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Entry  Tue Feb 3 04:01:55 2015, diego, Update, LSC, CM servo & AO path status CARM_03-02-2015_031754.pdf
    Reply  Tue Feb 3 16:36:33 2015, ericq, Update, LSC, CM servo & AO path status yarmAO.pdf
       Reply  Mon Feb 9 17:47:17 2015, diego, Update, LSC, CM servo & AO path status 
Message ID: 10991     Entry time: Mon Feb 9 17:47:17 2015     In reply to: 10969
Author: diego 
Type: Update 
Category: LSC 
Subject: CM servo & AO path status 

I wrote the script with the recipe we used, using the Yarm and AS55 on the IN2 of the CM board; however, the steps where the offset should be reduced are not completely deterministic, as we saw that the initial offset (and, therefore, the following ones) could change because of different states we were in. In the script I tried to "servo" the offset using C1:LSC-POY11_I_MON as the reference, but in the comments I wrote the actual values we used during our best test; the main points of the recipe are:

  • misalign the Xarm and the recycling mirrors;
  • setting up CARM_B for POY11 locking and enabling it;
  • setting up CARM_A for CM_SLOW;
  • setting up the CM_SLOW filter bank, with only FM1 and FM4 enabled;
  • setting up the CARM filter bank: FM1 FM2 FM6 triggered, only FM3 and FM5 on; usual CARM gain = 0.006;
  • setting up CARM actuating on MC2;
  • turn off the violin filter FM6 for MC2;
  • setting up the default configuration for the Common Mode Servo and the Mode Cleaner Servo; along with all the initial parameters, here is where the initial offset is set;
  • turn on the CARM output and, then, enable LSC mode;
  • wait until usual POY11 lock is acquired and, a bit later, transition from CARM_B to CARM_A;
  • then, the actual CM_SLOW recipe:
    • CM_AO_GAIN = 6 dB;
    • SUS-MC2_LSC FM6 on (the 300:80 filter);
    • CM_REFL2_GAIN = 18 dB;
    • servo CM_REFL_OFFSET;
    • CM_AO_GAIN = 9 dB;
    • CM_REFL2_GAIN = 21 dB;
    • servo CM_REFL_OFFSET;
    • CM_REFL2_GAIN = 24 dB;
    • servo CM_REFL_OFFSET;
    • CM_REFL2_GAIN = 27 dB;
    • servo CM_REFL_OFFSET;
    • CM_REFL2_GAIN = 31 dB;
    • servo CM_REFL_OFFSET;
    • CM_AO_GAIN = 6 dB;
    • SUS-MC2_LSC FM7 on (the :300 compensating filter);

I tried the procedure and it seems fine, as it did during the tries Q and I made; however, since it touches many things in many places, one should be careful about which state the IFO is into, before trying it.

The script is in scripts/CM/CM_Servo_OneArm_CARM_ON.py and in the SVN.

 

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