jason.oberling@LIGO.ORG - posted 11:08, Tuesday 29 October 2019 - last comment - 11:18, Tuesday 29 October 2019(52763)
PSL PMC/RefCav Beam Alignment Tweak and Power Watchdog Reset (FAMIS 10734)
In advance of the imminent start of O3b, I have tweaked the beam alignment into both the PMC and FSS RefCav. All tweaking was done with the ISS OFF.
- PMC
- Before:
- Trans: 52.5 W
- Refl: 11.6 W
- After:
- Trans: 52.8 W
- Refl: 11.3 W
- Before:
- FSS RefCav
- TPD
- Before: 4.2 V
- After: 4.8 V
- TPD
After turning the ISS back on, I noticed the % diffracted power was down around 1.4%; this is below our 2% minimum, so I adjusted the ISS Ref Signal from -2.01V to -2.0V, which brought the % diffracted power back up to ~2%. This change was accepted in both the safe.snap and OBSERVE.snap SDF files. With the ISS back ON the PMC is now transmitting 53.3 W.
I also reset both PSL power watchdogs at 18:05 UTC (11:05 PDT). This completes FAMIS 10734.
In addition to the above, while resetting the PSL power watchdogs the PSL Beckhoff Status screen was showing a 'Check Diode Chiller' warning. Heeding said warning, I checked on the diode chiller; it was showing a 'Low Water Level' warning, which went away while I was taking the cap off of the reservoir (this is an indication that the chiller is right on the edge of being low on water; the timing with me removing the cap was coincidence). I added 500mL of water to the diode chiller and did not observe the low water level warning again.