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ID Date Author Type Category Subject
  9784   Thu Apr 3 18:55:10 2014 ericqSummaryLSCSome CARM related modeling

 The other day, Jenne and I were comparing my MIST simulation to her Optickle simulation for the CARM transfer functions I posted some days ago. She told me that the arms are not exactly where they should be for the whole "PRC length tuning to account for sideband reflection phase off resonant cavity" deal. 

Specifically, as in the wiki (but with newer modulation frequencies), I calculated the ideal arm length to be 37.795 m some time ago, when doing PRC length simulations, and Jenne has told me that the X arm is more like 37.6m, and Y is 37.9. So, I updated my simulations, and found the following:

This does weird things to the f2 sideband buildup on resonance in the PRFPMI configuration:

asIsPRCRes.pdf idealPRCRes.pdf

(POP is way huger than than the TR's, because the POP pd's are artificially "inside" the cavity, whereas TRX/Y is actually transmitted through an ETM)

This is not necessarily directly something to worry about, but I think the following may be. It looks like this arm length mismatch actually causes the PRCL demodulation phase in REFL 165 to change dramatically with the CARM offset. (REFL33 seems fine, though. 5 degrees causes less than a 1% effective gain change.) 

 3fPrclAnglesCarm.pdf

My simulations don't include any signal recycling yet, so I don't have anything to show if there is a similar effect for SRCL, but it wouldn't surprise me... 

 

  9783   Thu Apr 3 18:09:54 2014 ericqUpdateLSCAttempt at PRMI+2 arms

So, here's the basic: "We reduced the CARM offset and saw more TRY" plot. 

offsetTRY.pdf

 

As Jenne mentioned, we suspected that we were seeing real displacement information in the sqrtInv signals. (We had incidentally hard switched to the transmon QPDs for all of this)

Here's a 2d-histogram of the ALS CARM error signal vs. the sqrtInv CARM signal (i.e. 1/sqrt(TRX) + 1/sqrt(TRY))

 

2dhist.pdf

This is exactly the shape we expect, which is cool. You can see where we stepped the offsets, too. It looks like the signal gets into it's good linear range when ALS CARM was about -20, which is when TRY was a little under 0.1, which seems pretty early and potentially useful. 

Also, here are snapshots of what REFL11_I and sqrtInv CARM were doing in the last five seconds of time in the above plot, which was shortly before we made the offset push that broke the PRMI lock. If you look really closely, maybe you can convince yourself that there is some common information in them...? It's hard to say. In any case, there is definitely CARM pdh action happening.

pdh_trans.pdf

  9782   Thu Apr 3 17:05:52 2014 SteveUpdateVACMaglev controller swapped

Quote:

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.

 The loaner controller is swapped in. It has  520 Hz rotation speed.  This speed use to be 680 Hz with our old one.

  9781   Thu Apr 3 03:06:34 2014 JenneUpdateLSCAttempt at PRMI+2 arms

[EricQ, Jenne]

Much more success later! 

We've had the arms locked on ALS and held off resonance for more than 2 hours now.  That's good.  We've done several trials of locking the PRMI and trying to reduce the ALS CARM offset.  Once we were able to get quite close, but we never achieved zero CARM offset. 

One big finding is that when the TRX and TRY are about 0.1 in the coupled-cavity case, we start to see real length information in the 1/sqrt(trans) signals.  Q will edit this elog, or reply to it, with the data that he has collected.

  9780   Thu Apr 3 00:30:52 2014 JenneUpdateLSCAttempt at PRMI+2 arms

[EricQ, Jenne]

We started out this evening by locking the PRMI, on different REFL PDs, just to make sure that we could.  We were able to acquire lock (without having to transition) on either REFL55, REFL33 or REFL165 (I&Q phases for each).  By looking at the transfer function between REFL 55 I and REFL 165 I, I determined that the phase of REFL165 needed to be -135.5, not +44.5, so that the gains were the same sign in all REFL PDs (this is in reference to Koji's elog 9777).  The time to acquisition is much shorter with REFL55 than with the other 2 photodiodes.  I'm not sure right now why this is, but it's pretty consistent, and even more so when the arms are held off resonance.  It is also easy to acquire lock with REFL 55 and then transition to either of the 3f diodes.

PRMI settings:

MICH gain = 2.0.  FMs 4, 5 always on.  FMs 2, 3, 6, 7, 9 triggered with 35 up, 2 down.  Trigger servo on POP110I with 100 up, 10 down.

PRCL gain = -0.020.  FMs 4, 5 always on.  FMs 2, 3, 6, 9 triggered with 35 up, 2 down.  Trigger servo on POP110I with 100 up, 10 down.

PRCL ASC triggered with 50 up, 10 down.  Both pitch and yaw servos had FMs 1, 9 always on, and the FM 6 boost turned on by hand after lock acquired.  Pitch gain = -0.023, yaw gain = -0.027.

If using REFL55, PRCL = I = 1 in the input matrix, and MICH = Q = 1 in the input matrix.

If using REFL33, PRCL = I = 3 in the input matrix, and MICH = Q = 3 in the input matrix.

If using REFL165, PRCL = I = 0.15 in the input matrix, and MICH = Q = 0.1 in the input matrix.


We then moved on to trying to do PRMI + 2 arms, but have been plagued a little bit by locklosses, which may be due to the high seismic from the few large and many small Chilean aftershocks. 

Settings:  With the PRM misaligned, we acquired ALS lock in a CARM/DARM fashion.  The Xarm servo was our "darm" proxy, with +1*ALSX and +1*ALSY.  The Yarm servo was our "carm" proxy, with -1*ALSX and +1*ALSY.  The opposite signs from what you might expect is from our having placed the 2 aux laser frequencies on opposite sides of the PSL.  Our DARM (xarm) was actuating +1 on ETMX and -1 on ETMY.  Our CARM (yarm) was actuating +1 on MC2.  Then we put in a CARM offset of ~60 counts.

We then realigned the PRM, and locked the PRMI (settings as above).  It is much easier to acquire lock with REFL55 than it is with REFL33 or REFL165.  Also, when we are locking the PRMI with REFL55, the AS port is dark, and we see bright sideband resonance at the POP port, as we normally expect.  However, as with last night, when we lock the PRMI with either of the 3f PDs, we see a very bright AS port, and a dark POP port.  Tonight, putting in a MICH offset did not seem to make a significant difference.  As with last night, moving the arms farther away from resonance removed this MICH offset.  I am sure that this is not an artifact of the photodiode dark offsets not being set properly, since I rechecked those carefully. 

We have not come to any interesting conclusions about PRMI+2 arms tonight, since we have started losing the MC every few minutes (maybe seismic-related?). 

  9779   Wed Apr 2 23:08:51 2014 KojiSummaryASCNew 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.

  9778   Wed Apr 2 20:13:04 2014 JenneUpdatePEMMore 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 KojiSummaryASCNew 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 SteveUpdateVACMaglev 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 SteveUpdatePEMlocal 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.

  9774   Wed Apr 2 01:18:30 2014 JenneUpdateLSCAttempt 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 KojiSummaryASCNew PRM ASC is running

[Koji Jenne]

New PRM ASC was implemented. [to be cnt'd]

  9772   Tue Apr 1 21:45:01 2014 JenneSummaryLSCPRM 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 JenneUpdatePEMNo 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 EvanUpdateComputer Scripts / ProgramsComsol 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 KojiSummaryASCPRM 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


 

  9768   Mon Mar 31 21:23:30 2014 GabrieleSummaryLSCMICH 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 ericqSummaryLSCMICH 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.

REFL_33_traj.pdfREFL_165_traj.pdf

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 manasaUpdateLSCLSC 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 manasaSummaryLSCAlignment 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 manasaSummaryIOOMC2 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 SteveUpdateSUSrecovery 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.

  9762   Sat Mar 29 00:11:39 2014 KojiConfigurationGeneralNTP 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 KojiConfigurationGeneralNTP 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, kojiUpdateSUSrecovery 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.

  9759   Fri Mar 28 20:23:02 2014 ranaSummaryIOOMC2 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 KojiSummaryLSCPRMIsb 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 steveUpdateVACRGA 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

 

 

  9756   Thu Mar 27 10:34:39 2014 ericqUpdateGeneralRecovery

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 ManasaUpdateGeneralRecovery

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 ericqSummaryLSCPRMIsb 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 KojiSummaryLSCPRMIsb 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   Wed Mar 26 11:30:07 2014 KojiUpdateGeneralPower 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   Wed Mar 26 11:16:59 2014 ericqSummaryLSCComposite 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.  

simlink.pdf

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! 

simulatedCESARLock.pdf

 

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   Tue Mar 25 16:11:24 2014 KojiUpdateGeneralPower 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   Tue Mar 25 14:52:57 2014 steveUpdateVACvacuum 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

 

  9748   Mon Mar 24 22:13:37 2014 steveUpdateGeneralPower 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.

     

  9747   Mon Mar 24 21:36:28 2014 KojiUpdateGeneralPower 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   Mon Mar 24 19:42:12 2014 CharlesFrogsVACPower Failure

 The 40m experienced a building-wide power failure for ~30 seconds at ~7:38 pm today.

Thought that might be important...

  9745   Mon Mar 24 10:41:46 2014 SteveUpdateVACRGA scan at day 50

 

 

  9744   Sun Mar 23 14:20:07 2014 ranaHowToLSCBLRMS screens

 We should make screens like this for the LSC signals, errors, ALS, etc.

  9743   Fri Mar 21 14:59:44 2014 steveUpdatePEMcontroling 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.

  9742   Fri Mar 21 01:54:32 2014 ericqUpdateLSCSome 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)

staticCarmSweep.pdf

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)

carm2TRX.pdfCARM_TFs_TRXDC.pdf

 

carm2reflDC.pdf CARM_TFs_REFLDC.pdf

 

We can also look at the PDH diodes (revised from my initial post. Had an error in my code): 

 carm2refl11.pdfcarm2refl55.pdf

 

That's where I've gotten so far!

 

  9741   Thu Mar 20 11:16:16 2014 SteveUpdateGeneralnew projector

 

[ Manasa, Ericq and Steve ]

 Vivitek D952HD with 186 hours installed.

  9740   Wed Mar 19 21:37:45 2014 manasaSummaryLSCAttempt 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 KojiSummaryIOOMC 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

 

  9738   Tue Mar 18 18:05:57 2014 SteveUpdateSUSETMX 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.

  9737   Tue Mar 18 08:31:37 2014 SteveUpdateSUS4.4M 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

  9736   Tue Mar 18 00:51:02 2014 JenneUpdateSUS4.4M local earthquake

 

 I am really, really happy to hear that it was just a sticking situation.  Really happy. 

  9735   Mon Mar 17 21:55:36 2014 KojiUpdateSUS4.4M 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.

ELOG V3.1.3-