kyle.ryan@LIGO.ORG - posted 19:34, Monday 21 October 2019 - last comment - 20:40, Monday 21 October 2019(52606)
HAM6 indicated pressure fuctuating wildly
I've noticed over the past hour or so that HAM6's pressure is fluctuating by, at least a factor of 4 -> I spoke with Georgia on the phone and she trended HAM6 pressure and confirmed -> I am heading out to the site to investigate.
Comments related to this report
georgia.mansell@LIGO.ORG - 19:39, Monday 21 October 2019 (52607)
I checked out the turbo and backing cart at HAM6 and the turbo RPM and temperature, as well as, the foreline pressure are as expected and are stable. As can be seen in the attached graph of PT110 (second data) the indicated pressure spikes are not followed by "real" pump down curve profiles. Thus, this recent erratic behavior is not due to real pressure flucuations but, rather, is the result of the transducer or the data processing. I'll leave it to others to consider the pros and cons of changing or bypassing the HV interlock should these indicated pressure fluctuations result in nuisance interlock trips.
Attaching a trend of PT-110, the gauge at HAM6. At 01:39 UTC the pressure reading started fluctating wildly.
At 01:50 UTC the fast shutter closed, so presumably the high voltage got tripped off in HAM6.
At 02:28 UTC we got a verbal alarm in the control room that the vacuum pressure was high at HAM 6.
I checked out the turbo and backing cart at HAM6 and the turbo RPM and temperature, as well as, the foreline pressure are as expected and are stable. As can be seen in the attached graph of PT110 (second data) the indicated pressure spikes are not followed by "real" pump down curve profiles. Thus, this recent erratic behavior is not due to real pressure flucuations but, rather, is the result of the transducer or the data processing. I'll leave it to others to consider the pros and cons of changing or bypassing the HV interlock should these indicated pressure fluctuations result in nuisance interlock trips.