Laser restarted without issue (at first, more on that below). TJ had to reset the noise eater, and after that all the PSL subsystems came back without issue.
Once everything was recovered TJ noticed the Head 1-4 Flow warning light blinking. Sure enough, on the Chiller Beckhoff screen the flow through the laser heads was flashing; there is a range above the trip point that the system alarms before tripping. We observed this for several minutes, and noticed that the flow reading for head 3 was fluctuating between 0.5 and 0.6 lpm, causing the warning alarm to flash. Unfortunately there is not much that can be done about this remotely. TJ is going to continue locking the IFO and we hope this will sort itself out.
Some further forensics. Head 2 was the culprit this time, dropping below the trip point and therefore tripping the "Head 1-4 Flow" interlock. The first attachment shows the 3 active laser head flow sensors and the "Head 1-4 Flow" interlock. The second attachment is a slightly zoomed in view of the Head 3 flow sensor signal. Nothing else with the system looks suspect.
Edit: Uploaded the wrong image files; this has been corrected.
Laser restarted without issue (at first, more on that below). TJ had to reset the noise eater, and after that all the PSL subsystems came back without issue.
Once everything was recovered TJ noticed the Head 1-4 Flow warning light blinking. Sure enough, on the Chiller Beckhoff screen the flow through the laser heads was flashing; there is a range above the trip point that the system alarms before tripping. We observed this for several minutes, and noticed that the flow reading for head 3 was fluctuating between 0.5 and 0.6 lpm, causing the warning alarm to flash. Unfortunately there is not much that can be done about this remotely. TJ is going to continue locking the IFO and we hope this will sort itself out.
I filed FRS 7537 for this trip.
Some further forensics. Head 2 was the culprit this time, dropping below the trip point and therefore tripping the "Head 1-4 Flow" interlock. The first attachment shows the 3 active laser head flow sensors and the "Head 1-4 Flow" interlock. The second attachment is a slightly zoomed in view of the Head 3 flow sensor signal. Nothing else with the system looks suspect.
Edit: Uploaded the wrong image files; this has been corrected.