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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: 16896     Entry time: Tue Jun 7 17:26:21 2022     In reply to: 16873     Reply to this: 16898   16899   16903
Author: yuta 
Type: Update 
Category: SUS 
Subject: ITMY ULCOIL mystery not solved 

[Paco, Yuta]

We investigated the ITMY ULCOIL issue (40m/16873).
ULSEN is sensing the optic motion but ULCOIL cannot move the optic.
We confirmed that the coil input is there upto satellite amplifier output.
We also checked that ULCOIL have 3.3 mH and 16 Ohms, which are consistent with other coils.
Mystery remains...
We need to investigate ITMY ULCOIL in the next vent.

What we did:
 - Checked again that C1:SUS-ITMY_ULCOIL_OFFSET does not kick ITMY using OSEM sensor signals and oplev signals. ULSEN moves when ITMY is kicked by other coils.
 - Checked that kick gives voltage changes at coil driver and satellite amplifier output. We unplugged J1 DB25 cable from the feedthru flange and checked the signals sent to coil with oscilloscope.
 - Measured inductance (using BK PRECISION LCR meter) and resistance (using Fluke) of coils for ITMY. Below is the result. UL coil seems to be consistent with other coils. (It seems like BK PRECISION one wil give wrong resistance if the dial is set to the resistance value which is too low compared with the one you want to measure. If you want to measure 16Ω, set the dial to larger than 20Ω, not 2Ω)

Feedthru connector: ITMY1
Pin 3-15 / R = 16.3Ω / L = 3.32 mH (UL)
Pin 7-19 / R = 16.4Ω / L = 3.30 mH (UR)
Pin11-23 / R = 16.2Ω / L = 3.31 mH (LL)

Feedthru connector: ITMY2
Pin 3-15 / N/A
Pin 7-19 / R = 16.3Ω / L = 3.30 mH (SD)
Pin11-23 / R = 16.4Ω / L = 3.33 mH (LR)


Discussions:
 - UL is the only short OSEM in ITMY OSEMs.
 - ITMY have dumbells for magnets.
 - If UL magnet is off, ULSEN would not work. Something not magnetic is working for shadow sensing for UL? Dumbells?
 - ULSEN just sensing some coupling from other OSEMs?

Attachment 1: ULCoilInductance.JPG  3.962 MB  Uploaded Tue Jun 7 19:36:37 2022  | Hide | Hide all
ULCoilInductance.JPG
Attachment 2: ULCoilResistance.JPG  3.927 MB  Uploaded Tue Jun 7 19:36:47 2022  | Hide | Hide all
ULCoilResistance.JPG
Attachment 3: WrongSetting.JPG  4.060 MB  Uploaded Tue Jun 7 19:36:57 2022  | Hide | Hide all
WrongSetting.JPG
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