cheryl.vorvick@LIGO.ORG - posted 15:00, Thursday 07 July 2016 - last comment - 15:16, Thursday 07 July 2016(28245)
Ops Day Summary: H1 is relocking well, but cannot engage ISS 2nd loop
State of H1: locked at 25W, but no ISS 2nd loop
Activities:
- Peter King - PSL - FSS tuning
- Kyle - MX - vacuume work
- Robert - electronics room
- JimW - HAM2 blend filter update
Glitches:
- PSL AC left on - now off
- Confusion over a guardian state - lock loss
- ISS 2nd loop is not working - currently being worked on
Special Instructions:
- SRM human servo - found on ASC medm tab, SRM POP90 - use to keep the signal low and smooth (offsets in guardian were for 40W, but Sheila fixed by taking them out)
I did turn the AC off when I left the enclosure this morning. It took a few tries but the facility control unit said they were off. Also when I went to go in this morning, all the HEPA fan speeds were set to 20% instead of the 100% (they are off when no one is inside).After one lock loss FSS started oscillating (PZT signal H1:PSL-FSS_FAST_MON_OUTPUT was going rail to rail).
Bringing down the fast gain by 1dB (from 22 to 21) quenched it, and though it didn't start oscillation when the fast gain was brought back up 1dB, I just leave it at 21.
Update:
FSS oscillated multiple times after the above was written.
The temporary cure seemed to be to lower the FSS common gain and then bring it back up. No need to change FAST gain.