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Reports until 21:10, Tuesday 15 September 2015
LHO VE (VE)
sheila.dwyer@LIGO.ORG - posted 21:10, Tuesday 15 September 2015 - last comment - 22:03, Tuesday 15 September 2015(21564)
Vaccum guages read out in beckhoff

Sheila, Evan

Last night, we had a beckhoff problem at end Y that started at 5:44 UTC (alogs: 21555 and comments). 

The ESD high voltage remained on all night, even though the vacuum guages that are meant to turn it off were not communicating. 

The first screen shot shows the beckhoff readout vacuum guage (H1:VAC-EY_Y4_PT425_PRESS_TORR) , which was reporting a constant value all night since the start of the beckhoff problems.  It was alo reported as "valid" durring this time.  Before Fil, Vern Nutsinee and I went out to EY, Patrick and I were attempting to clear the beckhoff errors by reiniting all the modules.  This must have been partially sucsesfull around 18:33 UTC, when the pressure reading dropped to zero, the channel is no longer reported as valid, and the ESD high voltage gets turned off.  This is why we found the high voltage off even though it had been on all night. 

One other concerning thing is that the values reported by the beckhoff readout gauge has changed before and after the problems.  the normal vacuum guage does not see such a big change.  Also, it seems that Y5 was not working until we swapped the chassis today. 

Note for the operators:  There was no indication of this problem on the CDS overview screen.  You can watch for this problem by opening up an ALS PFD screen (for example, see screenshot) and checking that the RF MON and LO mon values are changing.  If they are not changing, you may need to call someone. Ed has this screen open for both end stations on he ops station. 

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patrick.thomas@LIGO.ORG - 22:03, Tuesday 15 September 2015 (21565)
So the vacuum pressure was flatlined and the diagnostic channel reported it as valid? Not good.
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