LVEA transitioned to LASER HAZARD

The LVEA has transitioned to  LASER HAZARD 

Work permit 7564 is complete.

This is under work permit 7565.

Ops Day Shift Summary

IO GigE1 images, new gain is 40000

I took snapshots of the IO GigE camera 1 image today with the gain set to 40000 and 45000.  Attached is a snapshot of the camera images, and cross sections from top to bottom and right to left. 

I've been running the camera at a gain of 50000, but this saturates the center of the beam.  The new camera gain is set to 40000, where no pixels saturate.

Vault Work Continues

Further investigation into the vault electronics was conducted today.  We hit the reset on the seismometer re-centering it, Robert says it looks "ok" now.

We continued work on the LEMI magnetometers.  X-LEMI is not functioning at all, Y-LEMI functions in all configurations.  It looks as if the X-LEMI itself or the cable leading to it is not working.  We adjusted the LEMI power input from +/-6V to +/-7V at the supply but this did not help the X-LEMI.  These LEMI devices are designed to run on car batteries, from +/- 12V down to +/- 6V.

LVEA transitioned to LASER SAFE

The LVEA has transitioned to  LASER SAFE 

Work permit 7562 is complete.
This is under work permit 7564.

Optical Lever Centering int the CS

Ed, Jason

• ITMY Oplev centering seems to be achieved by having to rail the translation stage responsible for pitch. This will eventually have to be addressed at a time in the future and will require some fairly invasive work/permits.
• ITMX Oplev centering went well
• PR3 Oplev centering didn't look achievable until it was determined and discovered that the Oplev LASER had been switched off. Once switched on, proper centering was rather easily achieved.
• BS Oplev  centering went well

LVEA Transition to Laser Hazard

Peter K. (WP #7562) transitioned the LVEA to laser hazard.  

SR3 RoC Voltage Monitor rails the Beckhoff ADC

Alexei, TVo

When we did the OMC scan while varying the SR3 RoC power, we noticed that the power monitor which is the digital product of an analog voltage and current monitor (found here) would have very odd behavior.  When we would request between 0.0 and 0.8 Watts, the current and voltage monitors would respond with the correct values we would expect from the simple equations (P=V^2/R=I^2*R).  However, when requesting above .8 Watts, the voltage monitor would rail and we'd get some nonsensical values.  We double checked that our drive calibration was correct in analog land, and everything turned out as we'd expect.  

We narrowed the problem down to what I think is a design issue, the voltage monitor when requesting say 0.8 Watts reads 9.7 Volts (positive-negative) at the input of the ADC.  The EL3104 modules only has a range of +/-10 Volts which means than any higher requested power will rail the ADC and gives back a nonsensical voltage reading.  I'm not sure how Beckhoff likes to throw and error if this is true. If I'm correct, we need to either switch to an ADC with a larger voltage range or an analog filter that attenuates the input signal so that we can get the full range of what we expect when energizing the heater. 

ISS 2nd loop AC coupling loop was tested with the new board, no phase margin

I measured the AC coupling loop OLTF of the ISS 2nd loop with the same setting as O2 and the phase margin was less than 3 degrees (first attachment).

I had to flip the sign of the loop, as the whitening in ERR1 which is used for this loop was changed from two inverting opamps (p=2.7k and 130kHz in V2) to just one inverting opamp (p=2.7k in V3) in D1600298. Our phase margin might have been this thin during O2 since the loop apparently works and the AC coupling is only necessary during power ramping.

Anyway, this is a bit too extreme, for the moment I'll decrease the gain by ~10dB (H1:PSL-ISS_SECONDLOOP_AC_COUPLING_SERVO_GAIN=-0.08 instead of -0.25, second attachment). If the IMC cannot take the power ramping with this setting we'll redesign the filters.

(Ignore 0.1Hz^2 Sallen-Key low pass in the AC coupling path on the medm screen, that filter is off, it's a logic error in the frontend model which I'll fix.)

(The measurement was done without light since we don't need it and since I didn't know the status of ISS 1st loop at the moment. According to Jason AOM isn't installed yet.)

09:00 Meeting Minutes

   Apollo crew removing the HAM6 doors for ASC and Squeezer work.
   SEI on standby to lock the ISI if necessary.

   Starting the week of the 21st the daily 09:00 meeting will scale back to a Monday and Thursday meeting. The time will remain at 09:00

WHAM5 ISI Corner3 FF L4C Pod Pressure Electronics Suspected of Failing---Solved

Re aLog 41668, FRS 10499

Saw the Pod Pressure at the ADC rail.  Been this way since April 12.  Investigation found unsecured (screws likely not at all engaged) field cable going into the Interface chassis.  Better seated connector and problem solved.

ETMX SUS Ground Checks Completed

Ground checks for SUS ETMX were completed this afternoon. No shorts found.

LVEA transition to LASER SAFE

The LVEA has transitioned to  LASER SAFE .

Filed under work permit #7561.

Corner Station Purge Air Compressor is ON

Turned on the Kobelco at 23:00 utc, then at 23:30 utc went into the LVEA to measure the dew point, measured at -39.4 ^oC.

The AIP for HAM5/6 were valved out and turned off.

HAM6 purge air line is connected but metal valve and butterfly valve are closed.

CP4 bake enclosure removed

Today MCE removed the CP4 bake enclosure and stored it in a connex container that Mark and Tyler cleaned out. The controls panel and heater/fan assembly are still in MY VEA and may stay there for storage. The pressure in the main volume slightly improved as a result. See plot. Current pressure = 2.40e-9 Torr.

I stripped the RGA + turbo manifold of all the heater tape, foil, etc. and made a first pass clean up. Area needs a good deep cleaning. I recommend continued use of face masks to avoid breathing in fiberglass floating in the air.

RGA scans will be logged soon.

Ops Day Shift Summary

TITLE: 05/15 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: Various maintenance activities around site, prep for HAM6 doors off tomorrow, and PEM PSL work.
LOG: See attached

SRM heater at HAM5

Thomas, Dan Brown

This morning we wheeled out the SRM heater to the north side of HAM5. The CO2 laser cannot be switched on currently until the SOP is complete, the controller for the CO2 is on Thomas' desk. The goal today was to try and align the table to the two steering mirrors and the holes in the SRM baffle. We managed to center on the ZnSe viewport and the first steering mirror. Changing pitch and yaw there we could trace the beam around the edge of the first baffle hole, we were unable to do the same on the output baffle hole. When we believed we were centered correctly the alignment beam could be clearly seen on the baffle on the HR side of the SRM, we're currently unsure whether that should be the case or not. We also do not have a good view of the beam dump from the north side which makes trying to align into it difficult. We still have some alignment work to do here before we are ready.

The north HAM5 door area is now sectioned off with screens between the squeezer table and the clean room, pictures of the area are attached. 

 

AS DC Centering and OMC ASC Loops closed, AS_C missing

Daniel, Jenne, Fil, TVo

In preparation for this weekend's work to try to do an OMC Scan measurement while varying SR3 RoC, I decided to try to make sure our new alignment of the IMC could make it down to HAM6.  I was able to get light on AS_A_DC and AS_B_DC and close the centering loops but I noticed that AS_C had no light on it which is very odd.  

All the electronics were turned back on from our grounding loop searching from April 26-27 however, the attached trend shows that something dramatic happened to that QPD segments around Apr 27 2018 15:53:41 PDT which caused the individual segments to get much noisier and the sum to drop dramatically.  I'm pretty sure we were laser safe at the time so it wasn't like the a beam falling off the diode. So I thought this might be some sort of electronics problem like a disconnected cable in the midst of the madness, but everything in the rack to the chamber feed-through seemed to be connected properly, Fil and Daniel tested the in vacuum QPD chain from the outside with a multi-meter and confirmed that there is a connected diode in chamber.

So maybe we're just not seeing light? Again, this seems strange because we see light on both AS_A and AS_B.

In general, this won't deter our work this weekend but we might want to get this figured out before we open the doors early next week or put it on the task list for the chamber.  One method we haven't tried is looking for AS_AIR and seeing if that comes out of the viewport. Also, there is a picomotor we can actuate to steer the beam onto AS_C, but I'm holding off on this unless we know what is going on.