Nutsinee's trouble damping PI mode 27 has continued into my shift. Trouble locking PRMI after the last lock loss. Starting an initial alignment.
I have glued QTY 4 AR black glass 8.5" OD circles into the 9" ID of the pcal red anodized viewport guillotines. All 4 are with Robert now for testing.
I used the Araldite 2012 2-part epoxy which is routinely used to glue the glass fiber stock to the aluminum holder during fiber pulling production. This glue seemed a much better choice than the EP30 which is used for many in-vac applications. I followed the assembly procedure for the Araldite which the fiber lab has had good experience with, namely a ~30min 60 deg C bake on a hot plate.
| Work Permit | Date | Description | alog/status |
| 6293.html | 2016-11-01 12:28 | Activity: 1. Isolate turbo from RGA volume by closing the 1 1/2" turbo isolation valve. 2. Expose RGA to the X-end volume (with cal-gases isolated) by opening the 2 1/2" RGA isolation valve. 3. Vent turbo via turbo vent valve while monitoring X-end pressure. 4. Remove turbo and install 1 1/2" O-ring valve in its place. 5. Pump to high/rough vacuum the volume between the two series connected 1 1/2" valves. 6. Shut down and decouple pumping components | 31080 |
| 6292.html | 2016-11-01 09:05 | Install chassis in MSR and LVEA Chiller closet. We will power it up and monitor the channels for a while so no functions will be impacted. | 31090 |
| 6291.html | 2016-11-01 08:32 | Recenter BRSY. SC will be turned off. | |
| 6290.html | 2016-11-01 08:30 | Perform scheduled maintenance to scroll compressor #1, #2 @ X-End vent/purge-air supply skid. Maintenance activity will require for the compressors to run for brief periods of time. Lock-out/tag-out power to skid. | 31085 |
| 6289.html | 2016-10-31 14:32 | The guardian machine has been showing some awgstream errors. It is due a reboot (running 27 days). | 31076 |
| 6288.html | 2016-10-31 14:30 | Activity: see alog 30908, ADC chans showed an offset when h1iscex computer was power cycled but not the IO Chassis. Perform a power cycle of both computer and chassis to see if offset is cleared. | 31071 |
| 6287.html | 2016-10-31 14:27 | Add an extra PEM ADC to the h1oaf0. Shuffle the new ADC with the one used by h1ngn. h1iopoaf0 model change. DAQ restart. | 31075 |
| 6286.html | 2016-10-31 10:13 | Remove Pringles from restored DOFs list of HEPI platforms: Edit guardian parameter file for each platform. Test as needed (not really needed.) | not done |
| 6285.html | 2016-10-31 09:59 | Degas PT170 & PT180 Inficon wide range nude ion gauges, one at a time. | 31089 |
| 6284.html | 2016-10-27 13:28 | Power off the power cart/transformer along the output arm. The Op levers for HAM4 and HAM5 will need to be disconnected. The HWS power supply will also be moved. Op levers will be left powered off. | 31081 |
| 6283.html | 2016-10-27 09:10 | Adding an input offset adjustment to the AC coupling loop (FE model change). | 30928 |
| 6282.html | 2016-10-26 16:29 | First Contact the PSL-HAM1 viewport window. This viewport is a double-layered viewport with the outer surface intending to be cleaned on an in-air window. Will need LASER SAFE in LVEA, Light pipe will be removed. | 30924, 30937 |
| 6281.html | 2016-10-26 08:50 | Lift leads of thermocouple wiring at Beckhoff rack at MY station to test TC readouts at CP3 |
Per FAMIS #6870, ran & checked ISI CPS signals for the BSCs & HAMs. Both measurements are attached.
Comparing to measurement from 10/20 there are no glaring high-frequency issues. Small differences are the following:
BSC ITMx Stage1 appears to have smaller/less lines in the 40-60Hz band.
BSC ETMx Stage1 appears to have more lines in the 20-30Hz band.
Weekly site wide meeting at 3 PM local. SEI Jim W. recentered BRS at end Y Hugh was not able to complete guardian change for HEPI pringle mode DOF (WP 6286). Changes reverted. Will consult with TJ. Operators should take note of Jim's alog regarding SEI configuration. TCS Nutsinee reported in an alog that the temperature channels for both TCS laser channels are glitching. EE Working on remote access to newly installed Beckhoff safety terminals. Bad Beckhoff module replaced in corner chassis 3. CDS Tried to install an additional ADC card for PEM in the h1oaf IO chassis. Doing so prevented booting even to the BIOS screen. This glitched all of the models on the dolphin network. The ADC card was removed and the front end models restarted. No changes were made to the models on h1oaf. Testing the ADC card in the test stand reproduces the same situation. LLO range is invalid in DMT, being addressed. PSL Added polarization minimization. VAC Kyle looking for an opportunity to go to end stations. FAC Ongoing search for a water leak.
Transfer functions measured after circuit modifications made to the injection locking field box.
The gain voltage setting behaviour does not appear to be correct.
probably oscillating for gains <0V, ie., >20dB.
TITLE: 11/02 Owl Shift: 07:00-15:00 UTC (00:00-08:00 PST), all times posted in UTC
STATE of H1: Lcok Acquisition
INCOMING OPERATOR: Patrick
SHIFT SUMMARY: Bad. All locklosses tonight were caused by PI 18043Hz (Mode27). See alog31111 and comments therein. There were 6 locklosses total. I didn't keep track of all the lockloss times. None of the modes were PLL locked but only one or two casued trouble. Mode 26 also rung up but was able to damp once I get the BP filter to match the peak frequency. Not as straight forward for Mode 27.
LOG:
08:50 Lockloss
12:06 CO2X 0.2W --> 0.4W
12:09 Intent bit set
12:25 Intent bit dropped. CO2X Guardian finds lock point
12:32 Intent bit dropped. CO2X Guardian finds lock point
12:37 Lockloss
13:05 NLN. CO2X 0.2W --> 0.4W
13:39 Lockloss. Peter wants to make some measurement with the PSL so I kept the IFO down.
14:34 Peter out
Note:
Measured transfer functions after yesterday's circuit board modifications. The MEDM gain slider was increased from 0 in increments of 3.
I noticed this before, where the gain slider is miscalibrated by a factor of 2. 0dB to 40dB is mapped into +/-10V, but it looks like you only need +/-5V for the full range.
Started yesterday evening. Doesn't seems to be equally spaced.
It could be pickup through the unshielded part of the RTD cable (where it comes out of the laser), but it's strange that it started in X and Y at the same time. Can you check the FLIR cameras are turned off on the MEDM screen.
Apparently there is a "glitch" in the laser power of both X and Y TCS systems every time the Laser power meter sees a request for a power change. (see 1 day trend with additional channels to correlate with). However, this did not just start yesterday, it has been going for at least a month (see second plot of the last 3 days). I spot checked back a month and the behavior is the same. Note, there are a few extra spikes on these channels but this doesn't seem to be new behavior.
Update: I looked closer at these glitches.
Characteristic:
A single glitch spans across multiple sample points, lasted a little less than half a second. Almost everyone of these glitches lead by one smaller glitch that's roughly 1.5 second apart, followed by an even smaller glitch and immediately followed by a larger glitch.
Timeline:
I looked back several months and it seems like these glitches started to show up much more frequently on May 13th this year (started at 16:28 UTC to be precise). I looked back on the alog and didn't find any invasive work with the TCS on May12th or 13th.
I checked to make sure the line and the BP matches. Changing the phase both on the main PI medm screen and on the damping filter doesn't make a different. The PLL green light is on but Shelia mentioned that PLL is not actually locked and I don't know how to make it locked (some other modes with PLL green light indicator also have red PLL lock status). I also tried to zero the gain as Sheila suggested.
Then I found that until Maintenance morning (1 Nov 18:26 UTC to be precise) this mode has been using OMC DCPD as its input signal. It was magically switched to be using TRY QPD. I put the gain back to where it was in the matrices. We'll see how it goes.
Okay doing that somehow kill the input signal alltogether. I let through the signal from TRY QPD again but zero the damping gain.
Nevermind. Reverted it. Things became bad real fast as soon as I let through signal from TRY QPD for Mode27.
And PI broke the lock. This is the 4th lockloss caused by PI tonight.
And 5th time. The time constant is about the same as previous locklosses so I guess switching input from TRY QPD to OMC DCPD doesn't matter. In fact I couldn't get any signal from OMC DCPD so that's even worse since I have zero chance of damping it. I'm going to try the original setting again but this time alter the gain (which I have also tried).
And 6th time.
After today's changes to the PMC servo, which included increasing the loop gain, we noticed a familiar bump around 4.2kHz in DARM. Lowering the PMC gain from 16dB to 0dB made the bump smaller in DARM (see images). Given the coherence with REFL9, it seems that this is coupling through frequency noise.
We also made a small exploration around the already good PMC input beam alignment. This didn't have much impact, but it revealed that small changes in the alignment can change the input offset to the PMC servo. That is, the offset which maximizes the PMC throughput can be changed with small alignment tweaks. Using this effect, we made a 0mV input close to optimal (see second image).
Tagging PSL and ISC.
(Patrick, Gerardo)
Degassed 2 nude ion gauges in the corner station, PT170 and PT180. We did the degassing twice since the first time the degassing was terminated too early for both gauges, we sent second command before the 3 minutes were up, and it turns out that if you do send the command degassing stops. As usual pressure went up to 10-07 torr for both gauges while degassing then, trended down after.
Trends for Inficon gauges PT170 and PT180 (BSC7 and BSC8) over 60 days, compared to the signal from PT120B (BSC2) using a MKS HPS 903 inverted magnetron cold cathode.
Note that PT120B trend has been shifted up to compare slope of signals, the other trends remain unchanged.
During the windstorm yesterday, the PCal team attempted to complete end station calibrations of both ends. The calibration for EY went off without a hitch (results to come in a separate aLog). However, while setting up for the EX calibration, I dropped the working standard from the top of the PCal pylon onto the floor of the VEA. The working standard assembly ended up in 3 pieces: the integrating sphere, one spacer piece, and the PD with the second spacer piece. Minor damage was noted, mostly to the flanges of the integrating sphere and spacer pieces where the force of the fall had pulled the set screws through the thin mating flanges. I cleaned up and reassembled the working standard assembly and completed the end station calibration. Worried that some internal damage had occurred to the PD or integrating sphere, I immediately did a ratios measurement in the PCal lab. The results of this showed that the calibration of the working standard had changed by ~2% which is at the edge of our acceptable error. As a result of this accident, we are currently working to put together a new working standard assembly from PCal spares. Unfortunately this means that we will lose the calibration history of this working standard and will start fresh with a new standard. We plan to do frequent (~daily) ratios measurements of the new working standard in the PCal lab in order to establish a new calibration trend before the beginning of O2.
Opened FRS Ticket 6576 - PCal working standard damaged.
