Lockloss from OMC_Whitening due to ETMX Watchdog trips
HEPI, ISI, and SUS has tripped again at 18:15 UTC. This is now a trend that has happened 3 times in the last 24 hours. It happened twice on Oli's shift.
The ground motion out at EX is very slightly elevated due to a slight increase in wind since this morning. But the wind doesn't seem anywhere near high enough to cause all 3 of the WD to trip like this.
The EX Wind Fence is still standing as well.
I've attached the Lockloss plots and the Log to this Alog.
Link to Ryan's post where he has found some more evidence of something weird going on.
After speaking to Jim,
There seems to be a tidal system that may have an issue, which is tripping HEPI, ISI & SUS.
I've contacted Danielle as Ive heard he has a working knowledge of the Tidal system.
It looks like the EX trips are being caused by the ISC signal to EX HEPI for tidal offloading. Attached trends are the last trip at EX. Top two rows are ETMX SUS and ISI ST1 WD, third row is the ISC signal to ETMX. Fourth row is the HEPI WD, and bottom row are the HEPI actuators. Looks like there is some kick in the ISC signal to HEPI that trips HEPI, then takes out the ISI and SUS. The ISC off set is about 40 microns, but tries to push HEPI about 2microns in about 1/4 second.
This transient signal originates in DARM (probably as a result of a lock loss) and makes it into HEPI throught the SUS offloading from L3 to L1, and then through the tidal offloading into HEPI. We added a 0.3 Hz pole (FM2) to the H1:HPI-ETMX_ISCINF_LONG filter module. This will low pass filter the tidal offloading path and hopefully prevent HEPI trips.