40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  40m Log  Not logged in ELOG logo
Entry  Wed Aug 16 20:01:03 2017, gautam, Update, General, SUS model ASC input weirdness ITMX_ASC.png
    Reply  Fri Aug 18 21:58:35 2017, gautam, Update, General, SUS model ASC input weirdness ITMXP.pngASC_model_outmatrix.pngASC_medm.pngASC_outMat.png
Message ID: 13221     Entry time: Wed Aug 16 20:01:03 2017     Reply to this: 13228
Author: gautam 
Type: Update 
Category: General 
Subject: SUS model ASC input weirdness 

I'm not sure if this has something to do with the model restarts / new RCG, but while I was re-enabling the MC watchdogs, I noticed the RMS sensor voltage channels on ITMX hovering around ~100mV, even though local damping was on (in which configuration I would expect <1mV if everything is working normally).  I was confused by this behaviour, and after staring at the ITMX suspension screen for a while, I noticed that the input to the "ASCP" and "ASCY" servos were "-nan", and the outputs were 10^20 cts frown (see Attachment #1).

Digging a little deeper, I found that the same problem existed on ITMY, ETMX, ETMY, PRM (but not BS or SRM) - reasons unknown for now.

I have to check where this signal is coming from, but for now I just turned the "ASC Input" switch off. More investigation to be done, but in the meantime, ASS dither alignment may not be possible.

After consulting with Jamie, I have just disabled all outputs to the suspensions other than local damping loop outputs. I need to figure out how to get this configuration into the safe.snap file such that until we are sure of what is going on, the models start up in this safer configuration.

gedit 28 Oct 0026: Seems like this problem is seen at the sites as well. I wonder if the problem is related.

Attachment 1: ITMX_ASC.png  58 kB  | Hide | Hide all
ELOG V3.1.3-