ID |
Date |
Author |
Type |
Category |
Subject |
9779
|
Wed Apr 2 23:08:51 2014 |
Koji | Summary | ASC | New PRM ASC is running |
The new PRM ASC design
Pitch
FM1: zero at 0Hz, pole at 2000Hz, gain at 2000Hz = 2000
FM5: (boost)
zero: f: 0.5Hz q: 1 / 4Hz, q: 2 / f: 1Hz, q: 3
pole: f: 2Hz q: 3 / f: 2.7Hz, q: 2 / f: 1Hz, q: 15
FM9: (HF Roll-off)
pole: f: 40Hz q: 1/Sqrt(2) (2nd order butterworth)
Servo gain: -0.023
Yaw
FM1: zero at 0Hz, pole at 2000Hz, gain at 2000Hz = 2000
FM5: (boost)
zero: f: 0.5Hz q: 1 / 4Hz, q: 2 / f: 1.5Hz, q: 10
pole: f: 1.02Hz q: 10 / f: 3Hz, q: 5 / f: 2Hz, q: 6
FM9: (HF Roll-off)
pole: f: 40Hz q: 1/sqrt(2)
Servo gain: -0.027
The loop gains were adjusted to have the UGFs of 10Hz. The measured openloop transfer functions were compared with the model.
The transfer functions for yaw are well matched. However, the pitch ones don't. It seems that the pitch loop has extra low pass
which I can't locate. The possibility is the analog electronics of the pitch loop.
The effect of the control between 0.3Hz to 3Hz are well represented by the model. The attachment 2 shows the free running
angle fluctuation, the ones with the control engaged, and the estimated spectra. Indeed, the estimated spectra well represent
the measured angular spectra. |
Attachment 1: PRM_QPD.pdf
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Attachment 2: QPD_spe.pdf
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9778
|
Wed Apr 2 20:13:04 2014 |
Jenne | Update | PEM | More Chile EQs |
2 more earthquakes in Chile: a M6.4 and a M7.8.
We got them about 15 minutes ago (according to the BLRMS on the wall), but when I go tin, the MC was already locked, and engaging the LSC immediately got me PRMI lock (since that's the alignment state that the IFO was left in). |
9777
|
Wed Apr 2 19:50:12 2014 |
Koji | Summary | ASC | New PRM ASC is running |
As the designed ASC filters in this entry had too little phase margins (~10deg), I had to compromise the servo design.
The design was modified and tested again. This will be reported by a following entry.
Incidentally, I have adjusted the demodulation phases of REFL33/55/165 for PRMIsb so that the PRCL is eliminated from the Q signals.
REFL33 125.5 deg -> +136.5 deg
REFL55 45.0 deg -> + 25.0 deg
REFL165 -79.5 deg -> + 44.5 deg
This change of the demod phase for REFL165 was a bit surprising.
I did not check the sign, so it could be -135.5 deg. But still this is a bit change. |
9776
|
Wed Apr 2 16:34:15 2014 |
Steve | Update | VAC | Maglev controller needs service |
Quote: |
Quote: |
The date is correct on this monitor.
Last stored RGA scan data Dec 20, 2013
IFO pressure at CC1 5.8e-6 Torr
Valve configuration: Vacuum Normal, confirmable only by manual checking of position indicators and pressure gauge controllers readouts
|
The Osaka TG390MCAB maglev turbo pump's controller TC010M has passed the 40,000 hrs of operation. This triggered the " alarm" LED warning light to come on.
It is normal maintenance. Maglev TP-1 is running perfectly. Osaka will send us a loaner-controller that we can use while they do the std maintenance.
I'm thinking of ~ February to do this.
|
We just received the loaner controller that will be swapped in it tomorrow morning.
The vacuum pressure will rise somewhat during this action. |
9775
|
Wed Apr 2 09:31:22 2014 |
Steve | Update | PEM | local 3.0M earthquake |
Quote: |
Koji locked the MC, arms, and PRMI, with no troubles, after the M8.2 earthquake off the coast of Chile, that happened about 4 hours ago.
|
Atm2, Chilean 8.2M eq arrived to the 40m 16:57 in 10 minutes. Our OSEMs did not see them. Hanford got it 2 minutes later. |
Attachment 1: local3.0Meq.png
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Attachment 2: 8.2MegChili?.png
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9774
|
Wed Apr 2 01:18:30 2014 |
Jenne | Update | LSC | Attempt at PRMI+2 arms |
I was trying to lock PRMI+2 arms, but I'm losing patience with the MC losing lock. It's mostly well-behaved, but every now and again it'll lose lock, and it always seems to be just when I've gotten to a delicate part. Anyhow. I don't think anything needs fixing.
I am not able today to acquire PRMI lock with REFL 165 I&Q, nor am I able to follow Koji's prescription to transition to 165 from 55. However, I am able to transition to, or just straight-up aquire on, REFL 33 I&Q. The new ASC is awesome.
Before trying to lock with REFL165, I redid it's demod phase, by actuating on the PRM while locked on REFL 55, and minimizing the PRCL signal in the Q-phase. Old 165 phase was -83.5 degrees, new is -79.5 degrees.
I then tried the procedure of misaligning the PRM, acquiring ALS lock of both arms, finding the arm IR resonances, and moving the arms off resonance. Then I restored the PRM, and locked the PRMI on sidebands using REFL33 I&Q.
Something was a little weird and unexpected: If the arms were not far, far off resonance, there was a large MICH offset, so that AS was bright, and POP was pretty dark. If I moved the arms farther from resonance, POP would come back to the "normal" brightness, which was ~460 counts on POP110I. When POP was dark-ish, POP110I was about 150, although this number could be changed by moving the arms around. This number was not dependent on PRM alignment. Also, PRCL was not yet starting to resonate the carrier, because POPDC stayed at its low sideband-lock level of about 90 counts (vs. 2,000+ for a PRMI-only carrier lock), and POP was visually dark on the camera.
---------------------------------
While playing with PRMI + 2 ALS arms is entertaining for the evening, I don't yet have a plan for dealing with the changing CARM optical plant for IR signals situation. That's in progress in the daytime. |
9773
|
Tue Apr 1 22:03:44 2014 |
Koji | Summary | ASC | New PRM ASC is running |
[Koji Jenne]
New PRM ASC was implemented. [to be cnt'd] |
9772
|
Tue Apr 1 21:45:01 2014 |
Jenne | Summary | LSC | PRM violin notch not at correct freq? |
Koji and I have the PRMI locked right now, and we hear a very strong violin mode ringing up, at 628Hz. This is, according to Koji's elog 9634, what we expect the PRM's violin mode to be. However, the current PRM violin mode notch is really more of a bandstop filter, between 622-670Hz. At 628Hz, it has a suppression of about -20dB. If I try to increase the width of this notch by making it 612-670Hz, the PRMI won't hold lock.
We're leaving this as a daytime task for tomorrow, since we're in the middle of taking data to show that Koji's new ASC filter design (slightly tuned from his elog 9769) works well.
Edit: I have moved the PRM violin notch frequency over to 612-660 Hz, and after letting it sit for a while (while locked on PRMI), the violin mode has settled down. Interestingly, if I compare the spectrum with and without the 1st order violin mode notch, it looks like the 2nd order mode changes from 1256Hz to 1303Hz. I don't know what is going on here, but we already have notches for both of those frequencies. |
9771
|
Tue Apr 1 20:56:27 2014 |
Jenne | Update | PEM | No noticeable effect from Chile's M8.2 earthquake |
Koji locked the MC, arms, and PRMI, with no troubles, after the M8.2 earthquake off the coast of Chile, that happened about 4 hours ago. |
9770
|
Tue Apr 1 17:37:57 2014 |
Evan | Update | Computer Scripts / Programs | Comsol 4.4 upgrade |
Comsol 4.4 is now installed under /cvs/cds/caltech/apps/linux64/COMSOL44. I've left the other installations alone. I've changed the symlink on megatron so that comsol now starts Comsol 4.4.
The first time I ran comsol server, it asked me to choose a username/password combo, so I made it the same as the combo used to log on to megatron.
We should consider uninstalling some of the older Comsol versions; right now we have 4.0, 4.2, 4.3b, and 4.4 installed. |
9769
|
Mon Mar 31 23:57:22 2014 |
Koji | Summary | ASC | PRM ASC characterization / design |
A series of measurements / calculations for the PRM ASC characterization and servo design
1) Actuator characterization
The actuator responses of the PRM in pitch and yaw were measured (attachment figure 1). I believed the calibration of the oplev QPD to be
1 count/urad. The oplev servo loops were turned off at the FM inputs, and the filter banks were turned off so that the response has the open
loop transfer function except for the servo filter.
The measured transfer functions were fitted with LISO. The LISO results (c.f. the source codes) were shown in the figure. The responses also
include the 60Hz comb filter present in the input filters. The responses are well approximated by the single pendulum with f0 of 0.6-0.8 and q of 3.5 and 6.3.
From this measurement, the actuator responses of the PRM at DC are estimated to be 2.2 urad/cnt and 1.8 urad/cnt in pitch and yaw, respectively.
2) Sensor response of the POP QPD
As we already know how the actuators respond, the QPD optical gain can be characterized by measuring the actuator response of the QPD
(attachment figure 2). The QPD signals are such noisy that the response above 1Hz can't be measured with sufficient coherence. Below 1Hz,
the response is well represented by the actuator response measured with the oplev. From this measurement, the optical gains of the QPD
with respect to the PRM motion are 650 cnt/urad and 350 cnt/urad.
3) Open loop transfer function of the current ASC servo
By combining the above information with the servo setting of the servo filters, the open loop transfer functions of the PRM QPD ASC loops
were estimated (attachment figure 3). Actually the expected suppression of the fluctuation is poor. The yaw loop seems to have
too low gain, but in fact increasing gain is not so beneficial as there is no reasonable phase margin at higher frequency.
With the estimated openloop transfer functions and the measured free-running angular fluctuation, the suppressed angular spectra can be
estimated (attachment figure 4). This tells us that the suppression of the angular noise at around 3Hz is not sufficient in both pitch and yaw.
As there is no mechanical resonance in the actuator response at the frequency, intentional placement of poles and zeros in the servo filter is necessary.
4) Newly designed ASC filter
Here is the new design of the QPD ASC servo (attachment figure 5). The target upper UGF is 10Hz with the phase margin of 50 to 60deg.
The servo is AC coupled so that we still can tweak the alignment of the mirror.
As this servo is conditionally stable, at first we should close the loops with stable filter and then some boosts should be turned on.
Estimated suppressed fluctuation is shown in the attachment figure 6. We can see that the fluctuation was made well white between 0.5Hz to 10Hz.
The filter design is shown as follows:
Pitch
FM1: zero at 0Hz, pole at 2000Hz, gain at 2000Hz = 2000
FM3: (boost)
zero: f: 0.5Hz q: 1 / 4.5Hz, q: 1 / f: 1Hz, q: 3
pole: f: 2Hz q: 3 / f: 2.7Hz, q: 2 / f: 1Hz, q: 15
FM9: (HF Roll-off)
pole: f: 40Hz q: 1.7
Servo gain: -0.028
Yaw
FM1: zero at 0Hz, pole at 2000Hz, gain at 2000Hz = 2000
FM3: (boost)
zero: f: 0.7Hz q: 2 / 3Hz, q: 7 / f: 2Hz, q: 6
pole: f: 1.02Hz q: 10 / f: 4.5Hz, q: 0.8 / f: 1.5Hz, q: 10
FM9: (HF Roll-off)
pole: f: 40Hz q: 1.7
Servo gain: -0.0132
|
Attachment 1: PRM_OPLEV.pdf
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Attachment 2: PRM_QPD.pdf
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Attachment 3: OLTF_design.pdf
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Attachment 4: QPD_spe.pdf
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Attachment 5: OLTF_design2.pdf
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Attachment 6: QPD_spe2.pdf
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Attachment 7: 140328.zip
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9768
|
Mon Mar 31 21:23:30 2014 |
Gabriele | Summary | LSC | MICH sensing oddities in REFL 3F |
I'm not sure what may cause this. To back up this measurement/interpretation, I tried to take measurements of these transfer functions across different excitation frequencies via swept sine DTT, but seismic activity kept me from staying locked long enough...
|
I guess that you get an ellipse when the transfer functions to I and Q have a different phase. One mechanism could be that when driving MICH we make some residual PRCL and this couples with a different transfer function to both I and Q. However, I would expect no phase lag in the PRMI configuration, since there is no enough optical delay in the system to give significant dephasing at few hundreds Hz. This effect might come from mechanical resonances.
It is worth measuring the optical transfer functions from both PRCL and MICH to REFL signals at all frequencies, to see if we have strange features in the TFs. |
9767
|
Mon Mar 31 17:47:57 2014 |
ericq | Summary | LSC | MICH sensing oddities in REFL 3F |
Last week, while I had the PRMI locked on REFL33, I did some poking around with mirror excitation to RFPD quadrature transfer functions. I got some indication of weird things with sensing MICH with the 3F REFL signals, but it should be explored more before taken as a real thing. I just figured I would show what I saw.
With that disclaimer out of the way, here's what I did:
- Locked PRMI on PRCL:REFL33_I and MICH:REFL33_Q, as detailed in my earlier ELOG
- Created PRCL and MICH excitations at two different frequencies, notched said frequencies out of the control filters
- Took transfer functions from mirror LSC output signals to 33 I, 33 Q, 165 I, 165 Q in DTT
- For each DOF, look at the measured transfer functions only at the excitation frequency. (Assuming good coherence, which was there)
The basic idea was, some PRCL motion (for instance), has a transfer function to both the I and Q quadratures at a given PD. As the PRCL excitation sine wave goes through one cycle, the REFL signals at the excitation frequency go through some coherent cycle. Thus, the excitation traces out some trajectory in the I vs. Q plane. I believe this is analogous to the typical "radar plot" that we make for sensing matrix elements.
However, the straight line that we normally plot in the radar plots assumes a certain phase relationship between the DOF-> I and DOF->Q transfer functions that results in a straight line. Here are the trajectories I actually measured, normalized by the excitation amplitudes.
 
The plotted traces are (x,y) = (H_prcl->I * prcl, H_prcl->Q * prcl) and (x,y) = (H_mich->I * mich, H_mich->Q * mich) where H_prcl->I is the measured complex transfer function from prcl to REFL I, for instance, and prcl and mich are the excitation signals, normalized to unit amplitude.
PRCL looks like a nice straight line in both of these, and pretty well phased, but not only is MICH not very orthogonal to PRCL, there is quite a bit of ellipticity present, which means we can't fully decouple the two DOFs, even if they were nominally orthogonal.
I'm not sure what may cause this. To back up this measurement/interpretation, I tried to take measurements of these transfer functions across different excitation frequencies via swept sine DTT, but seismic activity kept me from staying locked long enough... |
9766
|
Mon Mar 31 13:26:23 2014 |
manasa | Update | LSC | LSC model modified |
I have included Yarm CESAR to the LSC model. It was just a copy paste of the Xarm CESAR. Since we are now meditating about implementing CCESAR and DCESAR, I did not run or install the model as yet. |
9765
|
Mon Mar 31 13:15:55 2014 |
manasa | Summary | LSC | Alignment update |
Quote: |
While I'm looking at the PRM ASC servo model, I tried to use the current servo filters for the ASC
as Manasa aligned the POP PDs and QPD yesterday. (BTW, I don't find any elog about it)
|
Guilty!!
POP path
The POP PD was showing only ~200 counts which was very low compared to what we recollect from earlier PRMI locks (~400 counts). Also, the POP ASC QPD was also not well-aligned.
While holding PRMI lock on REFL55, I aligned POP path to its PD (maximize POP DC counts) and QPD (centered in pitch and yaw).
X and Y green
The X green totally lost its pointing because of the misaligned PZTs from last week's power failure. This was recovered.
Y arm green alignment was also recovered. |
9764
|
Mon Mar 31 11:34:00 2014 |
manasa | Summary | IOO | MC2 moved |
Quote: |
I've also turned on the MC2 TRANS path to gather some data over the weekend on how well or bad it works. Please turn it off on Monday.
|
MC2_TRANS path in WFS servo turned OFF. |
9763
|
Mon Mar 31 08:11:00 2014 |
Steve | Update | SUS | recovery from earthquakes |
Quote: |
* EQ Southeast of LA around 45 minutes ago. Callum and I felt it.
* Koji and I came in to recover. MC suspensions had been mis-aligned. ETMs both tripped their watchdogs.
* As before, the ETMX was stuck in its cage and the UR & LR OSEMs were reading zero V.
* We moved the MC sus back to their OSEM values from 2 hours ago. Koji aligned everything else by just using his chee.
* To shake the ETMX loose, I tried a different tactic than the "Great Balls of Fire". I started giving it 20k steps through the ASCYAW filterbank (with ramping OFF). I used the green light in the X arm video to look at the swinging. Using this as a readback I pumped the OFFSET button on ASCYAW to resonantly swing up the yaw motion. I had to turn the watchdog thresh up to 2000 temporarily. After a couple minutes the ETMX was free.
* We then used the bias sliders to steer it back onto the OL center (which Q nicely lined up for us recently) and then X arm locked in green right away.
Fri Mar 28 22:38:04 2014: We've just ridden through the 5th aftershock. None of the aftershocks have tripped the watchdogs but they break the IMC lock.
|
Local earthquake activity is up. Our suspensions are holding well. ETMX and ETMY sus damping restored. |
Attachment 1: local5.1eq.png
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Attachment 2: EQ4.4-5.1-3.3-16days.png
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9762
|
Sat Mar 29 00:11:39 2014 |
Koji | Configuration | General | NTP setting on nodus |
FB: /etc/ntp.conf was updated as below such that it refers nodus and also caltech server when nodus is not available
server 192.168.113.200
server 131.215.239.14
ntpd was restarted and
diskless RT machines: they are booted from /diskless/root on fb.
Therefore /diskless/root/etc/ntp.conf was updated in the same way as above.
When the machines are rebooted, this setting will be active.
control machines:
now they are referring nodus and other external servers too. |
9761
|
Fri Mar 28 23:28:13 2014 |
Koji | Configuration | General | NTP setting on nodus |
[Koji Rana]
We are looking at NTP settings. I looked at nodus.
- xntpd is running
- We decided to start over the configuration file /etc/inet/ntp.conf
- The old configuration was moved to ntp.conf.bak
- The server configuration file was copied from ntp.server to ntp.conf
- Caltech NTP servers 131.215.239.14 and 131.215.220.22 were selected as the servers we are reffering
- Commented out the lines for "fudge " and "broadcast "
- xntpd was restarted
- sudo /etc/init.d/xntpd stop
- sudo /etc/init.d/xntpd start
- check how the daemon is running
tail -50 /var/adm/messages
Mar 28 23:00:49 nodus xntpd[27800]: [ID 702911 daemon.notice] xntpd 3-5.93e Mon Sep 20 15:47:11 PDT 1999 (1)
Mar 28 23:00:49 nodus xntpd[27800]: [ID 301315 daemon.notice] tickadj = 5, tick = 10000, tvu_maxslew = 495, est. hz = 100
Mar 28 23:00:49 nodus xntpd[27800]: [ID 798731 daemon.notice] using kernel phase-lock loop 0041
Mar 28 23:00:49 nodus last message repeated 1 time
Mar 28 23:00:49 nodus xntpd[27800]: [ID 132455 daemon.error] trusted key 0 unlikely
Mar 28 23:00:49 nodus xntpd[27800]: [ID 581490 daemon.error] 0 makes a poor request keyid
- check the syncing staus by ntpq -p
remote refid st t when poll reach delay offset disp
==============================================================================
*ntp-02.caltech. .CDMA. 1 u 37 64 377 0.56 3.010 0.08
+ntp-03.caltech. ntp1.symmetrico 2 u 36 64 377 0.52 2.727 0.12
this * means nodus is synced to ntp-02. "+" means it is stand by as a valid secondary server. "when" increases every second.
When "when" reaches "poll" the clock is synced to the server. These marks are not set at the beginning.
It was necessary to wait for sometime to get synced to the server.
- Once nodus became a synced server, the realtime systems starts syncing to nodus automatically.
controls@c1sus ~ 0$ cat /var/log/ntpd
25 Mar 01:41:00 ntpd[4443]: logging to file /var/log/ntpd
(...)
28 Mar 23:13:46 ntpd[4983]: synchronized to 192.168.113.200, stratum 2
28 Mar 23:14:25 ntpd[4983]: time reset +39.298455 s
28 Mar 23:14:25 ntpd[4983]: kernel time sync status change 2001
28 Mar 23:25:19 ntpd[4983]: synchronized to 192.168.113.200, stratum 2
controls@c1sus ~ 0$ ntpq -p
remote refid st t when poll reach delay offset jitter
==============================================================================
*nodus.martian 131.215.239.14 2 u 42 64 377 0.140 42.222 11.373
|
9760
|
Fri Mar 28 22:10:00 2014 |
rana, koji | Update | SUS | recovery from |
* EQ Southeast of LA around 45 minutes ago. Callum and I felt it.
* Koji and I came in to recover. MC suspensions had been mis-aligned. ETMs both tripped their watchdogs.
* As before, the ETMX was stuck in its cage and the UR & LR OSEMs were reading zero V.
* We moved the MC sus back to their OSEM values from 2 hours ago. Koji aligned everything else by just using his chee.
* To shake the ETMX loose, I tried a different tactic than the "Great Balls of Fire". I started giving it 20k steps through the ASCYAW filterbank (with ramping OFF). I used the green light in the X arm video to look at the swinging. Using this as a readback I pumped the OFFSET button on ASCYAW to resonantly swing up the yaw motion. I had to turn the watchdog thresh up to 2000 temporarily. After a couple minutes the ETMX was free.
* We then used the bias sliders to steer it back onto the OL center (which Q nicely lined up for us recently) and then X arm locked in green right away.
Fri Mar 28 22:38:04 2014: We've just ridden through the 5th aftershock. None of the aftershocks have tripped the watchdogs but they break the IMC lock. |
Attachment 1: Screenshot.png
|
|
9759
|
Fri Mar 28 20:23:02 2014 |
rana | Summary | IOO | MC2 moved |
I aligned MC2 suspension by 0.01 in pit and yaw to align the MC better to the PSL beam. Then I turned the WFS back on. The beams are not centered on the WFS heads.
Nic and Gabriele ought to send their SURF some example code (in April) for how to start redesigning the WFS telescopes so that we can order some optics in early June.
I've also turned on the MC2 TRANS path to gather some data over the weekend on how well or bad it works. Please turn it off on Monday. |
9758
|
Fri Mar 28 17:22:55 2014 |
Koji | Summary | LSC | PRMIsb locked with REFL165I&Q again |
While I'm looking at the PRM ASC servo model, I tried to use the current servo filters for the ASC
as Manasa aligned the POP PDs and QPD yesterday. (BTW, I don't find any elog about it)
I found no issue for locking PRMIsb with the REFL165I&Q signals if the PRM ASC is employed.
See this entry for the IFO settings.
It is just stable. The IFO is ready for the arm scanning.
=== ASC setting ===
PRCL_PITCH: FM1/3/9 x-0.004
PRCL_YAW: FM1/3/9 x-0.001
The PRM OPLEV has to be off when the PRM ASC is engaged. Actually, it turned out that we don't need OPLEV for locking. |
9757
|
Fri Mar 28 16:26:20 2014 |
steve | Update | VAC | RGA scan after power failure |
Quote: |
Out gassing plus leak rate 0.15 mTorr / hour
The pressure rose to 2.5 mTorr in 17 hours
V1 was opened at 1:56pm
VM2 opened at 2:10 so the RGA region is back to 1e-5 torr
|
|
Attachment 1: afterPowerFailure.png
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9756
|
Thu Mar 27 10:34:39 2014 |
ericq | Update | General | Recovery |
Quote: |
1. Check: ASS for X arm seems not quite doing its job. ETMX has to be moved using sliders to obtain maximum TRX and the arm alignment was seen to be drifting.
|
ETMX ASC output was turned off for whatever reason. Switched it on, ASS is fine. |
9755
|
Wed Mar 26 22:22:43 2014 |
Manasa | Update | General | Recovery |
The following that went unnoticed from yesterday were recovered today:
1. ETMX and ETMY 'misalign' scripts weren't running. Troubleshooting showed slow machines c1auxex and c1auxey weren't responding. The machines were reset.
2. PRM oplev gains were zero. Gain values were set looking back at the burt files.
3. X end PZT power supplies were turned ON and set to 100V.
4. X end doubler temperature was reset to the last optimal value on elog (36.35 deg).
Some hitches that should be looked into:
1. Check: ASS for X arm seems not quite doing its job. ETMX has to be moved using sliders to obtain maximum TRX and the arm alignment was seen to be drifting.
2. Check: Status of other slow machines and burt restore whichever needs one. |
9754
|
Wed Mar 26 21:51:42 2014 |
ericq | Summary | LSC | PRMIsb locked with REFL165I&Q again |
Incidentally, while messing around with transfer functions and sensing matrix elements this evening, I was able to sideband lock straight onto REFL33 I&Q. The settings were all identical to Koji's ELOG, with the following differences:
Input ports:
REFL33 WHTN: 30dB demod phase +125.5deg (tweaked from 135.5 to minimize MICH in I)
Input matrix:
REFL33I x +1.0 -> PRCL
REFL33Q x +3.0 -> MICH
Servo:
MICH OFS 0 / Gain 1/ Limitter ON (Oscillations occurred at 1.3)
PRCL OFS 0 / Gain -0.04 / Limitter ON
Output matrix:
MICH ITMX -1.0 / ITMY 1.0
PRCL PRM 1.0
|
9753
|
Wed Mar 26 14:54:32 2014 |
Koji | Summary | LSC | PRMIsb locked with REFL165I&Q again |
[Manasa, Eric, Koji]
PRMIsb was locked with REFL165I&Q.
- Aligned the arms with ASS. The misaligned ETMX and ETMY
- Configured PRMIsb with IFO_Configure screen
- Immediately PRMIsb was locked with REFL55I&Q
- Checked the REFL165 phase in terms of the REFL165Q vs PRCL. It was already well adjusted at -82.5deg. We tuned the phase a bit more and got -83.5deg.
- With DTT, relative gain between REFL55I and REFL165I was measured. REFL165I is about x10 higher than REFL55I and has the same sign.
- The transition of PRCL with the input matrix was just easy.
- With DTT, relative gain between REFL55Q and REFL165Q was measured. REFL165Q is about x3 higher than REFL55Q and has the same sign.
- The transition of MICH was flakey, but after careful adjustment of the PRM alignment, ~10s lock was achieved. It seemed that the PRM alignment fluctuation
was bug enough to unlock the interferometer.
- Eric went into the lab and aligned all of the oplevs except for the SRM's one.
- Now the lock with REFL55 and also with REFL165 became more robust. Less MICH offset and darker AS port.
Input ports:
REFL55 WHTN: 45dB demod phase +45.0deg
REFL165 WHTN: 45dB demod phase -83.5deg
Input matrix: for acquisition:
REFL55I x 1.0 -> PRCL
REFL55Q x 1.0 -> MICH
Input matrix: PRCL Transition:
REFL55I x 1.0 + REFL165I x 0.0 -> x0.5 + x0.0 -> x0.5 + x0.05 -> x0.3 + x0.05 -> x0.2 + x0.05 -> x0.1 + x0.05 -> x0.0 + x0.05
Input matrix: MICH Transition:
REFL55Q x 1.0 + REFL165Q x 0.0 -> x0.5 + x0.0 -> x0.5 + x0.3 -> x0.3 + x0.3 -> x0.2 + x0.3 -> x0.1 + x0.3 -> x0.0 + x0.3
Triggers:
MICH POP110I 100up/10down / FM Trig FM2/3/9 35up 2down 5sec delay
PRCL POP110I 100up/10down / FM Trig FM2/3/6/9 35up 2down 0.5sec delay
Servo:
MICH OFS 0 / Gain 1.3 / Limitter ON
PRCL OFS 0 / Gain -0.04 / Limitter ON
Output matrix:
MICH PRM -0.2625 / BS 0.5
PRCL PRM 1.0 |
9752
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Wed Mar 26 11:30:07 2014 |
Koji | Update | General | Power Failure |
Recovery work: now arms are locking as usual
- FB is failing very frequently. Everytime I see red signals in the CDS summary, I have to run "sudo ntpdate -b -s -u pool.ntp.org"
- PMC was aligned
- The main Marconi returned to initial state. Changed the frequency and amplitude to the nominal value labeled on the unit
- The SHG oven temp controllers were disabled. I visited all three units and pushed "enable" buttons.
- Y arm was immediately locked. It was aligned using ASS.
- X arm did not show any flash. I found that the scx model was not successfully burtrestored yesterday.
The setting was restored using Mar 22 snapshot.
- After a little tweak of the ETMX alignment, a decent flash was achieved. But still it could not be locked.
- Run s/LSC/LSCoffset.py. This immediately made the X arm locked.
- Checked the green alignment. The X arm green is beating with the PSL at ~100MHz but is misaligned beyond the PZT range.
The Y arm green is locked on TEM00 and is beating with the PSL at ~100MHz. |
9751
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Wed Mar 26 11:16:59 2014 |
ericq | Summary | LSC | Composite Error Signal for ARms (3) |
Extending the previous model, I've closed a rudimentary CESAR loop in simulink. Error signals with varying noise levels are combined to bring a "cavity" to lock.

There are many things that are flat out arbitrary at this point, but it qualitatively works. The main components of this model are:
- The "Plant": A pendulum with f0 = 2Hz, Q = 10
- Some white force noise, low passed at 1Hz before input to the plant.
- The Controller: A very rough servo design that is stable...
- ALS signal: Infinite range Linear signal, with a bunch of noise
- Transmission and PDH signals are computed with some compiled C code containing analytic functions (which can be a total pain to get working), have less noise than ALS
- Some logic for computing linearized PDH and SqrtInv signals
- A C code block for doing the CESAR mixing, and feeding to the servo
And it can lock! 

Right now, all of the functions and noise levels are similar to the previous simulation, and therefore don't tell us anything about anything real...
However, at this point, I can tune the parameters and noise levels to make it more like our interferometer, and thus maybe actually useful. |
9750
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Tue Mar 25 16:11:24 2014 |
Koji | Update | General | Power Failure |
As far as I know the system is running as usual. I had the IMC locked and one of the arm flashing.
But the other arm had no flash and none of the arms were locked before kunch time.
This morning Steve and I went around the lab to turn on the realtime machines.
Also we took the advantage of this opportunity to shutdown linux1 and nodus
to replace the extension cables for their AC power.
I also installed a 3TB hard disk on linux1. This was to provide a local daily copy of our
working are. But I could not make the disk recognized by the OS.
It seems that there is a "2TB" barrier that the disk bigger than 2.2TB can't be recognized
by the older machines. I'll wait for the upgrade of the machine.
Rebooting the realtime machines did not help FB to talk with them. I fixed them.
Basically what I did was:
- Stop all of the realtime codes by running rtcds kill all on c1lsc, c1ioo, c1sus, c1iscex, c1iscey
- run sudo ntpdate -b -s -u pool.ntp.org on c1lsc, c1ioo, c1sus, c1iscex, c1iscey, and fb
- restart realtime codes one by one. I checked which code makes FB unhappy. But in reality
FB was happy with all of them running.
Then slow machines except for c1vac1 and c1vac2 were burtrestored.
-------
Zach reported that svn was down. I went to the 40m wiki and searched "apache".
There is an instruction how to restart apache. |
9749
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Tue Mar 25 14:52:57 2014 |
steve | Update | VAC | vacuum is recovered |
Out gassing plus leak rate 0.15 mTorr / hour
The pressure rose to 2.5 mTorr in 17 hours
V1 was opened at 1:56pm
VM2 opened at 2:10 so the RGA region is back to 1e-5 torr
|
Attachment 1: 17hrsNoPumping.png
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9748
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Mon Mar 24 22:13:37 2014 |
steve | Update | General | Power Failure |
Quote: |
I'm checking the status from home.
P1 is 8e-4 torr
nodus did not feel the power outage (is it APS supported?)
linux1 booted automatically
c1ioo booted automatically.
c1sus, c1lsc, c1iscex, c1iscey need manual power button push.
|
9:11pm closed PSL shutter, turned Innolight 2W laser on,
turned 3 IFO air cond on,
CC1 5.1e-5 torr, V1 is closed, Maglev has failed, valve configuration is " Vacuum Normal " with V1 & VM1 closed, RGA not running, c1vac1 and c1vac2 were saved by UPS,
(Maglev is not connected to the UPS because it is running on 220V)
reset & started Maglev.........I can not open V1 without the 40mars running...........
Rossa is the only computer running in the control room,
Nodus and Linux1 was saved by UPS,
turned on IR lasers at the ends, green shutters are closed
It is safe to leave the lab as is.
|
Attachment 1: poweroutage.png
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9747
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Mon Mar 24 21:36:28 2014 |
Koji | Update | General | Power Failure |
I'm checking the status from home.
P1 is 8e-4 torr
nodus did not feel the power outage (is it APS supported?)
linux1 booted automatically
c1ioo booted automatically.
c1sus, c1lsc, c1iscex, c1iscey need manual power button push. |
9746
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Mon Mar 24 19:42:12 2014 |
Charles | Frogs | VAC | Power Failure |
The 40m experienced a building-wide power failure for ~30 seconds at ~7:38 pm today.
Thought that might be important... |
9745
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Mon Mar 24 10:41:46 2014 |
Steve | Update | VAC | RGA scan at day 50 |
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Attachment 1: pd77m50dRGA.png
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9744
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Sun Mar 23 14:20:07 2014 |
rana | HowTo | LSC | BLRMS screens |
We should make screens like this for the LSC signals, errors, ALS, etc. |
Attachment 1: blrms.png
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9743
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Fri Mar 21 14:59:44 2014 |
steve | Update | PEM | controling dust |
Please take a look at the table top with the flashlight before removing it. If it is dusty, wipe it down with dry lint free cloth in the box.
There is one box with flash light and wiper at AP, ETMY & ETMX optical tables. |
Attachment 1: IMG_0044.JPG
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9742
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Fri Mar 21 01:54:32 2014 |
ericq | Update | LSC | Some early CARM modeling |
I've been getting a simulation going with the eventual goal of simulating CESAR-type signals for CARM. So for I've only been using MIST, though I'm still thinking about what to do for a fully time domain approach. (For example, maybe a mixture of simulink and analytical equations? We'll see how painful that gets...)
Anyways, with the parameters I have for the 40m, I've set up a simulation, where I can do things like a "static" CARM scan.
(i.e. PRMI perfectly locked. Ask what different PDs see if the arms were just statically sitting at some CARM offset)

PDH signals are there in the REFL diodes. The coupled line width here looks smaller than the ~40pm number I've heard before, so I should check my parameters. (Likely culprit, I'm using nominal R and T for the arm cavities)
I've also done the slightly more sophisticated thing of looking at the transfer function from CARM motion to different PDs, at different CARM offsets. For TRX and REFLDC, these seem to match up qualitatively to some plots that Kiwamu has done for aLIGO, with frequencies shifted by the relative arm length factor of 100. (Q's left, K's right, Y-axis on mine are W/m with 1W input the IFO)
 

We can also look at the PDH diodes (revised from my initial post. Had an error in my code):
 
That's where I've gotten so far!
|
9741
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Thu Mar 20 11:16:16 2014 |
Steve | Update | General | new projector |
[ Manasa, Ericq and Steve ]
Vivitek D952HD with 186 hours installed. |
9740
|
Wed Mar 19 21:37:45 2014 |
manasa | Summary | LSC | Attempt to lock PRMIsb with REFL165I&Q |
I tried to repeat Koji's PRMI lock using REFL165I/Q. I was not able to lock PRMI stably. All I could get was momentary PRMI sb locks (few seconds) using AS55Q for MICH and REFL165Q for PRMI. I tried to transition MICH locks from AS55Q to REFL165I/Q and this did not work well; I lost even the momentary locks.
The demod phases for both AS55 and REFL165 were also very different.
Input ports:
AS55 WHTN: 21dB demod phase -78.7deg
REFL165 WHTN: 45dB demod phase -80.7deg
Input matrix:
AS55Q x1.00 MICH
REL165Q x+0.14
Triggers:
MICH POP110I 100up/10down / FM Trig FM2/3/6/7/9 35up 2down 5sec delay
PRCL POP110I 100up/10down / FM Trig FM2/3/6/9 35up 2down 0.5sec delay
Servo:
MICH OFS 0.0 / Gain -10 / Limiter ON
PRCL OFS 0 / Gain -0.023 / Limiter ON
Output matrix:
MICH ITMX -1.0 / ITMY +1.0
PRCL PRM 1.0
|
9739
|
Tue Mar 18 21:19:22 2014 |
Koji | Summary | IOO | MC spot positions checked |
MC spot sposition script was ran
/opt/rtcds/caltech/c1/scripts/ASS/MC/mcassMCdecenter
Found no notable beam position change before and after the earthquake
|
Attachment 1: MCASS.png
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9738
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Tue Mar 18 18:05:57 2014 |
Steve | Update | SUS | ETMX osem UR |
UR osem IR shield glass is pushed back. It came out of its clip holder. The magnet is free.
Atm2, UL & LL magnets centered poorly. Almost hinging on opposite sides.
UR & LR centered well. There have plenty of room to move in an earth quake. |
Attachment 1: ETMX_URcollapsing.jpg
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Attachment 2: ETMX_outoffocus.JPG
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Attachment 3: URisFREE.png
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9737
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Tue Mar 18 08:31:37 2014 |
Steve | Update | SUS | 4.4M local earthquake & its miracle |
Quote: |
It was little bit surprising to me but Rana's professorial rock'n roll excitation released its sticking on the unconfirmed thing by unconfirmed reason.
I aligned the Xarm manually and via ASS.
Now we are back in the normal state.
|
This recovery proceeder deserves a pattern
Note: IR shield glass position variations, Atm4 |
Attachment 1: miracel.png
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Attachment 2: ETMX_LR.JPG
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Attachment 3: ETMX_LR-UL.JPG
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Attachment 4: ETMX_UL-LL-S-IRshield.jpg
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9736
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Tue Mar 18 00:51:02 2014 |
Jenne | Update | SUS | 4.4M local earthquake |
I am really, really happy to hear that it was just a sticking situation. Really happy. |
9735
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Mon Mar 17 21:55:36 2014 |
Koji | Update | SUS | 4.4M local earthquake |
It was little bit surprising to me but Rana's professorial rock'n roll excitation released its sticking on the unconfirmed thing by unconfirmed reason.
I aligned the Xarm manually and via ASS.
Now we are back in the normal state. |
9734
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Mon Mar 17 20:44:42 2014 |
rana | Update | SUS | 4.4M local earthquake |
|
9733
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Mon Mar 17 20:14:34 2014 |
Koji | Summary | General | IFO recovery / confirmed ETMX in trouble |
I tried to take the photos of the magnets from outside. So far most suspicious was LL.
Otherwise, the magnets are OK.
(The SD magnet is the one with most reasonable response.)
Steve will try to take much more zoomed photo with Olympus. But the LL coil already showed some response in my observation in the morning.
   
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9732
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Mon Mar 17 12:31:58 2014 |
manasa | Update | CDS | fb timing was off |
Off again. Restarted ntp on fb. |
9731
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Mon Mar 17 12:02:55 2014 |
Koji | Summary | General | IFO recovery / confirmed ETMX in trouble |
I confirmed that we need to vent the chambers.
All of the mirrors have been aligned except for ETMX.
ETMX does not respond to the excitation by the UR and LR coils. Likely that the magnets are knocked off, or stuck in the coil.
PRM/SRM oplevs are too much off and can't be turned on. Need realignment of the beams on the QPDs.
- FB was down. FB restarted ("telnet fb 8087", then type shutdown)
- Aligned the MC mirrors.
- Aligned PRM. Look at the REFL. It was slightly mislisligned.
- AS has no beam. The Y arm was resonating with the green. So I determined that the TTs were the misaligned guys.
- Touched TT2 pitch with an increment of 0.1. Immediately the AS beam spot for ITMY was found. And the arm was resonating.
- The RM was further aligned. The bias sliders were saved and then the PRM was misaligned.
- Yarm was locked on TEM01. The ASS maximized the transmission for TEM01, and then the arm was locked on TEM00.
The ASS aligned the arm and TTs. These values were saved.
- Yarm was aligned and I can see the AS spot. So I believe the BS is still well aligned.
- Aligned the PRM to reduce the ghost beams.
- Moved the ITMX to have Michelson fringes properly.
- Also aligned the SRM.
- Now ETMX was checked. Played with the alignment biases to see if the mirror was sticking on the coils. The mirror can rock a little, but it did not come back.
- Then, checked each magnets. 0.8Hz 1000cnt signals were injected to each coils (cf. C1:SUS-PRM_**COIL_EXC) to see how the mirror could react.
The OSEM output and green spot on the ETMX cage were observed.
- Saw some response by actuating the UL, LL, SD coils.
- Saw no response from the UR and LR coils. They show the OSEM output of zero. Does this mean the magnets fell in the coils?
//Manasa// MC spot positions measured and they look alright with not much change from before the earthquake (attach) |
Attachment 1: MCspots.png
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9730
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Mon Mar 17 10:50:58 2014 |
steve | Update | safety | 2014 annual crane certification |
Quote: |
Quote: |
We had our annual safety inspection today. Our SOPs are outdated. The full list of needed correction will be posted tomorrow.
The most useful found was that the ITMX-ISCT ac power is coming from 1Y1 rack. This should actually go to 1Y2 LSC rack ?
Please test this so we do not create more ground loops.
|
Annual crane inspection is scheduled for 8-11am Monday, March 17, 2014
The control room Smart UPS has two red extension cords that has to be removed: Nodus and Linux1
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KroneCrane Fred inspected and certified the 3 40m cranes for 2014. The vertex crane crane was load tested at fully extended position. |
Attachment 1: 2014craneCert.jpg
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