Reports until 06:18, Tuesday 31 October 2017
H1 PSL (PSL)
peter.king@LIGO.ORG - posted 06:18, Tuesday 31 October 2017 - last comment - 10:38, Tuesday 31 October 2017(39220)
Laser trip 
Richard came into my office this morning to tell me that the laser was off.  Pulled up the laser status
screen to find that power watchdog was activated ~12 hours 20 minutes ago (~6 pm Monday).  The laser
was brought back.
Comments related to this report
jason.oberling@LIGO.ORG - 10:28, Tuesday 31 October 2017 (39227)
Link

As Peter says, the laser tripped due to a trip of the power watchdog.  Looking at the relevant channels at the time of the trip, the 35W FE watchdog tripped first, with the HPO watchdog following ~6 seconds later due to the loss of the FE (see attachment).  Beyond that, I can't find any reason for the FE power watchdog to have tripped.  All channels for the FE and NPRO appear to be behaving normally up to the trip, then everything cuts off (as it should with a power WD trip).  Unclear at this time why the FE watchdog tripped.  Maybe another occurance occurrence of the mysterious NPRO shut down that we can't explain but seem to see a few times a year?

Edit for spelling at 10:30 PDT.

Images attached to this comment
jason.oberling@LIGO.ORG - 10:38, Tuesday 31 October 2017 (39229)
Link

Filed FRS 9337 for this trip.

We usually blame NPRO shut-downs on the UPS the NPRO is plugged into.  Maybe that's what happened here again?