Reports until 13:22, Monday 05 June 2017
H1 CAL (CAL)
travis.sadecki@LIGO.ORG - posted 13:22, Monday 05 June 2017 (36663)
End Y PCal PD output step

JeffK, TravisS

We noticed a DIAG_MAIN message reporting that the EY PCal RX PD was more than 1% out of normal.  We had this warning put in place to indicate if clipping we have seen previously at EY returns.  This time, however, it turned out not to be clipping, which is a good thing, but rather that something had happened that railed the OFS loop.  Trending the TX, RX, and OFS PDs showed that they all railed at the same time (of course) on June 2.  Talking to Sheila and looking at Ed's OPS shift summary from that day, there was a lot of electronics work done at EY earlier in the day.  Not conclusive that the two things are related, but definitely possible.

Hopefully this doesn't happen very often, but if it does, the fix is very easy.  Open the PCal screen for the end station of concern (from the CAL tab on the Sitemap), click Shutter 'OFF' button circled in the attached screenshot, then click the Shutter 'ON' button.  This should fix the issue.  If it does not, please contact your friendly neighborhood PCal person.

Images attached to this report