camilla.compton@LIGO.ORG - posted 08:26, Tuesday 12 December 2023 - last comment - 13:12, Wednesday 13 December 2023(74750)
ITM HWS Camera's Powered off at 16:15UTC, search for cause of DARM Comb
This morning at 8:15am (16:15UTC) I turned off the external power supply that powered both ITM HWS CCD cameras (Dalsa 1M60), located on the floor under the HWS table. We'll plan to check the magnetometer data to see if the 74738 comb is still present.
After we stopped HWS code and remotely turned off camera's in 74738, the DARM comb still remained. Dan, Daniel, Nutsinee expect this could be the framegrabber in the HWS computer still sending a 7Hz signal. We can troubleshoot this and how the camera's are grounded to the optics table later.
Looks like the comb is gone in the magnetometer channel. Figure 1 pre, figure 2 post.
Minor update: appending an hour-long "post" spectrum just to confirm & provide better comparison with previous 1-hour plots.
Camilla says the camera was turned on but not initialized at 10:03 Pacific / 18:03 UTC. Took a 30m spectrum starting 18:05 utc, attached. There is a strong near-1Hz comb and a strong near-57 Hz comb.
At 20:40UTC (12:40PT) we powered off both ITM computers h1hwsmsr and h1hwsmsr1. Dave has been notified. In 30 minutes we can try power cycling the cameras to see if the computers are off whether they re-initalize causing a comb.
Combs are still there with ITM computers off. Looks pretty much identical to the previous spectrum (very tiny frequency shift in the near-1Hz comb, though).
At 21:30UTC Erik unplugged the fiber connections that run from the back of the computers to the HWS cameras. Computers still off.
At 21:37UTC I power cycled the external supply to the cameras, to test if the cameras still turn on with a comb with no computer/frame grabber connection.
When the camera's restanted with the fiber link to the computers disconneted, we again saw the 1Hz and 57Hz combs, plot attached. It appears default for ITMX is 57Hz and ITMY is 1Hz. We should check if the camera software allows us to to put these to zero/ off.
For now we've replugged in the fiber connections, turned on the computers and restarted the hws code, both at 7Hz (this created some sdf diffs from the H1:TCS-ITMY_HWS_{}_POS_{X,Y} channels restarting with default values that kicked us out of observing, sorry)
Lasers still off, will turn lasers on tomorrow during commissioning to avoid sdf diffs.
Turned on both ITM SLEDs at 21:08UTC. These H1:TCS-ITM{X,Y}_HWS_SLEDSHUTDOWN channels should be added to sdf.