aLIGO LHO Logbook

H1 DetChar (TCS)

ansel.neunzert@LIGO.ORG - posted 12:20, Tuesday 19 December 2023 - last comment - 15:28, Tuesday 19 December 2023(74900)

7Hz comb gone in magnetometer channel after ITM HWS setting change

Camilla, Ansel

At 17:46UTC, Camilla changed ITMX and ITMY HWS to 'sem 3', which is external trigger mode. This seemed to work, and stopped the code taking photos.

It appears that the HWS-associated combs are gone in the magnetometer witness channel after this change. Pre/post 1-hour spectra attached. (All known HWS-associated combs overlaid, just to check-- the near-7Hz is the one actually present in the "pre" spectrum which corresponds to current HWS sync frequency settings.)

Images attached to this report

Comments related to this report

evan.goetz@LIGO.ORG - 13:41, Tuesday 19 December 2023 (74905)

Link

Nice work Camilla and Ansel! Let's hope this solves the problem for good.

camilla.compton@LIGO.ORG - 15:28, Tuesday 19 December 2023 (74915)

Link

At 17:38UTC I tunred on the camera/CLink and restarted the HWS EX code which had been off since 74738.

Before restarting the code I checked that I could have the camera using external trigger mode "sem 3" (see user manual P1000073), without a trigger so the camera would essentially be off or waiting. This was suggested by Ophir.

Commands:

>> serial_cmd

>> sem 3

To put back to normal mode we would use command 'sem 2', I tested setting this back and the code continued fine. I didn't need to go into the tmux session and stop/start the code, it just error-ed when the camera was in external trigger mode and took photos like normal when the camera was in standard mode.

At 17:46UTC I changed ITMX and ITMY to 'sem 3' and left them in this configuration so that they are not taking HWS data now. Now we need to write a script to read H1:GRD-ISC_LOCK_STATE_N state and adjust the camera mode to be sem 2 when we are in states < 580 (locking) and sem 3 when > 580 (locked). This is not trivial as camera computers are separate from EPICS.