This seems like another example of the SR3 problem. (alog 32220 FRS 6852)
If you want to check for this kind of lockloss, zoom the time axis right around the lockloss time to see if the SR3 sensors change fractions of a second before the lockloss.
Images attached to this comment
jeffrey.kissel@LIGO.ORG - 17:28, Tuesday 06 December 2016 (32274)CDS, DetChar, Lockloss, SUS
J. Kissel, B. Weaver, T. Sadecki
Just for reference, I include a lockloss that was definitely *not* caused by the SR3 glitching for future comparison and distinction of whether this SR3 glitch has happened or not.
Also, remember, although the OPS wiki's instructions suggest that one must and can only use lockloss2, not everyone has the alias yet for this more advanced version. You can make the plots, and do everything you need with the more basic version:
lockloss -c /ligo/home/ops/Templates/Locklosses/channels_to_look_at_SR3.txt select
It would also be great to get the support of @DetChar on this one. The fear is that these glitches begin infrequently, but get successively more frequent. Once they do, we should consider replacing electronics.
The fishy thing, though, is that LF and RT are on separate electronics chains, given the cable layout of HAM5 (see D1101917). Maybe these glitches are physical motion? Maybe with statistics of two, it's unclear whether it's that LF and RT just *appear* to be the culprit whether it may be a random set of OSEMs glitching.
Images attached to this comment
betsy.weaver@LIGO.ORG - 18:27, Tuesday 06 December 2016 (32279)
See my note in alog 32220, namely that Sheila and I looked again and we see that the glitch is on the T1 and LF coils, which share a line of electronics. The second lockloss TJ started with in this log (12/06) are somewhat unconclusively linked to SR3 - no "glitches" like the first one 12/05, but instead all 6 top mass SR3 OSEMs show motion before lockloss.
Sheila, Betsy
betsy.weaver@LIGO.ORG - 19:01, Tuesday 06 December 2016 (32280)
Attached is a ~5 day trend of the SR3 top stage OSEMs. T1 and LF do have an overall step in the min/max of their signals which happened at the time of that lockloss which showed the SR3 glitch (12/05 16:02 UTC)...
betsy.weaver@LIGO.ORG - 19:03, Tuesday 06 December 2016 (32281)
But don't worry, we are back to Observing at 10:36 UTC.
I haven't seen anything of note for the lockloss. I checked the usual templates, with some screenshots of them attached.
This seems like another example of the SR3 problem. (alog 32220 FRS 6852)
If you want to check for this kind of lockloss, zoom the time axis right around the lockloss time to see if the SR3 sensors change fractions of a second before the lockloss.
See my note in alog 32220, namely that Sheila and I looked again and we see that the glitch is on the T1 and LF coils, which share a line of electronics. The second lockloss TJ started with in this log (12/06) are somewhat unconclusively linked to SR3 - no "glitches" like the first one 12/05, but instead all 6 top mass SR3 OSEMs show motion before lockloss.
Sheila, Betsy
Attached is a ~5 day trend of the SR3 top stage OSEMs. T1 and LF do have an overall step in the min/max of their signals which happened at the time of that lockloss which showed the SR3 glitch (12/05 16:02 UTC)...