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Entry  Thu Oct 6 03:56:43 2016, ericq, Update, LSC, Revival Attempt 
    Reply  Tue Oct 11 02:48:43 2016, ericq, Update, LSC, Revival Attempts 
Message ID: 12547     Entry time: Tue Oct 11 02:48:43 2016     In reply to: 12535
Author: ericq 
Type: Update 
Category: LSC 
Subject: Revival Attempts 

Still no luck relocking, but got a little further. I disabled the output of the problematic PRM OSEM, it seems to work ok. Looking at the sensing of the PRMI with the arms held off, REFL165 has better MICH SNR due to its larger seperation in demod angle. So, I tried the slightly odd arrangement of 33I for PRCL and 165Q for MICH. This can indefinitely hold through the buzzing resonance. However, I haven't been able to find the sweet spot for turning on the CARM_B (CM_SLOW) integrator, which is neccesary for turning up the AO and overall CARM gain. This is a familiar problem, usually solved by looking at the value far from resonance on either side, and taking the midpoint as the filter module offset, but this didn't work tonight. Tried different gains and signs to no avail.

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