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Entry  Fri Feb 27 03:48:29 2015, Jenne, Update, LSC, PRMI locked during CARM scan REFL33Lock.pngREFL165Lock.png
    Reply  Fri Feb 27 21:16:10 2015, Jenne, Update, LSC, PRMI locked during CARM scan 8x
Message ID: 11082     Entry time: Fri Feb 27 03:48:29 2015     Reply to this: 11086
Author: Jenne 
Type: Update 
Category: LSC 
Subject: PRMI locked during CARM scan 

One of the things that I looked at tonight was whether or not I could hold the PRMI on REFL165 at CARM offset of 0, and it turns out that I can.  Hooray.  The next step was having a look to see if it is actually less noisy than the REFL33 lock.

I calibrated REFL33 and REFL165 to meters (I have the data to do the same for 11 and 55, but haven't done so yet).  This way, we can directly compare the signals from each PD. 

PD calibrations to meters [m/ct]
REFL 33 I 3.2e-11
REFL 33 Q 7.3e-12
REFL 165 I 9.5e-12
REFL 165 Q 1.2e-11

I scanned between +3 and -3 CARM digital offset (which we think is about 1nm/count while held on ALS), with a ramp time of 10 seconds.  I did this several times while the PRMI was locked on both REFL33 and REFL165. Here are the gps times for 8 examples where the PRMI did not lose lock during the sweep:

PD for lock CARM sweep GPS start time
REFL33 +3 -> -3 1109064431
REFL33 +3 -> -3 1109064516
REFL33 -3 -> +3 1109064614 (ended)
REFL33 -3 -> +3 1109064648
REFL165 +3 -> -3 1109064835
REFL165 -3 -> +3 1109064877
REFL165 +3 -> -3 1109064912
REFL165 -3 -> +3 1109064940

Here are screen shots from the first REFL33 sweep, and the first REFL165 sweep. DTT can't print 3 plots together, so I'll have to make this nicer later.  The top plot is the error signals, calibrated to meters.  The middle plot is the control signals, that need to be calibrated to Newtons.  The bottom plot is the arm powers, so you can see roughly where we were in the sweep.

We'd like to see a MIST simulation, or perhaps e2e, to see what the predicted disturbance is for each of the error signals during the CARM resonance.  We want to make sure that the loops are engaged for all of the degrees of freedom for the simulation.


Recipes for tonight:

REFL165 sometimes has a tough time catching lock by itself, but if you add either REFL33 or REFL55 error signals to the REFL165 signals, it'll catch, and then you can just remove the extra error signals.  Also, it doesn't stay locked very robustly unless you include the PRCL FM1 boost.

PRCL in PRFPMI, REFL55 I&Q MICH PRCL
Input Matrix 60* REFL55Q 6* REFL55I
Gain 3 -0.02
DoF trigger POP22I + 0.1*POPDC, 50 up 0.5 down POP22I + 0.1*POPDC, 50 up 0.5 down
FMs FM 4, 5 on FM 4, 5 on
FM trigger FM 2; 50 up, 0.5 down, 5 sec wait FM 1, 2, 9; 50 up, 0.5 down, 1 sec wait
Normalization none none
Output matrix 0.5*BS - 0.2625*PRM 1*PRM

 

PRCL in PRFPMI, REFL165 I&Q MICH PRCL
Input Matrix -0.6* REFL165Q 2.2* REFL165I
Gain 3 -0.02
DoF trigger POP22I + 0.1*POPDC, 50 up 0.5 down POP22I + 0.1*POPDC, 50 up 0.5 down
FMs FM 4, 5 on FM 4, 5 on
FM trigger FM 2; 50 up, 0.5 down, 5 sec wait FM 1, 2, 9; 50 up, 0.5 down, 1 sec wait
Normalization none none
Output matrix 0.5*BS - 0.2625*PRM 1*PRM
Attachment 1: REFL33Lock.png  93 kB  | Hide | Hide all
REFL33Lock.png
Attachment 2: REFL165Lock.png  97 kB  | Hide | Hide all
REFL165Lock.png
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