40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
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Entry  Tue Apr 19 18:10:10 2022, Paco, Update, BHD, Part V of BHR upgrade - POX11 path, LO path, and ITMX Oplev DJI_0167.JPGDJI_0169.JPGDJI_0168.JPG
    Reply  Wed Apr 20 08:20:22 2022, Paco, Update, BHD, Part V of BHR upgrade - PR2 weirdness 
       Reply  Wed Apr 20 18:50:03 2022, Koji, Update, BHD, Part V of BHR upgrade - PR2 weirdness Screenshot_2022-04-20_18-46-11.png
    Reply  Thu Apr 21 16:49:01 2022, Paco, Update, BHD, Part V of BHR upgrade - BS Oplev + LO1 offset 
       Reply  Thu Apr 21 18:42:47 2022, Tega, Update, BHD, Part V of BHR upgrade - Align LO and AS beams to BHD BS 
          Reply  Thu Apr 21 20:33:31 2022, Koji, Update, BHD, AS1 UR OSEM problem localized in the chamber Screenshot_from_2022-04-21_20-13-13.png
             Reply  Fri Apr 22 12:03:09 2022, Tega, Update, BHD, AS1 UR OSEM problem localized in the chamber 
                Reply  Fri Apr 22 12:15:08 2022, Anchal, Update, BHD, Cable post installation 
                   Reply  Mon Apr 25 16:57:57 2022, Anchal, Update, BHD, Cable post installation 
Message ID: 16792     Entry time: Wed Apr 20 18:50:03 2022     In reply to: 16789
Author: Koji 
Type: Update 
Category: BHD 
Subject: Part V of BHR upgrade - PR2 weirdness 

It seemed that it comes from the servo oscillation. This does not happen when the output limitters were set to be 100-ish. But even so the gains looked quite low.

I turned on the Cheby rool-offs for all the DOFs, and this allowed me to increase the damping gain A LOT.
The gains were 2~5 but now they are now 20-25 for the face OSEMs and 150 for SD.

The attached is the example of the damping when all the damping loops are on.

I think we need to tune the servo loops carefully for all the SUSs by actually looking at the openloop transfer functions rather than a personal feeling. => To Do

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Screenshot_2022-04-20_18-46-11.png
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