georgia.mansell@LIGO.ORG - posted 20:36, Thursday 31 October 2019 - last comment - 14:58, Friday 01 November 2019(52856)
ITM ESD high voltage untripped 01:50 UTC
We got to TRANSITION_FROM_ETMX (where DARM control is temporarily handed off from ETMX L1 L2 L3 to ETMY L1 L2 + ITMX L3) and found that the guardian would not complete the transition as the ITMX ESD high voltage was off (nice catch in the guardian!)
Dan went to the mezzanine and pressed the red button on the box above the HV supply to untrip the high voltage.
It seems like it's been tripped since 00:14 UTC October 31.
Kyle, Fil, Sheila, Rahul
To investigate further on this, I trended the following two channels to see Guardian request for HV at ITMX,
H1:SUS-ITMX_L3_ESDAMON_DC_OUT16 #shows the status if HV has been supplied
H1:FEC-28_DAC_OUTPUT_7_0 #where Guardian is requesting HV
Last evening Guardian requested for HV at 0.1.30 UTC, however HV was tripped (can been seen in the ndscope plot attached). On 30 Oct, this was working fine, which can be seen in the same plot.
We trended (attached) the HAM (7 and 8) vacuum data (PT 170, PT 180) to look for any drop in pressure which could potentially trip the HV supply. The pressure was fine, however Kyle thinks that the glitches in the gauges could be possible. According to Fil, the safety relays (between vacuum gauges and HV supply) could be another possibility.