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Entry  Tue May 24 11:04:53 2022, JC, Update, VAC, Beginning Pumpdown PUMPDOWN-2022-05-24_16-57-59.pngC1VAC_Screenshot_2022-05-24_16-59-27.png
    Reply  Wed May 25 16:38:27 2022, yuta, Update, SUS, Suspensions quick health check Screenshot_2022-05-25_16-46-13.pngOSEMcheck.JPG
       Reply  Tue Jun 7 17:26:21 2022, yuta, Update, SUS, ITMY ULCOIL mystery not solved ULCoilInductance.JPGULCoilResistance.JPGWrongSetting.JPG
          Reply  Tue Jun 7 19:13:12 2022, yuta, Update, SUS, Agreement on suspension damping loop polarity conventions NoteBeforeChanges.JPG
             Reply  Fri Jun 10 15:02:04 2022, yuta, Update, SUS, Servo gain sign flipped for MC1 WFS relief Screenshot_2022-06-10_15-04-46.png
          Reply  Tue Jun 7 19:40:45 2022, Anchal, Update, SUS, ITMY changed output matrix to disable use of UL coil ITMY_PIT_to_POS-PIT-YAW_Coupling.pdfITMY_YAW_to_POS-PIT-YAW_Coupling.pdf
          Reply  Wed Jun 8 18:16:20 2022, yuta, Update, SUS, ITMY ULCOIL mystery: Coil driver swap test Screenshot_2022-06-08_18-10-44.pngSWAP.JPG
             Reply  Thu Jun 9 23:08:39 2022, rana, Update, SUS, ITMY ULCOIL mystery: Coil driver swap test 
                Reply  Fri Jun 10 13:02:14 2022, yuta, Update, SUS, ITMY ULCOIL mystery: Coil driver swap test 
                   Reply  Fri Jun 10 15:04:23 2022, rana, Update, SUS, ITMY ULCOIL mystery: Coil driver swap test 
                      Reply  Fri Jun 10 21:10:01 2022, yuta, Update, SUS, ITMY ULCOIL mystery: Coil driver swap test 
                         Reply  Wed Jun 15 17:03:17 2022, yuta, Update, SUS, ITMY ULCOIL issue solved, loose connection in sat amp box Measured16Ohms.JPGSatAmpTerminator.JPGBAD.JPGSUCCESSFUL_KICK.png
       Reply  Wed Jun 15 15:45:37 2022, yuta, Update, SUS, LO1 LLCOIL now working, it was loose connection Measurement.JPGBAD.JPGScreenshot_2022-06-15_15-59-05.png
    Reply  Wed Jun 15 07:26:35 2022, JC, Update, VAC, Beginning Pumpdown 
Message ID: 16920     Entry time: Wed Jun 15 17:03:17 2022     In reply to: 16910
Author: yuta 
Type: Update 
Category: SUS 
Subject: ITMY ULCOIL issue solved, loose connection in sat amp box 

[Anchal, Yuta]

We fixed the issue of ITMY ULCOIL not driving ITMY by replacing one of the 64pin ribbon cable in the satellite amplifier box.
We thought the coil driver and the sat amp box are OK by checking the voltage change at the output of the sat amp box by giving an offset to UL coil driver, but it was not giving a current change, probably due to too much contact resistance in the cables.
It was sneaky because it was not completely disconnected.

All the coils for our suspensions are now working!

What we did:
 - Using breakout boards, the output current of sat amp box was measured using FLUKE multimeter. It turned out that UL is not giving measurable current. We also confirmed that UR coil driver can drive UL by re-directing the current from UR coil driver to UL. This means that the UL magnet was not de-magnetized!
 - Measured the coil resistance from at the coil driver output and found that UL coil seen from there has too high resistance which cannot be measured with the multimeter, whereas UR coil was measured to be ~30 Ohms.
 - Went back to the feedthru and measured the resistance of UL coil. Upto the output of the Satellite Amp Terimator, the resistance was measured to be ~16 Ohms, but not at the input of the Satellite Amp Terimator (Attachment #1,2).
 - It turned out that #16 pin of 64pin ribbon cable in between the Satellite Amp Terimator (LIGO-D990021) and the Satellite Amp board (LIGO-D961289) at the Satellite Amp Terimator side was not good (Attachment #3).
 - Replaced the cable and confirmed that ULCOIL can kick ITMY (Attachment #4).
 - C1:SUS-ITMY_TO_COIL matrix was reverted to default values.

Next:
 - We might have to re-commission Yarm ASS again since pitch-yaw coupling have changed. -> EDIT: Checked that it works (except for ITM PIT L), including offloading offsets (writeASS_offsets.py), 18:30 local.
 - Now that LO1 LLCOIL issue is solved and LO2 stuck is solved, we should do the free swing test again to identify the resonant frequencies.
 - OSEM sensor diagonalization (input matrix), coil balancing (and F2A)

Attachment 1: Measured16Ohms.JPG  3.766 MB  Uploaded Wed Jun 15 18:39:53 2022  | Show | Hide all | Show all
Attachment 2: SatAmpTerminator.JPG  3.854 MB  Uploaded Wed Jun 15 18:40:03 2022  | Hide | Hide all | Show all
SatAmpTerminator.JPG
Attachment 3: BAD.JPG  3.389 MB  Uploaded Wed Jun 15 18:40:13 2022  | Hide | Hide all | Show all
BAD.JPG
Attachment 4: SUCCESSFUL_KICK.png  31 kB  Uploaded Wed Jun 15 18:40:54 2022  | Hide | Hide all | Show all
SUCCESSFUL_KICK.png
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