I changed the make-up air speed back to its nominal setting of 20% at ~19:15 UTC (12:15 PDT) on 8/7/2024.  The make-up air being on did cause the Laser Room temperature to drop by a couple degF, which in turn caused the output power of both Amp1 and Amp2 to drop by ~2W each; will monitor over the next several hours to ensure things return to normal as the enclosure returns to its normal thermal equilibrium.

Since this happened, Ryan C went into EX to reset VFD Panel, which allowed HEPI ETMX to stop tripping, but we noticed the T240s railing right after and then switching between extremes - this happened at 13:12 UTC. Screenshot below.

As of 13:31 PT (20:31) UTC, it looks like the T240 counts are coming back down.

A look at the sensors during this trip.

Was epics set point for the hepi pump beckhoff set to zero before resetting the vfd? If not, the t240 saturations are probably caused by the changing pressure in the hepi fluid while the pump servo ramps to operating pressure. Normally just resetting the pump vfd without zeroing out the set point would trip the pump, but maybe we got lucky.

Power glitch Monday 19:41:21 UTC.

Caught by MSR UPS, corner station mains_mon DQ channels for all three phases shown.

H1:HPI-PUMP_EX_CTRL_LOC_SETPT was set to zero but H1:HPI-PUMP_EX_CTRL_RMT_SETPT was still set to 70. I noticed the pressure came back on its own without me having to use the controller, that setpoint must be why. I'll make sure to zero it first next time.

The last 2 times I've run the OPLEV charge measurement for ETMX, about an hour later we've had a power glitch that takes down the VFD at the end station, 08/05 alog79455, 07/23 alog79288. Weird coincidence?

Sheila's original video is ~2sec footage of fast shutter, supposedly at 150 fps according to the file metadata.

Attached is an edited video that shows the 50ms of FS action slowed down by a factor of 10. "SRC TC" is the time elapsed since the start of (Sheila's original) video multiplied by a factor of 10, i.e. 1 sec in SRC TC is actually 100ms. This timestamp is not to be trusted at the lowest digit of sub-second (ms level in reality) because there's some frame interpolation going on due to mismatch between the standard output frame rate of 24FPS VS the source frame rate (150 slowed down to 15 FPS). Anyway, the mirror goes down lower than the closed position right after the initial thrust of the HV fast shutter motion, and even a few bounces after that, before the shutter eventually settles to the permanently closed position.

Also attached is an annotated png file of four frames ("Open", "HV thrust", "Bounce to the bottom" and "Close").

In light of recent failure of the replacement FS at LLO where the mirror broke off due to the hard stops that were set too low, and a comment by Rich (LLO alog 73584) I watched the video of the LHO unit again (see my entry above).

Though LHO video was shot from the side where we cannot see the position of the hard stop, the bobbin might be hitting the stops right after the launch even though the height of the stops looks good to my eyes. See TC~00:00:05:06. And the bobbing oscillates several times though it never hits the stops again.

Does this mean that the magnetic braking is too weak?

I converted this microphone DQ signal to an audio wav file. The microphone saturates at +/-32768 for a fraction of a second, but you can hear the echo fade away after this.

Here is the accelerometer as a wav audio:

(new file added at 13:52, orig file was created using the incorrect frequency of 16kHz, this is actually a 8kHz channel)

The ITMY Oplev (aligned at the time) didn't see this hard close, plot attached. 

Remember GV1 is closed, this makes ITMY Oplev blind, Sum on trend above is very small.