Reports until 11:53, Tuesday 12 March 2019
H1 ISC (ISC)
keita.kawabe@LIGO.ORG - posted 11:53, Tuesday 12 March 2019 - last comment - 15:40, Tuesday 12 March 2019(47445)
Weak IMC-COMM VCO whistle observed, DIFF and COMM were turned off (we still have IMC-SQZ)

In the first lock of this afternoon I saw no IMC-DIFF but at least three weak IMC-COMM arches (first attached, left).

On her way to HAM6 AnaMaria also went to the ISC rack and turned off both COMM and DIFF VCO.

After that, the only clear wondering line in OMC PI channel is the second harmonics of IMC-SQZ (2nd and 3rd attachment right, triangles). It's hard to say but DCPD might be somewhat better than before turning off DIFF and COMM.

During this time SQZ guardian was in PREP_IFO_SQZ state.

Update:

VCOs were turned back on about an hour later. The time the VCOs were OFF is from about [-3914, 110]+1236395409 GPS time.

Images attached to this report
Comments related to this report
daniel.sigg@LIGO.ORG - 15:40, Tuesday 12 March 2019 (47470)

Looking back at O2, we parked the DIFF and COM VCOs at 78.786600 MHz and 78.7990 MHz, respectively, while the IMC VCO was running around 79.135 MHz.

During the last lock, we parked the DIFF and COM VCOs at 78.786600 MHz and 78.7990 MHz, respectively, while the IMC VCO was running around 78.786 MHz. The IMC VCO frequency was changed around 3/2/2019. No obvious alog.

The parking positions are unchanged, whereas the IMC VCO has moved down in frequency on top of the parking positions. This is bad! The IMC VCO needs to move ~350 kHz up in frequency.

Set the IMC-VCO_TUNEOFS to -1.7 V which puts the frequency back to 79.2 MHz.