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Message ID: 10928     Entry time: Thu Jan 22 02:56:07 2015
Author: ericq 
Type: Update 
Category: IOO 
Subject: FSS input offset adjusted 

Since Rana's overhaul of the IMC, the FSS input offset had been sitting at zero. 

Over the last day or so, I had noticed the MC refl wall striptool trace looking noisier, and earlier this evening, we were suffering from a fair amount of downtime due to IMC unlocks, and failure to autolock for times on the order of ten minutes. 

While we had used ezcaservo for this in the past, I set the FSS offset manually tonight. Namely, I popped open a dataviewer trace of MC_F, and scanned the FSS offset to make MC_F go to zero. It required a good amount of offset, 4.66 V according to the FSS screen. I did this while the FSS slow servo was on, which held the FSS Fast output at zero. 

That was four hours ago; MC_F is still centered on zero, and we have not had a single IMC unlock since then. The MC refl trace is thinner too, though this may be from nighttime seismic. 

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