINAL_LOW_NOISE & made it all the way to NLN at 18:10...just as Sheila was walking in.
Saw a few diffs (the "usual" SUS SR3 signif figure difference, which I've been accepting), and there was one for the IMC PZTs due to change from Jim earlier in the morning. Sheila confirmed his changes were fine, and ACCEPTED this diff (screenshot of diff attached).
18:20 Back to OBSERVING (yay!)

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sheila.dwyer@LIGO.ORG - 12:28, Wednesday 12 June 2019 (49853)

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Thanks Corey for the detailed information.

I had changed around which states were requestable (show up in darker blue and in drop down menu) to be just the states that we expect to be normally in use to help clear up some confusion that arose after we added TMS WFS to the normal sequence. I had left things inconsistent between the two arms, as Corey noted, so he and I fixed that just before going to observe.

The issue with the DRMI ASC needs more work, we could think about setting an offset for the 36WFS when we are aligned using AS45, then ramping that offset off in full lock.