On the PSL SYSSTAT medm, we had the Oscillator/Head 1-4 flow error in a Fault/red state. Jason said this meant that we had a "glitch in laser head flow sensors". Jason brought back the PSL remotely. I topped off the PSL Chiller (the cap did NOT pop off) with 375mL of water.
ISS was oscillating afterward, so we adjusted the REFSIGNAL (from -1.1 to -1.5).
But later noticed DIAG_MAIN message saying the NOISE_EATER was faulted. So I went out to toggle this on/off.
ISS was oscillating again and this time took REFSIGNAL to a more reasonable -1.08.
13:58 Back to LOCK ACQUISITION
FRS #7460 Filed For ~1hr of CORRECTIVE_MAINTENANCE DOWN time.
jason.oberling@LIGO.ORG - 09:19, Wednesday 22 February 2017 (34316)
Cause appears to be a trip of the Laser Head 1-4 Flow interlock, specifically Head 2. The first attachment shows the 3 laser head flow rates (the 4th is currently being forced to a value in the Beckhoff software, so cannot contribute to the trip). It is clear that head 2 became erratic and began to drop in flow, eventually passing below the trip point and tripping the laser. The 2nd attachment shows a zoomed in view of only the Head 2 flow. Possible debris passing through the flow sensor?
On the PSL SYSSTAT medm, we had the Oscillator/Head 1-4 flow error in a Fault/red state. Jason said this meant that we had a "glitch in laser head flow sensors". Jason brought back the PSL remotely. I topped off the PSL Chiller (the cap did NOT pop off) with 375mL of water.
13:58 Back to LOCK ACQUISITION
FRS #7460 Filed For ~1hr of CORRECTIVE_MAINTENANCE DOWN time.
Cause appears to be a trip of the Laser Head 1-4 Flow interlock, specifically Head 2. The first attachment shows the 3 laser head flow rates (the 4th is currently being forced to a value in the Beckhoff software, so cannot contribute to the trip). It is clear that head 2 became erratic and began to drop in flow, eventually passing below the trip point and tripping the laser. The 2nd attachment shows a zoomed in view of only the Head 2 flow. Possible debris passing through the flow sensor?