~ 4:35 - 5:20 Put 'H1 EtherCAT' labels on front of h1ecatx1 and h1ecaty1 Beckhoff EtherCAT slow controls computers.
Due to a bug that cropped up with diaggui, the GDS tools have been reverted back to gds-2.16.5 which was used prior to this morning's update. This affects diag, diaggui, awggui, and foton.
late entry. Restarted DAQ to capture latest Beckhoff INI files. Didnt quite get the latest files, two channels are not connecting.
8:00–8:30 Going to End X – Sheila 9:00-12:07 Working on ACB in LVEA West Bay - Mitchell 9:00-9:40 Working at BSC 1&2 looking at CPSs – Filiberto 9:00-12:07 Working on ACB in LVEA West Bay - Mitchell 13:09- Working on ACB in LVEA West Bay – Mitchell/Apollo 13:13-15:30 Working on ITMX Chamber – Hugh 14:04-15:00 Searching for parts (cables) in LVEA - Corey 15:49 – PSL work – Sheila
Took T240s out fo blends for ITMX Isolation; just used L4C with 100mHz blend. Looked at local sensors. 0.5Hz peak only shows in Y3. Toggled Gain--no change. Zero aha!
I see there is a large offset on this channel -7000cts Y3. Hit zero button and the signal zeros, no change in the peak, darn. Cycled power of Trillium interface chassis. No change in peak.
Hey, that -7000 ct offset is back on Y3...The offset has been present essentially for as long as we've had data. Swap cables between Trillium 2 & 3, 0.5Hz peak has moved to Corner2. Oh boy, it looks like the Trillium. But, we should check the cable. Pulled cable from chamber and pins at vacuum flange look fine, reseat cable, not change, peak is still present.
Phil does continuity check on cable--there is an open conductor, Phil finds a failed solder joint at the chassis end. He is repairing now.
The attached plot shows the 0.5Hz peak with resonances, the Y3 was the only local channel with the peak. The other traces here are when we swapped the cables at the chamber and the peak stays with corner3.
OK looks like that was it. Second plot below is now with the ISI back in Isolation with the Trilliums in the blend. Same reference as above. Top graph shows the peak on Y3 and the current horizontal local channels without any peak. The bottom graph shows the vertical local T240 channels where we've never seen this. The middle graph shows the cartisian X channels of asll the ISI sensors with the Optical Levers and the SUS ISI channel. No trace of the 0.5Hz peak anywhere. Yeah!
Thanks Jeff, Keita, Phil & Richard, Sebastian!
Found issue with cable H1:SEI_BSC3_T240-3 (rack side) on pin 2. Cable wire was broken off pin. Re-terminated pin 2 and reconnected cables for corner 2 and 3 at both the rack and chamber side.
Last week, it was noticed a cable (D1000223 s/n S11004078, 216") for the TMS-EY Beam Diverter was BAD. This cable was installed in 2012 & it was noted to have possible issues at that time, so we wanted to address the cable next time we had a chance. This cable was used at a time when we didn't have our current clean/bake procedure. I've heard this might have been a cable which was baked longer or hotter than what we now consider acceptable.
Since this 25-wire cable is only for (1) Beam Diverter (uses 6-wires), we wanted to salvage this cable by switching other unused wires in the cable with the bad one. The bad/shorted wire was #23; it's paired with #11. We swapped this twisted pair with #22 & #10. Unfortunately, this didn't work. Hi-Pot test showed we had a new wire which was shorted to the Shield. Since we had four more Twisted Pairs to work with, we tried it again....and again! Sadly we kept on getting shorts with the wires.
When inspecting the wire closely, we observed tears/scuff marks on the individual wires, and exposed wire (see attached photos). Alot of this damage was near the connector (well that's all we had exposed) but the thought is when working on the connector, one slides the connector up and down the wires. This is probably causing the damage to the wires. These wires are thicker than the 22awg wire. And because of this only 17 wires fit in this connector----but it's a tight fit. In 2012, a bad cable was inspected and found to have similar damage. So the connector is abrading the insulation on the wires, and/or the over-heating weakened the wire insulation.
At this point, we stopped, and will now go with using a different cable (D1000225 s/n S1106887, 209"). This cable is different in that it is 28awg (vs D1000223's 22awg). Although not optimal, it has been approved to use this cable by Rich A/Richard M.
Andres, Sheila
After doing the PSL checks, Andres pointed out to me that the PMC power was low (1.1W reflected, 5.9 W trans). We unlocked, and saw that the total power in reflection was 12Watts, so this must be the PMC trans PD problem again. I went to have a look at the cable that Keita and company connected to the PD, (alog 9338), and saw that it was connected to the scope with a 50 Ohm input impedance. It's set to high impedance now and the readback is fine, I gues we need to be carefull about that scope, does it set itself to 50 Ohm when it is power cycled for some reason?
An ACCES Relay Card (PCIe-IIRO-8) has been added to slot 9 (Bus 1-1) of the I/O chassis for x1susex. This is to be used for automated testing of the hardware watch dog chassis.
The GDS software has been updated to gds-2.16.9. This includes fixes for the following bugs/enhancements: 299, 328, 389, 428 - Any combination of start, stop, and BW that result in an fft of 512 points fails, due to how the fftw library is used by diag. Fix by changing the way the fftw plan is generated, specifying FFTW_MEASURE instead of FFTW_ESTIMATE. 497 - Add option to foton to allow specifying a SFM name along with a filter file name. See foton man page for details on the "-s" option. 500 - Removed Kaiser Window option from diaggui, it was never implemented. 511 - Changed foton to report that no design string exists for a filter if that is the case. Previously this was reported as a different misleading problem. 519 - Allow IP broadcast for awg, tp discovery to be specified by an environment variable (LIGO_RT_BCAST) instead of assuming the broadcast address of the workstations. All these changes have been built from gds/branch/gds-2.16.9. This affects Linux and Mac OS X workstations. Existing diag or diaggui sessions should continue to work using the older software, but at some point we need to make network switch modifications that will cause the older software to stop working. Advanced warning will be given.
At BSC 1&2 looking at CPSs, this done now.
Working on ACB in West Bay.
She's heading there now.
Alexa and I are going to the ISC racks near the PSL. Also, I went to the X end for a few minutes.
work now complete
Because in this after noon I happened to be around the ISC rack with an RF source in hand, I measured and adjusted the IQ balance of the 3f demodulator which had been refurnished recently. I did the same process as was done a month ago (see alog 9100).
Here are the new settings for it:
Note that I didn't change the gains for the RF27 I and Q paths because the gain difference was smaller than 1%.
Kiwamu, Stefan, We did the PRM M3 pitch L2P decoupling tonight. We followed that same strategy as for the PR2 (alog 9584): - We paid the most attention to the highest peaks in the L2P transfer function. - We fitted L2P and P2P independently to get good initial values for a fit of the ratio. - We had a harder time with the L2P (compared to the PR2) - in particular I couldn't get the phase at 1Hz right. - The result is only Plot 1: transfer functions: - blue: measured L2P TF - green: measured P2P TF - red: L2P/P2P (from measured data) - black: fit (note that we paid more attention to the frequencies between 0.5Hz and 1Hz, because they matter most (see L2P) - Purple: fitted filter times measured P2P. Plot 2: decoupling at 0.75Hz about a factor of 6 better. Plot 3: decoupling at 0.95Hz about a factor of 4 better.
Looks like a typo in the title for this entry; should read:
PRM M3 pitch drivealign work
Arnaud, Sebastien
We've kept investigatiing on the 0.5Hz resonance issue that we've been having on ISI-ITMX (see first alog here). Reminder: we see a peak at 0.5Hz on all the sensors of the ISI when it is controlled.
After more tests, we realized that this peak appears on all the sensors only when the T240s are in the blend (see plot attached).
Plus, by looking at the T240-X signal, you can clearly see this peak at 0.5Hz. It is even more obvious when the noise floor is reduced (ISI controlled).
Thus the issue seems to come from the T240s. We'll continue the investigation tomorrow and find which T240 is bad and how to fix it.
The last plot seems to show harmonics at 1Hz, 1.5HZ(?) and 2Hz. Is this 0.5Hz sharp? If so, this could indicate a problem with the DAQ timing.
Good point Daniel. We have to double check how the other sensors behave. We'll check that tomorrow.
Exactly 0.5Hz (and its harmonics).
Still no resolutions to the problems with HAM4 ISI transfer functions. I took more DTT tf's today, and they all look a little better than the Matlab tf's. The attached plot shows the 3 vertical pods. The 3 thinner lines are the Matlab tf's (which, though not shown, have been repeated 3 times, all 3 times look pretty similar) and the 3 thicker lines (red, green and blue) are the same sensors with a DTT whitenoise tf.
I should add that the H3 GS-13 looks bad, no matter what. It's just hard to see against the general awfulness of the vertical GS-13's. The first attached image shows the DTT tf in the .5 hz to 5 hz range on the H3 GS13. There should be a taller, pointier peak at ~1hz, which is now kind of squashed. Second image is the power spectra for all GS13s, H3 doesn't look exactly the same as the others at higher frequencies, but not bad. All the other sensors look okay.
Sheila, Daniel, Stefan
I tuned up the beat note alignment this morning.
With the arm locked we have 88uW total on the COMM_A_LF detector, 42uW from the arm and 47uW from the SHG. This gives us a beatnote of 28mV pp, with the PFD RF power readback saying -35dBm.
The Comm PLL locks for a few seconds and runs out of range (due to fluctuations at the microseism frequency). One solution would be to feedback to the ETM from the green laser at the microseim frequency ( right now we only have very low frequency feedback to HEPI), this would probably be nice in the end, because the PLL would lock nicely and we need to figure out out how to do this for HIFOXY anyway. Another solution would be to engage COMM with the PLL partially locking, which does still give a useable error signal, which would be quicker to implement.
We remembered that we can just use an ezcaservo script to feed the COMM_PLL_CTRLMON signal back to offset of the the mode cleaner VCO,
ezcaservo -s 0 -g -1 -f 0.3 -r H1:ALS-C_COMM_PLL_CTRLMON H1:IMC-VCO_TUNEOFS
We then proceeded to measure the open loop transfer function of the PLL servo. The settings were:
The unity gain frequency is at 55 kHz with a phase margin of 40º.
With the same configurations as above I measured the power spectrum out of the PFD IMON while the PLL was locked.
