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Entry  Wed Oct 30 00:02:25 2013, Jenne, Update, LSC, LSC demod boards need some thought 
    Reply  Wed Oct 30 01:22:56 2013, Jenne, Update, LSC, REFL 165 demod phase adjusted 
       Reply  Wed Oct 30 01:44:13 2013, Jenne, Update, LSC, MICH and PRCL gains adjusted (Config file saved) 
          Reply  Wed Oct 30 03:36:51 2013, Jenne, Update, LSC, MICH and PRCL UGFs change with ALS enabled 
             Reply  Mon Nov 4 15:46:17 2013, Jenne, Update, LSC, Thoughts and Conclusions from last week's PRMI+2arms attempt 12x
                Reply  Tue Nov 5 19:39:27 2013, Jenne, Update, LSC, OpLev time series OpLevs_during_PRMI_2arms.pdf
    Reply  Wed Oct 30 03:33:17 2013, Rana, Update, LSC, LSC demod boards need some thought 0309.png
       Reply  Wed Oct 30 08:32:55 2013, Evan, HowTo, Computer Scripts / Programs, matplotlibrc 
Message ID: 9317     Entry time: Wed Oct 30 03:36:51 2013     In reply to: 9314     Reply to this: 9338
Author: Jenne 
Type: Update 
Category: LSC 
Subject: MICH and PRCL UGFs change with ALS enabled 

Masayuki was able to hold both arms off-resonance with ALS long enough for me to lock the PRMI (arms still held off resonance), and take a set of transfer functions.

MICH gain is still -2.0, PRCL gain is still 0.070, which, with the ETMs misaligned, gave me UGFs of 70 for MICH and 180 for PRCL.

Now, however, with the ETMs aligned, but arms held off resonance with ALS, the UGFs have been lowered by a factor of 2 in frequency!  What is doing this??  MICH is now 40 Hz, and PRCL is now 80 Hz.

We measured the MICH and PRCL loops for several arm powers, and there was no change, at least until the arms were both resonating with powers of ~4 . 

After misaligning the ETMs, I remeasured the loops, and the UGFs went back up to where they started.

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