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40m Log |
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Tue Oct 8 18:35:09 2019, gautam, Update, LSC, Locking prep
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Wed Oct 9 18:15:26 2019, gautam, Update, LSC, PRMI 3f locking
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Wed Oct 9 22:02:58 2019, gautam, Update, LSC, REFL55 whitening issue
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Thu Oct 10 01:12:56 2019, gautam, Update, LSC, Locking studies
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Wed Oct 16 11:42:17 2019, gautam, Update, LSC, Poor separation of PRCL/MICH in 3f signals
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Thu Oct 17 11:19:28 2019, gautam, Update, LSC, Locking activity last night 
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Tue Oct 22 00:52:27 2019, gautam, Update, LSC, Locking updates
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Tue Oct 29 01:24:45 2019, gautam, Update, LSC, More locking updates 
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Tue Oct 29 15:13:19 2019, gautam, Update, LSC, More locking updates
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Wed Oct 30 01:27:00 2019, gautam, Update, LSC, More locking updates
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Wed Oct 30 11:53:41 2019, gautam, Update, LSC, MICH loop shape tuning 
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Wed Oct 30 17:08:40 2019, gautam, Update, LSC, POP22 investigation
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Mon Nov 4 15:29:47 2019, gautam, Update, LSC, POP signal path
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Mon Nov 4 16:06:58 2019, gautam, Update, LSC, POP optical path    
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Tue Nov 5 11:52:27 2019, gautam, Update, LSC, Locking notes
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Wed Nov 6 02:08:48 2019, gautam, Update, LSC, Locking updates
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Wed Nov 6 17:05:45 2019, gautam, Update, LSC, CARM calibration  
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Wed Nov 6 17:45:34 2019, gautam, Update, LSC, ~
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Mon Nov 18 21:04:38 2019, gautam, Update, LSC, Locking - some ideas
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Wed Nov 20 01:07:18 2019, gautam, Update, LSC, Locking - progress
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Wed Nov 20 12:14:17 2019, gautam, Update, LSC, Locking - progress
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Wed Nov 20 17:20:24 2019, Yehonathan, Update, LSC, QPD Investigation
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Wed Nov 20 17:52:00 2019, gautam, Update, LSC, QPD MEDM screen update  
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Wed Nov 20 21:29:28 2019, gautam, Update, LSC, PRG ~13
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Fri Nov 22 00:54:14 2019, gautam, Update, LSC, locking notes
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Mon Nov 25 19:11:22 2019, gautam, Update, LSC, ALS noise re-look
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Wed Nov 27 23:24:01 2019, gautam, Update, LSC, No shaking but no inspiration either
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Sun Dec 1 13:38:48 2019, rana, Update, LSC, No shaking but no inspiration either
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Tue Dec 3 00:03:57 2019, gautam, Update, LSC, Green ALS also shows elevated noise with high arm buildup
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Wed Dec 4 19:54:27 2019, gautam, Update, LSC, A look to the past
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Thu Dec 5 01:54:39 2019, gautam, Update, LSC, Partial CM board path engaged
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Fri Dec 6 00:02:48 2019, gautam, Update, LSC, What is the correct way to set the 3f offsets?
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Fri Nov 15 12:08:04 2019, gautam, Update, LSC, POPDC whitening board
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Tue Oct 29 17:40:48 2019, gautam, Update, LSC, More locking updates 
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Message ID: 15080
Entry time: Fri Dec 6 00:02:48 2019
In reply to: 15075
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Author: |
gautam |
Type: |
Update |
Category: |
LSC |
Subject: |
What is the correct way to set the 3f offsets? |
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Summary:
I made it to 0 CARM offset, PRMI locked a bunch of times today. However, I could not successfully engage the AO path.
Details:
Much of the procedure is scripted, here is the rough set of steps:
- Transition control of the arms from IR signals to ALS signals.
- DC couple the ITM oplev servos
- Burt-restore the settings for PRMI locking with REFL165I-->PRCL, REFL165Q-->MICH, and then enable the MICH_B / PRCL_B locking servos.
- Add some POPDC to the PRMI triggering (nominally only POP22_I) to let these loops be locked while POP22_I fluctuates wildly when we are near the CARM=0 point.
- Zero the CARM offset.
- Adjust the CARM_A/DARM_A offsets such that CARM_B/DARM_B are fluctuating symmetrically about 0.
- CARM_B gain --> 1.0, to begin the RF blend.
- Prepare to hand the DC control authority to ALS by turning off FM1 in the CARM filter bank, and turning ON an integrator in the CARM_B filter.
As I type this out, I realized that I was incorrectly setting offsets to maximize the arm powers by adjusting CARM/DARM offsets as opposed to CARM_A / DARM_A offsets. Tried another round of locking, but this time, I can't even turn the integrator on to get the arms to click into somewhat stable powers.
One thing I noticed is that depending on the offsets I put into the 3f locking loops, the mean value of REFL11 and AS55 when the ALS CARM/DARM offsets are zeroed changes quite significantly. What is the correct condition to set these offsets? They are different when locking the PRC without arm cavities, and also seem to change continuously with CARM offset. I am wondering if I have too much offset in one of the vertex locking loops? |