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Entry  Fri Jul 5 20:57:04 2019, Koji, Update, SUS, Another M7.1 EQ Screenshot_from_2019-07-05_21-03-06.png
    Reply  Fri Jul 5 21:53:10 2019, Koji, Update, SUS, Another M7.1 EQ 
       Reply  Fri Jul 5 22:21:13 2019, Koji, Update, SUS, Another M7.1 EQ Screenshot_from_2019-07-05_22-19-57.png
          Reply  Fri Jul 12 07:37:48 2019, gautam, Update, SUS, M4.9 EQ in Ridgecrest 56.pngITMXunstick.pngITMX_UL.pdf
             Reply  Tue Jul 16 15:00:03 2019, gautam, Update, SUS, Multiple small EQs 
Message ID: 14755     Entry time: Fri Jul 12 07:37:48 2019     In reply to: 14729     Reply to this: 14763
Author: gautam 
Type: Update 
Category: SUS 
Subject: M4.9 EQ in Ridgecrest 

All suspension watchdogs were tripped ~90mins ago. I restored the damping. IMC is locked.

ITMX was stuck. I set it free. But notice that the UL Sensor RMS is higher than the other 4? I thought ITMY UL was problematic, but maybe ITMX has also failed, or maybe it's coincidence? Something for IFOtest to figure out I guess. I don't think there is a cable switch between ITMX/ITMY as when I move the ITMX actuators, the ITMX sensors respond and I can also see the optic moving on the camera.

Took me a while to figure out what's going on because we don't have the seis BLRMS - i moved the usual projector striptool traces to the TV screen for better diagnostic ability.

Update 16 July 1515: Even though the RMS is computed from the slow readback channels, for diagnosis, I looked at the spectra of the fast PD monitoring channels (i.e. *_SENSOR_*) for ITMX - looks like the increased UL RMS is coming from enhanced BR-mode coupling and not of any issues with the whitening switching (which seems to work as advertised, see Attachment #3, where the LL traces are meant to be representative of LL, LR, SD and UR channels).

Attachment 1: 56.png  88 kB  Uploaded Fri Jul 12 08:39:21 2019  | Hide | Hide all
Attachment 2: ITMXunstick.png  32 kB  Uploaded Fri Jul 12 09:00:43 2019  | Hide | Hide all
Attachment 3: ITMX_UL.pdf  55 kB  Uploaded Tue Jul 16 16:21:26 2019  | Hide | Hide all
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