aLIGO LHO Logbook

H1 AOS

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corey.gray@LIGO.ORG - posted 06:49, Saturday 04 May 2019 - last comment - 10:41, Saturday 04 May 2019(48975)

H1 Lockloss: ALSy Issues

Symptoms:

Do not see a spot for ALSy on the video
Error signal for CAM ITM PIT is above 0.2 (it is at -1.2). Trouble shooting document said I should Clear History, but that does not appear to work any more (the file for it is no longer in the folder....so maybe this is an old solution?)
- Clear History file was: /opt/rtcds/userapps/release/asc/h1/scripts/softCH_arm.py (but softCH_arm.py is no longer in that folder)
Continue investigating

Comments related to this report

corey.gray@LIGO.ORG - 07:08, Saturday 04 May 2019 (48976)

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I forgot about Jenne's note about changing AS_A_36 phase. So I have done that, but it didn't address the ALSy issue.

Trending oplevs for ETMy & ITMy does show some big alignment changes. I still wonder if this is related to a WFS issue. Will steer optics back to see what this does.

NOTE: I have not seen this issue before with a Y-arm misalignment like this!

corey.gray@LIGO.ORG - 08:25, Saturday 04 May 2019 (48977)

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Ed's here to save the day, but I'm trying to remember what I saw & did with ALSy.

Definitely saw ITMy & ETMy both shift their alignment! (see attached to see ITMy/ETMy pit/yaw shifts & various things I did to bring back).

Back Story:

Lockloss after 42-hr lock.
For relocking, immediately saw Green Y was in la la land
- No light on ALSy video! AND ALS-C_TRY_A_LF_OUT was dead flat at zero! So there was no flashing in the arm!
- Issues on ALS Y Overview
  - Green WFS spots were visibly off
  - CAM ITM PIT Error signal was way above -0.2 (it was -1.2!). On Jenne's old trouble-shooting document, it send to hit to hit Clear History button on the ALS Y Overview screen (but this button no longer seems to work....the clear history command/script/file is no longer in there)
- Trended ETMy & ITMy and they shifted alot after the lockloss!
  - Because of ALS Y Overview issues due to WFS noted above, I was worried the issue was there, but since I couldn't fix anything with that, I started with moving optics.
- Moved ETMy & ITMy back to pointing during the lock. This finally gave baby flashes for ALS TRY.
  - Oh! Around this point is where I remembered to run the command Jenne alogged about on Thurs!
- Walked ETMy, ITMy, & TMSy (by alot!) over several iterations. Eventually had flashes over 1.0.
- Locked up ALS-Y (and finally gave ALSx attention).
- Tried locking, but "IR was not found"
  - Ed came in and he found IR, but PRMI flashes looked UGLY! He is now running an INITIAL ALIGNMENT.

Images attached to this comment

corey.gray@LIGO.ORG - 10:41, Saturday 04 May 2019 (48980)

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Wanted to also mention that I clicked on the "Clear History" for each of the individual Filter Banks on the ALS Y Overview (which I assume the non-functioning yellow Clear History button would do on this medm window). When I did this I did not notice any change to the CAM ITM PIT Error signal. These filter banks had their inputs OFF and their outputs were zero. Just wanted to note that I did click their Clear Histories though.