brian.lantz@LIGO.ORG - posted 17:11, Monday 21 September 2015 - last comment - 14:19, Thursday 24 September 2015(21755)
HAM5 Rogue Excitation alarm annoyance from bad channel readback
Folks have been complaining that the HAM5-ISI Rogue Excitation monitor is a pain. (see e.g. https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=21474) It looks like the coil-voltage-readback monitor for the V2 coil is busted somewhere, and so the monitor is sitting around -500 counts all the time. Hugh gave me the GPS time for a recent earthquake, and in the attached plot you can see the watchdog trip from normal (state 1) to damp-down (state 2) at T+3 seconds. The coil voltages come down pretty quickly. Then the WD goes to state 4 (full trip) about 3 seconds later and the coil drive monitors (except V2) get quite small. The rogue excitation alarm goes off about 3 seconds after that, because the V2 monitor has not fallen to abs(Vmon) < +100 counts. The V2 monitor just sort of sits at ~-500 counts all the time. I'm pretty sure the V2 coil drive is working, otherwise the HAM5-ISI platform would act very poorly. I'm guessing the problem is somewhere in the readback chain. Note - the channels I use for this are all Epics channels, so the timing is a bit crude and the voltages are sort of jumpy. The channels are: H1:ISI-HAM5_ERRMON_ROGUE_EXC_ALARM H1:ISI-HAM5_CDMON_H1_V_INMON H1:ISI-HAM5_CDMON_H2_V_INMON H1:ISI-HAM5_CDMON_H3_V_INMON H1:ISI-HAM5_CDMON_V1_V_INMON H1:ISI-HAM5_CDMON_V2_V_INMON H1:ISI-HAM5_CDMON_V3_V_INMON H1:ISI-HAM5_WD_MON_STATE_INMON I've also attached screenshots of the "coil drive voltage too big" calculation and the "rogue excitation alarm generation" calculation from the HAM-ISI master model
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I've added integration issue 1127 on this https://services.ligo-wa.caltech.edu/integrationissues/show_bug.cgi?id=1127
I think I've got all the colors sorted out and pretty sure it looks like H2 Monitor isn't working either. At first I thought it was just zero on the plot but I don't think so. At least it won't cause this problem and being H2 may help find the problem.