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Entry  Fri Aug 15 20:38:17 2014, ericq, Update, General, ELOG dump 
    Reply  Wed Jan 7 21:13:35 2015, rana, Update, General, inane LSCoffsets script removed 
       Reply  Thu Jan 8 19:41:50 2015, ericq, Update, General, inane LSCoffsets script removed 
Message ID: 10405     Entry time: Fri Aug 15 20:38:17 2014     Reply to this: 10874
Author: ericq 
Type: Update 
Category: General 
Subject: ELOG dump 

 A few things that I have neglected to ELOG yet:

  • scripts/offsets/LSCoffsets is a new script that uses ezcaservo to set FM offsets of our LSC PDs. It still warns about large changes, and lets you revert. It reads the FM gain to pick the right gain for the ezcaservo call. 

  • MC refl DC was all over the place today, and has recently been "fuzzier" on the wall StripTool than I like. I touched the MC2 pointing a little bit, and the WFS seemed to find a sweet spot where the refl got steady back at around and under 0.5. I then ran "offload WFS" to try and stay there. 

  • Incidentally, the PMC transmission drifted up to 0.81 at some point today. This is weird, since not too long ago, we were not able to reach this level even with careful alignment. This coincided with the MC power being back up to ~17k, and arms locking at around 0.95. 

  • Last week I quickly tried cranking up the x-end green modulation frequency to ~1.3MHz (corresponding to a notch in the PZT AM response), and using a 550k lowpass on the mixer output, instead of a 70k, to try to buy more phase and increase the UGF. It didn't work. I didn't have a way to tune the mixer phase angle, and the mixer output was super noisy, but there were instants where I could convince myself that a mode was briefly locked to the arm... I'm going to do the Right Thing and characterize the loop properly, to figure out how to get at least 10kHz of control bandwidth out of these things. 

ELOG V3.1.3-