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  40m Log, Page 121 of 335  Not logged in ELOG logo
ID Date Authorup Type Category Subject
  3718   Thu Oct 14 13:09:01 2010 Leo SingerConfigurationComputersnds2-client-devel installed on rossa

I installed nds2-client-devel on rossa using the following command:

$ sudo yum install nds2-client-devel

  3719   Thu Oct 14 13:15:14 2010 Leo SingerConfigurationComputersgit installed on rossa

I installed git on rossa using:

$ sudo yum install git

  3721   Thu Oct 14 14:52:52 2010 Leo SingerConfigurationComputersnumpy, ipython, matplotlib, python-matplotlib installed on rossa

I installed the following packages on rossa:

numpy, ipython, matplotlib, python-matplotlib

  3835   Mon Nov 1 12:38:56 2010 Leo SingerConfigurationComputerspython-sqlite installed on Allegra

I installed the Python bindings for sqlite on Allegra using

$ sudo yum install python-sqlite python-sqlite2

  3990   Mon Nov 29 18:05:17 2010 Leo SingerConfigurationComputersinstalled graphviz on Rosalba

I installed the following packages on Graphviz in order to support visualization of GStreamer pipeline graphs:

graphviz

  4642   Thu May 5 15:26:52 2011 Leo SingerConfigurationComputers'glue' installed on some control room computers

I installed 'glue' on Rossa, Allegra, and Rosalba.  This is a Python module that includes a facility for LIGO_LW XML files.  Oddly, I couldn't find the glue package on Pianosa.

  4646   Thu May 5 17:19:21 2011 Leo SingerConfigurationSUSTuning notch filters for bounce mode suspensions

I am tuning the notch filters for the bounce modes in the suspensions, starting with the ITMs and ETMs.  I'll do the MCs, the PRMs, and the SRMs next.

 

I noticed that the filter for ITMX (in the file C1SUS.txt, the module ITMX_SUSPOS, the selection BounceRoll) that the filter was composed of two bandstops (and a constant gain).  It looked like this:

 

ellip("BandStop",4,1,40,11.4,12.2)ellip("BandStop",4,1,40,16.7,17.5)gain(1.25872)

 

Valera said that one of these was for the roll mode and the other for the bounce mode.  However, looking at the spectra that Kiwamu and I made this week, I don't perceive a resonance between 11.4 and 12.2 Hz.  So, we're taking a guess that this was for a mode that has moved due to new pendulum designs.  For many of the suspensions, in the free swinging test we noticed a line around 23 Hz; we thought we might as well re-use one of these elliptical filters to avoid exciting this line.  Of course, if this line does *not* result from excitation of an uncontrolled degree of freedom, this will not help and could be detrimental.  When we talk to Valera again, we can review this decision and at that point we might decide just to take out that bandstop.

 

ITMX is done.  I'll continue tomorrow.  I've attached closed-loop spectra for before the tuning (itmx-before.pdf) and after (itmx-after.pdf).

 

(Update: the following day, I took closed loop spectra with (itmx-withbounceroll.pdf) and without (itmx-nobounceroll.pdf) the bandstops.  It looks like the bandstops made the bounce mode slightly worse, but the roll mode slightly better.)

 

 

Attachment 1: itmx-before.pdf
itmx-before.pdf
Attachment 2: itmx-before.pdf
itmx-before.pdf
Attachment 3: itmx-withbounceroll.pdf
itmx-withbounceroll.pdf
Attachment 4: timx-nobounceroll.pdf
timx-nobounceroll.pdf
  4652   Fri May 6 14:59:36 2011 Leo SingerConfigurationSUSTuning ITMY bandstop

I tuned the ITMY bandstops -- 'before' and 'after' spectra attached.  Note that the after the tuning, the bounce mode at ~16 Hz is about twice as quiet!

 

However, notice that in the 'before' plot the roll mode at about 23.5 Hz did not show up at all, whereas it is quite prominent in the 'after' plot.  I was concerned that this line could have been a result of placing the bandstop there, so I made another plot with the BounceRoll filter turned off.  Sure enough, the 23.5 Hz line is still there.  So I'm not crazy: the roll mode did start acting up at some time between my 'before' and 'after' plot, but not as a result of the tuning.

Attachment 1: itmy-before.pdf
itmy-before.pdf
Attachment 2: itmy-after.pdf
itmy-after.pdf
Attachment 3: itmy-nobounceroll.pdf
itmy-nobounceroll.pdf
  4712   Fri May 13 14:54:20 2011 Leo SingerUpdateComputersDiaggui fixed on pianosa

I fixed diaggui on pianosa.  Previously, it was not able to start because it depended on libreadline5, whereas Ubuntu distributed libreadline6.  Now pianosa has both libreadline5 and libreadline6, so diaggui works.

  4713   Fri May 13 17:20:48 2011 Leo SingerConfigurationSUSTuned bounce and roll mode of ETMY suspension

I tuned the bounce and roll mode bandstops for ETMY, although it was difficult for me to tell if there was improvement with the bandstops on relative to the bandstops off because it seemed like the bounce and roll modes were being excited intermittently.  I'll take spectra with the filters both on and off during an evening next week.

  6105   Mon Dec 12 11:34:40 2011 Leo SingerSummaryGeneralSome design parameters for a Stewart platform

At the suggestion of Rana and Koji, I have worked out some design parameters for a Stewart platform to be used as a vibration isolation device or as a platform for characterization of suspensions.  I have made some initial guesses about the following design requirements:

  • linear travel: 40 microns peak to peak (based on SOS design requirements in LIGO-T950011)
  • angular travel: 3 mrad peak to peak (based on SOS design requirements in LIGO-T950011)
  • payload mass: 5 kg (wild guess of mass of loaded SOS)
  • payload moment of inertia: 0.01 kg m^2 (wild guess)
  • bandwidth: 500 Hz (suggestion of Rana and Koji: ~kHz)

From these assumptions, I have worked out:

  • peak actuator force: 0.88 kN
  • minimum radius of top platform: 15 cm
  • minimum radius of bottom platform: 30 cm
  • minimum height: 26 cm

The combination of high force, high speed, and ~micron travel limits seems to point to piezoelectric actuators.  PI's model P-225.80 would meet the peak push-pull force requirement, but I have not yet determined if it would meet the bandwidth requirement.  Apparently, typical piezoelectric actuators can exert a greater push force than pull force; wonder if one could use an actuator with a smaller force range than the P-225.80 if the actuator is biased by compression.  (Is this what is meant by a "preloaded" actuator?) 

I have attached a PDF explaining how I worked out the actuator force and platform dimensions.  (I'll try to dice up this PDF and put the contents in the Wiki.)  I also have a plant model in MATLAB with which I have been playing around with control schemes, but I don't think that this is ready to show yet.

Here are some tasks that still remain to be done for this preliminary case study:

  • select sensing technologies: integrated linear encoders and/or strain meters, inertial sensing, optical levers, etc.
  • study joints: Koji and Rana suggest flexures; I need to propose the joint geometry and material
  • study internal modes of the platforms and actuators themselves
  • build noise budget

I'd like to ask for input principally on:

  • appropriateness of my design assumptions
  • piezo actuators currently in use in the lab

 Edit: I also added a Mathematica notebook with the inverse kinematics (mapping from platform state to leg lengths) of the platform. 

 

 

 

 

 

Attachment 1: stewart.pdf
stewart.pdf stewart.pdf stewart.pdf stewart.pdf stewart.pdf stewart.pdf stewart.pdf
Attachment 2: stewart.nb
(* Content-type: application/vnd.wolfram.mathematica *)

(*** Wolfram Notebook File ***)
(* http://www.wolfram.com/nb *)

(* CreatedBy='Mathematica 8.0' *)

(*CacheID: 234*)
(* Internal cache information:
NotebookFileLineBreakTest
... 377 more lines ...
  6163   Tue Jan 3 20:42:05 2012 Leo SingerUpdateGeneralActuators for Stewart platform

 I checked on the two single-axis shakers that are present at the 40m that Steve pointed out:

  • Brüel & Kjær type 4809, rated for 45 N peak, and
  • Brüel & Kjær type 4810, rated for 10 N peak.

Neither of these meet the force requirement of 2.04 kN peak.

  6185   Wed Jan 11 14:06:28 2012 Leo SingerHowToComputer Scripts / ProgramsHowTo for getting data from NDS off site

 This may or may not be general knowledge already, but Jamie and I added a HowTo explaining how to retrieve channel data from the frame builder via NDS, but off site on one's own computer.  See the Wiki page:

https://wiki-40m.ligo.caltech.edu/How_To/NDS

  6191   Thu Jan 12 11:08:23 2012 Leo SingerUpdatePEMFunky spectrum from STS-2

I am trying to stitch together spectra from seismometers and accelerometers to produce a ground motion spectrum from Hz to 100's of Hz.  I was able to retrieve data from two seismometers, GUR1 and STS_1, but not from any of the accelerometers.  The GUR1 spectrum is qualitatively similar to other plots that I have seen, but the STS_1 spectrum looks strange: the X axis spectrum is falling off as ~1/f, but the Y and Z spectra are pretty flat.  All three axes have a few lines that they may share in common and that they may share with GUR1.

See attached plot.

Attachment 1: spectrum.jpg
spectrum.jpg
  6192   Thu Jan 12 21:22:16 2012 Leo SingerConfigurationWIKI-40M UpdateUnable to create Wiki page

 I can't create a new page on the 40m wiki.  The page that I was trying to create is

http://blue.ligo-wa.caltech.edu:8000/40m/Stewart

I get this message when I try to save the new page:

Page could not get locked. Unexpected error (errno=13).

  6195   Fri Jan 13 00:51:40 2012 Leo SingerUpdateStewart platformFrequency-dependent requirements for Stewart platform

Below are revised design parameters for the Stewart platform based on ground motion measurements.

The goal is that the actuators should be able to exceed ground motion by a healthy factor (say, two decades in amplitude) across a range from about .1 Hz to 500 Hz.  I would like to stitch together data from at least two seismometers, an accelerometer, and (if one is available) a microphone, but since today this week I was only able to retrieve data from one of the Guralps, I will use just that for now.

The spectra below, spanning GPS times 1010311450--1010321450, show the x, y, and z axes of one of the Guralps.  Since the Guralp's sensitivity cuts off at 50 Hz or so, I assumed that the ground velocity continues to fall as f-1, but eventually flattens at acoustic frequencies.  The black line shows a very coarse, visual, piecewise linear fit to these spectra.  The corner frequencies are at 0.1, 0.4, 10, 100, and 500 Hz.  From 0.1 to 0.4 Hz, the dependence is f-2, covering the upper edge of what I presume is the microseismic peak.  From 0.4 to 10 Hz, the fit is flat at 2x10-7 m/s/sqrt(Hz).  Then, the fit is f-1 up to 100 Hz.  Finally, the fit remains flat out to 500 Hz.

ground_velocity_spectrum.png

Outside this band of interest, I chose the velocity requirement based on practical considerations.  At high frequencies, the force requirement should go to zero, so the velocity requirement should go as f--2 or faster at high frequencies.  At low frequencies, the displacement requirement should be finite, so the velocity requirement should go as f or faster.

The figure below shows the velocity spectrum extended to DC and infinite frequency using these considerations, and the derived acceleration and displacement requirements.

requirements.png

As a starting point for the design of the platform and the selection of the actuators, let's assume a payload of ~12 kg.  Let's multiply this by 1.5 as a guess for the additional mass of the top platform itself, to make 18 kg.  For the acceleration, let's take the maximum value at any frequency for the acceleration requirement, ~6x10-5 m/s2, which occurs at 500 Hz.  From my previous investigations, I know that for the optimal Stewart platform geometry the actuator force requirement is (2+sqrt(3))/(3 sqrt(2))~0.88 of the net force requirement.  Finally, let's throw in as factor of 100 so that the platform beats ground motion by a factor of 100.  Altogether, the actuator force requirement, which is always of the same order of magnitude as the force requirement, is

(12)(1.5)(6x10-5)(0.88)(100) ~ 10 mN.

Next, the torque requirement.  According to <http://www.iris.edu/hq/instrumentation_meeting/files/pdfs/rotation_iris_igel.pdf>, for a plane shear wave traveling in a medium with phase velocity c, the acceleration a(x, t) is related to the angular rate W'(x, t) through

a(x, t) / W'(x, t) = -2 c.

This implies that |W''(f)| = |a(f)| pi f / c,

where W''(f) is the amplitude spectral density of the angular acceleration and a(f) of the transverse linear acceleration.  I assume that the medium is cement, which according to Wolfram Alpha has a shear modulus of mu = 2.2 GPa and about the density of water: rho ~ 1000 kg/m3.  The shear wave speed in concrete is c = sqrt(mu / rho) ~ 1500 m/s.

The maximum of the acceleration requirement graph is, again, 6x10-5 m/s2 at 500 Hz..  According to Janeen's SolidWorks drawing, the largest principal moment of inertia of the SOS is about 0.26 kg m2.  Including the same fudge factor of (1.5)(100), the net torque requirement is

(0.26) (1.5) (6x10-5) (100) pi (500) / (1500) N m ~ 2.5x10-3 N m.

The quotient of the torque and force requirements is about 0.25 m, so, using some of my previous results, the dimensions of the platform should be as follows:

radius of top plate = 0.25 m,

radius of bottom plate = 2 * 0.25 m = 0.5 m, and

plate separation in home position = sqrt(3) * 0.25 m = 0.43 m.

 

One last thing: perhaps the static load should be taken up directly by the piezos.  If this is the case, then we might rather take the force requirement as being

(10 m/s2)(1.5)(12 kg) = 180 N.

An actuator that can exert a dynamic force of 180 N would easily meet the ground motion requirements by a huge margin.  The dimensions of the platform could also be reduced.  The alternative, I suppose, would be for each piezo to be mechanically in parallel with some sort of passive component to take up some of the static load.

  6196   Fri Jan 13 16:16:05 2012 Leo SingerUpdateStewart platformFlexure type for leg joints

I had been thinking of using this flexure for the bearings for the leg joints, but I finally realized that it was not the right type of bearing.  The joints for the Stewart platform need to be free to both yaw and pitch, but this bearing actually constrains yaw (while leaving out-of-plane translation free).

  373   Thu Mar 13 02:52:06 2008 LisaConfigurationLSCLocking with 3f
Today we have tried to use the reflected signal demodulated at 3*f1 ~ 99 MHz (REFL31) for length control.
This signal is cool because it is generated by the beating of sidebands, so it is not very sensitive to what the carrier does inside the IFO.
In particular, its gain and the demodulation phase shouldn't change much while changing the CARM offset during the locking sequence.
The idea is therefore to use REFL31_I and REFL31_Q for controlling MICH and PRCL, with the goal of making the lock acquisition sequence more robust.

We minimized hardware changes by using the 199MHz demodulation board, changing the local oscillator to 99.586317 MHz, with an amplitude of +10 dbm (the 3f signals are therefore acquired as LSC-PD6_I and LSC-PD6-Q).

We locked both the PRM and the DRM in a stable way using the REFL31_I and REFL31_Q, after tuning the demodulation phase (50) and removing their offsets.
On the other hand, we weren't able to acquire the lock in the DRM configuration directly by using the 3f signals. We needed instead to use the f signals first, and switch to the 3f signals once the lock was already acquired, otherwise ending up locking DRM at a different working point.
One explanation for that might be the fact that the beam impinging upon the 3f diode is too big compared with the diode size (only 1 mm, half of the size of the f1 diode).
For these reason, in presence of misalignments, some of the reflected light goes in high order modes, which can be partially (or all) off the diode, thereby generating multi-zero crossing in the demodulated error signal.

The next step before making the test with the whole IFO is therefore to modify the telescope in front of the 3f diode in order to reduce the beam size and repeat the tests we did tonight in DRM configuration.


P.S.: We made a test by changing the frequency of the local oscillator by a little bit and then coming back to the original value. We observed that the phase of the signal can change, so every time this frequency is moved the 3f demod phase need to be retuned.

John, Rob, Rana, Lisa
  374   Thu Mar 13 03:07:19 2008 LisaMetaphysicsEnvironmentCoolness at the 40m
My first (and hopefully not last) week at the 40m lab is ending Frown
I found this lab really cool, the people working here really cool as well, and this e-log....
this e-log is not just cool, it is FANTASTIC!!!

LISA
  8869   Thu Jul 18 10:50:54 2013 LisaUpdateLSCPRMI+Y arm ALS success!

Quote:

[Koji, Jenne, Manasa, Annalisa, Rana, Nic]

PRMI locked using 3f signals and Y arm brought to resonance using ALS

Fantastico! :-)

  8888   Mon Jul 22 06:58:17 2013 LisaSummaryloreAngel of the Y End Table?

Quote:

 Trying to take an image or movie of the ETMY Transmon cam, we got instead this attached image.

I think it is just some scattered green light, but others in the control room think that it is a message from somewhere or someone...

 It is not an angel, it is clearly a four leaf clover (also known as "quadrifoglio"). It is very rare, it brings good luck!

Attachment 1: image.jpg
image.jpg
  9050   Thu Aug 22 07:57:57 2013 LisaUpdateLSCDRMI Locked for 1+ minute!!!!!!

  Very nice!!  I was wondering, shouldn't the driving matrix be such that MICH pushes on SRM as well?

  6878   Wed Jun 27 11:27:49 2012 LizUpdate First Week Update!

This week, the other SURF students and I got acquainted with the caltech campus, LIGO 40m lab and the expectations of the SURF program.  We went to a lot of safety meetings and lectures that established a framework for the jobs we will be doing over the course of the summer.  I went on several tours of the 40m interferometer (one each with Jenne, Jamie and Steve) to get an overview of the layout and specifics of the setup.  I read parts of R. Ward and A. Parameswaran's theses and Saulson's book in order to prepare myself and gain a broader understanding of the purpose of LIGO.

I also began working in Python this week, primarily graphing PSDs of data from the C1:SUS-ETMY_SENSOR_LR, C1:SUS-ETMY_SENSOR_LL, C1:SUS-ETMY_SENSOR_UR, and C1:SUS-ETMY_SENSOR_UL channels.  I will eventually be using Python to generate the plots for the summary pages, so this is good practice.  The code that I have been working on can be found in /users/elizabeth.davison/script5.py.  Additionally, I have been going through the G1 summary pages and attempting to understand the plots available on them and the code that is available.

My plans for the upcoming week begin with modifying my code and potentially calibrating the channel data so that it is in units of length instead of counts.  I will also access the code from the G1 pages and go over it in depth, hopefully gaining insight into the structure of the website.

  6956   Wed Jul 11 09:48:24 2012 LizSummaryComputer Scripts / ProgramsUpdate/daily summary testing

I have been working on configuration of the Daily Summary webpages and have been attempting to create a "PSL health" page.  This page will display the PMC power, the temperature on the PSL table and the PSL table microphone levels.  Thus far, I have managed to make the extra PSL tab and configure the graph of the interior temperature, using channel C1:PSL-FSS_RMTEMP.

I have been attempting to make a spectrogram for one of the PMC channels, but there is an issue with the spectrogram setup, as Duncan Macleod noted in ELOG 6686:

"At the moment a package version issue means the spectrogram doesn't work, but the spectrum should. At the time of writing, to use the spectrum simple add 'plot-dataplot2'."

 

 

Because of this issue, I have also been trying to make the spectrogram plots work.  Thus far, I have fixed the issue with one of the spectrogram plots, but there are several problems with the other four that I need to address.  I have also been looking at the microphone channels and trying to make the plot for them work.  I checked which microphone was on the PSL table and plotted it in matplotlib to make sure it was working.  However, when I tried to incorporate it into the daily summary pages, the script stops at that point!  It might simply be taking an excessively long time, but I have to figure out why this is the case.

                                                 (I am using channel C1:PEM-MIC_6_IN1_DQ, if this is blatantly wrong, please let me know!!)

 

The main point of this ELOG is that I have working test-daily summary pages online!  They can be found here:

https://nodus.ligo.caltech.edu:30889/40m-summary-test/archive_daily/20120710/

Also, if anyone has more requests for what they would like to see on the finalized summary pages site, please respond to this post or email me at: endavison@umail.ucsb.edu

  6986   Wed Jul 18 10:08:01 2012 LizUpdateComputer Scripts / ProgramsWeek 5 update/progress

Over the past week, I have been focusing on the issues I brought up in my last ELOG,  6956.  I spent quite a while attempting to modify the script and create my own spectrogram function within the existing code.  I also checked out the channels on the PSL table for the PSL health page and produced a spectrogram plot of the PMC reflected, transmitted, and input powers, the PZT Voltage and the laser output power.  When I was entering these channels into the configuration script, I came across an issue with the way the python script parses this.  If there were spaces between the channel names (for example: C1:PSL-PMC_INPUT_DC, C1:PSL-PMC_RFPDDC... etc) the program would not recognize the channels.  I made some alterations to the parsing script such that all white spaces at the beginning and end of the channels were stripped and the program could find them.

 The next thing that I worked on was attempting to see if the microphone channels were actually stopping the program or just taking an extraordinarily long time.  I tried running the program with shorter time samples and that seemed to work quite well!  However, I had to leave it running overnight in order to finish.  I am sure that this difference comes from the fact that the microphone channels are fast channels.  I would like to somehow make it run more quickly, and am thinking about how best to do this.

I finally got my spectrogram function to work after quite a bit of trouble.  There were issues with mismatched data and limit sets that I discovered came from times when only a few frames (one or two) were in one block.  I added some code to  ignore small data blocks  like those and the program works very well now!  It seems like the best way to get the right limits is to let the program automatically set the limits (they are nicely log-scaled and everything) but there are some issues that produce questionable results.  I spent a while adding a colormap option to the script so that the spectrogram colors can be adjusted!  This mostly took so long because, on Monday night, some strange things were happening with the PMC that made the program fail (zeros were being output, which caused an uproar in the logarithmic data limits).  I was incredibly worried about this and thought that I had somehow messed up the script (this happened in the middle of when I was tinkering with the cmap option) so I undid all of my work!  It was only when I realized it was still going on and Masha and Jenne were talking about the PMC issues that I figured out that it was an external issue.  I then went in and set manual limits so that a blank spectrogram and redid everything.

The spectrogram is not operational and the colormap can be customized.  I need to fix the problem with the autoscaled axes (perhaps adding a lower bound?) so that the program does not crash when there is an issue.

Yesterday, I spoke with Rana about what my next step should be.  He advised me to look at ELOGs from Steve (6678) and Koji (6675) about what they wanted to see on the site.  These gave me a good map of what is needed on the site and where I will go next.

I need to find out what is going on with the weather channels and figure out how to calibrate the microphones.  I will also be making sure there are correct units on all of the plots and figure out how to take only a short section of data for the microphone channels.  I have already modified the tab template so that it is similar to Koji's ELOG idea and will be making further changes to the layout of the summary pages themselves.  I will also be working on having the right plots up consistently on the site.

 

  7012   Mon Jul 23 20:19:01 2012 LizUpdateComputer Scripts / ProgramsInput Needed (From everyone!)

The summary pages are now online (Daily Summary), and will eventually be found on the 40m Wiki page under "LOGS-Daily Summary". (Currently, the linked website is the former summary page site)

Currently, all of the IFO and Acoustic channels have placeholders (they are not showing the real data yet) and the Weather channels are not working, although the Weather Station in the interferometer room is working (I am looking into this - any theories as to why this is would be appreciated!!).

I am looking for advice on what else to include in these pages.  It would be fantastic if everyone could take a moment to look over what I have so far (especially the completed page from July 23, 2012) and give me their opinions on:

 

1.  What else you would like to see included

2.  Any specific applications to your area of work that I have overlooked

3.  What the most helpful parts of the pages are

4.  Any ways that I could make the existing pages more helpful

5.  Any other questions, comments, clarifications or suggestions

Finally, are the hourly subplots actually helpful?  It seems to me like they would be superfluous if the whole page were updating every 1-2 hours (as it theoretically eventually will).  These subplots can be seen on the July 24, 2012 page.

My email address is endavison@umail.ucsb.edu.

 Thank you!  

 

  7014   Mon Jul 23 21:17:58 2012 LizUpdatePEMWeather Station Works!

Rana and I traced the cables that ran from c1pem1 to the Weather Station monitor.  We found that the flat blue cable that is plugged into c1pem1 was not connected to the black cable from the Weather Station.  We don't know why they are unplugged, but the Weather Station had been inactive since 2010.  Rana plugged them back in (they are now connected via a sketchy connector that had its pins askew) and now the channels are outputting correct data!  Everything else seems to be in good order and now I can use the data from the Weather Station for the summary pages!

  7023   Wed Jul 25 11:22:39 2012 LizUpdateComputer Scripts / ProgramsWeek 6 update

This week, I made several modifications to the Summary page scripts, made preliminary Microphone BLRMS channels and, with Rana's help, got the Weather Station working again. 

I changed the spectrogram and spectrum options in the Summary Pages so that, given the sampling frequency (which is gathered by the program), the NFFT and overlap are calculated internally.  This is an improvement over user-entered values because it saves the time of having to know the sampling frequency for each desired plot.  In addition, I set up another .sh file that can generate summary pages for any given day.  Although this will probably not be useful in the final site, it is quite helpful now because I can go back and populate the pages.  The current summary pages file is called "c1_summary_page.sh" and the one that is set up to get a specific day is called "liz_c1_summary_page.sh".  I also made a few adjustments to the .css file for the webpage so that plots completely show up (they were getting cut off on the edges before) and are easier to see.  I also figured out that the minute and second trend options weren't working because the channel names have to be modified to CHANNEL.mean, CHANNEL.min and CHANNEL.max.  So that is all in working order now, although I'm not sure if I should just use the mean trends or look at all of them (the plots could get crowded if I choose to do this).  Another modification I made to the python summary page script was adding an option to have an image on one of the pages.  This was useful because I can now put requested MEDM screens up on the site.  The image option can be accessed if, in the configuration file, you use "image-" instead of "data-" for the first word of the section header.

I also added a link to the final summary page website on the 40 meter wiki page (my summary page are currently located in the summary-test pages, but they will be moved over once they are more finalized).  I fleshed out the graphs on the summary pages as well, and have useful plots for the OSEM and OPLEV channels.  Instead of using the STS BLRMS channels, I have decided to use the GUR BLRMS channels that Masha made.  I ELOGged about my progress and asked for any advice or recommendations a few days ago (7012) and it would still be great if everyone could take a look at what I currently have up on the website and tell me what they think!  July 22 and 23 are the most finalized pages thus far, so are probably the best to look at.

https://nodus.ligo.caltech.edu:30889/40m-summary-test/archive_daily/20120723/

 

This week, I also tried to fix the problems with the Weather Station, which had not been operational since 2010.  All of the channels on the weather station monitor seemed to be producing accurate data except the rain gauge, so I went on the roof of the Machine Shop to see if anything was blatantly wrong with it.  Other than a lot of dust and spiders, it was in working condition.  I plan on going up again to clean it because, in the manual, it is recommended that the rain collector be cleaned every one to two years...  I also cleared the "daily rain" option on the monitor and set all rain-related things to zero.  Rana and I then traced the cabled from c1pem1 to the weather station monitor, and found that thy were disconnected.  In fact, the connector was broken apart and the pins were bent.  After we reconnected them, the weather station was once again operational!  In order to prevent accidental disconnection in the future, it may be wise to secure this connection with cable ties.  It went out of order again briefly on Tuesday, but I reconnected it and now it is in much sturdier shape!

 

The most recent thing that I have been doing in relation to my project has been making BLRMS channels for the MIC channels.  With Jenne's assistance, I made the channels, compiled and ran the model on c1sus, made filters, and included the channels on the PEM MEDM screen .  I have a few modifications to make and want to .  One issue that I have come across is that the sampling rate for the PEM system is 2 kHz, and the audio frequencies range all the way up to 20 kHz.  Because of this, I am only taking BLRMS data in the 1-1000 Hz range.  This may be problematic because some of these channels may only show noise (For example, 1-3 and 3-10 Hz may be completely useless).

 

The pictures below are of the main connections in the Weather Station.  This first is the one that Rana and I connected (it is now better connected and looks like a small beige box), located near the beam-splitter chamber, and the second is the c1pem1 rack.  For more information on the subject, there is a convenient wiki page: https://wiki-40m.ligo.caltech.edu/Weather_Station

Attachment 1: P7230026.JPG
P7230026.JPG
Attachment 2: P7230031.JPG
P7230031.JPG
  7032   Wed Jul 25 17:35:44 2012 LizUpdateComputer Scripts / ProgramsSummary Pages are in the right place!

The summary pages can now be accessed from the "Daily Summary" link under LOGS on the 40 meter Wiki page.

  7063   Wed Aug 1 10:07:16 2012 LizUpdateComputer Scripts / ProgramsWeek 7 Update

Over the past week, I have continued refining the summary pages.  They are now online in their final home, and can be easily accessed from the 40 meter Wiki page!  (It can be accessed by the Daily Summary link under "LOGS").  I have one final section to add plots to (the IFO section is currently still only "dummy" plots) but the rest are showing correct data!  I have many edits to make in order for them to be more intelligible, but they are available for browsing if anyone feels so inclined.

I also spent quite a while formatting the pages so that the days are in PDT time instead of UTC time.  This process was quite time consuming and required modifications in several files, but I tracked my changes with git so they are easy to pinpoint.  I also did a bit of css editing and rewriting of a few html generation functions so that the website is more appealing.  (One example of this is that the graphs on each individual summary page are now full sized instead of a third of the size.

This week, I also worked with the BLRMS mic channels I made.  I edited the band pass and low pass filters that I had created last week and made coherence plots of the channels.  I encountered two major issues while doing this.  Firstly, the coherence of the channels decreases dramatically above 40 Hz.  I will look at this more today, but am wondering why it is the case.  If nothing could be done about this, it would render three of my channels ineffective.  The other issue is that the Nyquist frequency is at 1000 Hz, which is the upper limit of my highest frequency channel (300-1000 Hz).  I am not sure if this really affects the channel, but it looks very different from all of the other channels.  I am also wondering whether the channels below 20 Hz are useful at all, or whether they are just showing noise.

The microphone calibration has been something I have been trying to figure out for quite some time, but I recently found a value on the website that makes the EM172 microphones and has a value for their sensitivity.  I determined the transfer factor from this sensitivity as 39.8107 mV/Pa, although I am not sure if all of the mics will be consistent with this.

  7108   Tue Aug 7 18:38:50 2012 LizUpdateComputer Scripts / ProgramsDaily Summary Pages are in their final form!

Please check the summary pages out at the link below and let me know if there are any modifications I should make!  All existing pages are up to date and contain all of the pages I have.

Questions, comments, and suggestions will be appreciated! Contact me at endavison@umail.ucsb.edu

https://nodus.ligo.caltech.edu:30889/40m-summary/

  7115   Wed Aug 8 10:38:43 2012 LizUpdateComputer Scripts / ProgramsWeek 8/Summary Pages update

Over the past week, I have been working on my progress report and finalizing the summary pages.  I have a few more things to address in the pages (such as starting at 6 AM, including spectrograms where necessary and generating plots for the days more than ~a week ago) but they are mostly finalized.  I added all of the existing acoustic and seismic channels so the PEM page is up to date.  The microphone plots include information about the transfer factor that I found on their information sheet (http://www.primomic.com/).  If there are any plots that are missing or need editing, please let me know!

I also modified the c1_summary_page.sh script to run either the daily plots or current updating plots by taking in an argument in the command line.  It can be run ./c1_summary_page.sh 2012/07/27
 or ./c1_summary_page.sh now to generate the current day's pages.  (Essentially, I combined the two scripts I had been running separately.)  I have been commenting my code so it is more easily understandable and have been working on writing a file that explains how to run the code and the main alterations I made.  The most exciting thing that has taken place this week is that  the script went from taking ~6 hours to run to taking less than 5 minutes.  This was done by using minute trends for all of the channels and limiting the spectrum plot data.

The summary pages for each day now contain only the most essential plots that give a good overview of the state of the interferometer and its environment instead of every plot that is created for that day.

I am waiting for Duncan to send me some spectrogram updates he has made that downsample the timeseries data before plotting the spectrogram.  This will make it run much more quickly and introduce a more viable spectrogram option.

 

Today's Summary Pages can be accessed by the link on the wiki page or at:

https://nodus.ligo.caltech.edu:30889/40m-summary/archive_daily/20120808/

  7192   Wed Aug 15 13:23:34 2012 LizSummaryComputer Scripts / ProgramsLast Weekly Update

Over the past week I have been continuing to finalize the daily summary pages, attempting to keep the total run time under half an hour so that they can be run frequently.  I have had many hang ups with the spectrograms and am currently using second trends (with this method, the entire script takes 15 minutes to run).  I also have a backup method that takes 3 minutes of data for every 12 minutes, but could not implement any interpolation correctly.  This might be a future focus, or the summary pages could be configured to run in parallel and full data for the spectrograms can be used.  I configured Steve's tab to include one page of images and one page of plots and fixed the scripts so that it corrects for daylight savings time (at the beginning of the running, the program prints 'DST' or 'Not DST').

Right now, I am focusing on making coherence plots in a spectrogram style (similar to the matlab 'coh_carpet' function) and a spectrogram depicting Gaussianity (similar to the plots made by the RayleighMonitor).  I have also been working on my  final paper and presentation.

  7203   Thu Aug 16 13:04:36 2012 LizSummaryComputer Scripts / ProgramsDaily Summary Details

I just wrote a short description of how to run the daily summary pages and the configuration process for making changes to the site.  It can be found in /users/public_html/40m-summary and is named README.txt.  If I need to clarify anything, please let me know!  The configuration process should be relatively straightforward, so it will be easy to add plots or change them when there are changes at the 40 meter.

  12294   Tue Jul 12 20:16:15 2016 LydiaUpdateGeneralITMX dust

Looked at ITMX. Johannes and I both saw a fairly large speck of dust near the center of the HR side. We tried to take some photos but couldn't get any with good focus. 

  12299   Wed Jul 13 15:35:56 2016 LydiaUpdateGeneralVent Progress - ETMY repositioned and removed

[Lydia, Johannes]

Took photos to document the original OSEM orientation and wrote down the serial numbers for each position. We removed the OSEMs, moved the suspension to the accessible side of the table and took out the optic, which was brought to the clean room to have the magnets reglued. The ETMY chamber is now closed up with the OSEMs and clamps inside on the table, and should not need to be reopened until the magnets have been reattached. 

  12313   Tue Jul 19 16:39:29 2016 LydiaUpdateGeneralETMX magnet gluing/guiderod excess glue removed

[ericq, Lydia]

The epoxy arrived. Eric managed to remove the excess glue below the guiderod with a razor blade (see attachment 1). The magnet and dumbell that came apart were reglued successfully and passed the stregth test of picking up the magnet from the table by the dumbell, so the magnet was glued back on the optic and is setting in the gluing apparatus (see attachment 2).

We double checked the polarity against the side magnets on ETMY. Because of the gluing position strategy (a fixed distance toward the HR side from the groove location), the other side magnet appears slightly below the center of the gluing barrel, which after some discussion with Koji was determined to be ok. 

Attachment 1: P7190201.JPG
P7190201.JPG
Attachment 2: P7190203.JPG
P7190203.JPG
  12348   Thu Jul 28 16:43:01 2016 LydiaUpdateGeneralETMX aluminium standoff groove condition

 

I took some pictures with the digital microscope of the aluminum standoffs removed from ETMX. The first one had some leftover epoxy still attached, so I was able to distinguish which part of the groove was occupied by the wire. A better microscope would help (this one has a maximum magification of 80, 200 or so would be much better) but I was still able to see what looks like a second minimum inside the groove at the wire location (see Attachments 1 and 2). The bottom edge of the standoff shows the profile of the groove on the opposite side from the glue. I took several photos with different lighting angles and at different locations on the microscope stage and convinced myself that this was not just an artificial effect. I also took photos of the groove in a different place and did not see this feature (Attachment 3).

The other standoff in the same container had no visible damage to the groove or to the body of the rod. I rotated it under the mocroscope and could celarly see the 'V' shape all the way around. The smooth undanaged groove caught the light more easily and was obvious. The damaged one is scratched around much of the surface, but the undamaged standoff is very smooth. Eric, were both aluminum standoffs in the container with the extra ruby one taken off ETMX, or was one of them new? in any case, see Attachement 4 for a comparison. The believed damage is somewhat visible on the top edge of the lower standoff in the photo. 

[Edit:] Also, in the drawings it looks like the specified radius for the bottom of the groove (0.001 in) is smaller than the radius of the wire (0.00085 in). This would prevent having two clean points of contact like Steve and Gautam were describing as the goal. This is also true of drawings for the new Sapphire guiderods, though the dimensions are in metric units the specified radius of the groove bottom is smaller than the wire's diameter, but larger than its radius. Maybe this providied the initial ability for the wire to move around and carve two distinct grooves. 

Attachment 1: wire_damage_4.jpg
wire_damage_4.jpg
Attachment 2: wire_damage_zoom.jpg
wire_damage_zoom.jpg
Attachment 3: no_wire.jpg
no_wire.jpg
Attachment 4: comparison_2.jpg
comparison_2.jpg
  12363   Wed Aug 3 09:26:54 2016 LydiaUpdateSUSETMX suspended: photos

Here are the photos we took showing the magnet positions in the OSEMs, and others showing the positions of the wire and unglued standoff. These were taken before the pitch balancing adjustment Gautam described, which apparently cause UR to be a little too high. Thoe OSEMs were all inserted only until the ends of the magnets were almost inside, to lower the risk of knocking any magnets off.

 At the time of these pictures, all magnets except LL were intentionally positioned slightly above the center of the OSEM in anticipation of wire sag. The LL magnet was approximately centered in the OSEM. It was not possible to get both LL and UL the same height relative to their respective OSEMs, possibly due to a spacing error when they were glued to the optic. 

Attachment 1: Position of wire along bottom of the optic. Looks adequately centered and not kinked. 

Attachment 2: Photo showing good contact between the sandoff and the barrel of the optic. The standoff does not appear to be resting on glue from the guiderod. 

Attachment 3: Shows position of standoff and wire after rough pitch banacing. Wire is visibly resting in the groove.

Attachment 4: SD magnet location photographed through OSEM.

Attachment 5: LL magnet location photographed through OSEM.

Attachment 6: LR magnet location photographed through OSEM.

Attachment 7: UL magnet location photographed through OSEM.

Attachment 8: UR magnet location photographed through OSEM.

 

Attachment 1: wire_bottom.JPG
wire_bottom.JPG
Attachment 2: standoff_contact.JPG
standoff_contact.JPG
Attachment 3: wire_in_groove.JPG
wire_in_groove.JPG
Attachment 4: SD.JPG
SD.JPG
Attachment 5: LL.JPG
LL.JPG
Attachment 6: LR.JPG
LR.JPG
Attachment 7: UL.JPG
UL.JPG
Attachment 8: UR.JPG
UR.JPG
  12368   Wed Aug 3 16:34:59 2016 LydiaUpdateGeneralAcromag Setup | SURF2016

Actually, if the power goes off and back on, the ethernet connection comes back online after about 5 seconds, or faster if it is disconnected and reconnected. The main issue was that the cable had partially slipped out (ie both power and network connections were loose); I suggest that the final setup should use ethernet cables that have a locking tab as this one does not. 

Quote:

Lydia helped me to troubleshoot the Accromag connection problems which I was facing previously.  If power goes off/turned off manually, the ethernet cable has to be pulled out and put back again until only a non-blinking green light is observed. I was foolish enough that I did not use secure power connections. About the random symbol, a code block was not closed in the other supporting file which was being called in the main program. There are still some port errors and register errors, which I would work on later tonight.

 

  12393   Wed Aug 10 17:20:16 2016 LydiaUpdateGeneralSeismometer channel names changed

[ericq, Lydia]

We changed the seismometer channel names from, e.g. C1:PEM-SEIS_GUR1_X to C1:PEM-SEIS_EY_X.

  • GUR1 referred to the seismometer at the Y end, GUR2 referred to the seismometer at the X end, and STS1 referred to the seismometer at the vertex. These have been renamed EY, EX, and BS respectively in all channel and filter names. 
  • The models for c1pem and c1oaf were changed in Simulink. The DAQ boxes were also updated with the new names. The script which forcibly renames channels saved to disk was edited to no longer refer to the GUR1, GUR2 etc channels. Going along with what Rana suggested we decided not to change the names of the renamed channels this way when saving, so the data saved from the seismometers can be found under e.g. C1:PEM-SEIS_EY_X_OUT_DQ. 
  • The filter files generated by Foton were changed to reflect the new channel names. 
  • We compiled the changes to the models and restarted the models on the relevant machines (c1lsc for the c1oaf model and c1sus for the c1pem model). c1sus_aux was down so we manually restarted it to turn off the watchdogs as a precaution before putting too much strain on c1sus. 
  • The MEDM screens now show the correct information, relabeled with the new names under PEM-RMS. 
  • The striptool display projected on the wall now shows the appropriate C1:PEM-RMS_BS channels and has been renamed to "SeismicRainbowBS.strip" 
  • We verivied that the new channels can be accessed live and the data from the DQ channels is saved to disk. 
  • After the changes were complete, we attempted to commiting to svn (the commit also included bringing the MEDM screen files into version control.) However the svn server was taking a long time to respond, so we will try again tomorrow to commit the file changes. 
  • There are still some lefotver unused channels with name sinculding STS_2 and STS_3 that refer to seismomters we no longer use. We left these alone. 

Summary of new channel names:

C1:PEM-RMS_{BS, EX, or EY}_{X, Y, or Z} followed by the same filtering options as before, e.g. _BP_1_3_OUT

C1:PEM-SEIS_{BS, EX, or EY}_{X, Y, or Z}_{EXC, IN1, IN2, OUT, or OUT_DQ} 

C1:OAF-WIT_{BS, EX, or EY}_{X, Y, or Z}_{EXC, IN1, IN2, or OUT} 

 

  12452   Mon Aug 29 21:53:14 2016 LydiaUpdateSUSETMY bounce mode coupling

[gautam, johannes, lydia]

We decided to try some different approaches on minimizing the ETMY bounce coupling today, since the peak height in the previously attched spectrum was  higher than the previously recorded levels in 2011 for all but the LR OSEM.

  • We recoreded a coarse reference spectrum with the light door off and the HEPA filter on. 
  • We attempted to match UL, UR and LL orientation to their apparent position in photos takes before the OSEMs were initially removed. We found that every OSEM showed a stronger bounce coupling, including those that had not been moved. We repeated the spectrum a few times, damping the optic and then turning the damping back off between each data set. The effect persisted, so we decided to move them back to where they started today (the final posiitons of our earlier optimization attempt). 
  • The peaks returned to approximately their reference levels for all except LL. UL was still the worst overall, so we attempted to more finely tune its angle without success: we saw increases in the peak height in both directions again (when turned approx. 3-4 degrees). 
  • We then turned the UL OSEM by 90 degrees. (See Attachment 1). Surprisingly, the 16.4 Hz peak height was greatly reduced (by a factor of 7-9). We took another spectrum to confirm and the peak was significantly lower than the reference yet again. We decided to leave the OSEM in this configuration in order to take a finer spectrum (See Attachment 2). However, this means that while the magnet looks well centered in the OSEM, the sideways range of motion is reduced and there are no earthquake stops preventing string side to side swings, so care should be taken in the ETMY chamber. 
  • Before starting, we had discussed a possilbe mechanism for bounce coupling that could potentially be minimized by turning the OSEM so that the nominal beam direction was horizontal. This would be possible if the beam of light inside the OSEM were directed toward the front or back, i.e. if it had some component parallel to the POS axis. Then, if the component of the beam in the plane of the optic's surface is oriented vertically, the bounce mode will move the edge of the magnet's shadow in and out of the center of the beam, allowing for strong coupling (proportional to the size of the angle). Turning the OSEM by 90 degrees would eliminate this kind of coupling. 
  • It's also true that (regardless of the mechanism) minimizing bounce couling for an OSEM maximizes the side coupling. The side coupling values of the pre-vent diagonalization matrices might be useful to compare to what we see now, to find out if the minimization we do in fact increases the side coupling (if not, maybe we are not truly minimizing the bounce coupling but observing some other effect, or our measurement method is too inconsistent.) Thoughts on this are welcome. 
  • Now that this improvement has been found, we should do a more thorough investigation to see where the true optimum position is (no small steps have been taken around this new position, and the minimum could also be at some angle in between).
  • In the interest of finishing the vent, should we try to find out exactly why the optimal angles seem so different than expected, or should we just try to minimize as best we can and move on to setting up the Y arm cavity? 
Attachment 1: IMG_3051.JPG
IMG_3051.JPG
Attachment 2: 42.png
42.png
  12477   Wed Sep 7 18:00:47 2016 LydiaUpdateGeneralAcromag Progress

[Teng, Lydia]

We would like to establish a system for setting up ADC channels and integrating them into the existing EPICS framework, so that we can gradually switch over channels that are currently handled by the aging slow machines. Otherwise, we will be stuck when they eventually fail. As a preliminary test for this method, we are in the process of setting up an Acromag ADC to read the "Diagnostic" output of the PSL controller. This information will also be useful to monitor the health of the PSL. 

Today, we accomplished the following:

  • Configured the Acromag XT1221 for use on the martian netowrk. It is assigned the static IP 192.168.113.237, with hostname iocPSLmon. 
  • Connected the Acromag to a switch on the 1X6 cabinet, and set it up on a desk near the X arm door with a 24V DC power supply. 
  • Verified that the IP was reachable from a control room desktop. 
  • Modified the files from Aiden's wiki page (myiocconfig.cmd and IOCTEST.db) to reflect our setup. 
  • Attached input 0 to a DC voltage and retrieved the output over the network. 
    • Channel name: "C3:ACROMAG_INPUT0" 
    • Values are currently uncalibrated, the voltage is represented by a 16 bit signed integer
    • We changed the value of the DC input and verified that the channel output changed in the expected direction

The power supply has been turned off for the night. 

  12484   Mon Sep 12 20:15:22 2016 LydiaUpdateSUSDiagonalization in air

[Lydia, Teng]

We ran the scripts to diagonalize the damping matrices using the free swinging data from staurday night/sunday morning. The actual entries used for damping have not been changed. However, we did generate updated matrices for all the main optics (not including the mode cleaner optics, which were not free swinging over the weekend).

  • The scripts appear to be mostly working as intended, with a couple of issues:
    • The plots made by makeSUSSpectra claim to be showing spectra of the individual OSEM readings, but are actually dofs calculated using the ideal input matrix.
    • The existing parameters file (for the peak finding) was only fitting the lorentz peaks to a very narrow band of data, close to the bandwidth of the spectrum. Too narrow a band means that the initial guess must be very close, and also means there are not enough points to fit to.
      • We modified a copy of the paramters file to use a wider band (~.1 Hz) for fitting, and also use updated estimates of the mode frequencies.
      • This was largely successful, but the ITMY POS peak is very close to the SIDE peak, and POS is also stringly coupled to SIDE, so the wider bandwidth fitting can't separate the peaks. (See attachment 1)
      • A longer time series, plus more accurate initial guesses for the resonance frequencies, would allow us to fit to a smaller (~.03 Hz) band without encountering the stated issues.
      • A better way than manually examining plots to choose an initial frequency guess would be to automatically start at the overall maximum point in the spectrum between 0.4 and 1.5 Hz
  • Most of the diagonalization results seem good: "Badness" numbers of 4-6 and secondary peaks very supressed or absent on spectra plotted in dof basis (See attachment 2). ITMY, perhaps beacuse of a related issue, has phase problems with the matrix elements that result in messages like "osem/dof 2/1 is imaginary."
Attachment 1: ITMY_fit.jpg
ITMY_fit.jpg
Attachment 2: BS_diag.jpg
BS_diag.jpg
  12485   Mon Sep 12 20:19:25 2016 LydiaUpdateGeneralMC REFL beam splitter not replaced

The beam splitter that directs light into the MC REFL photodiode has not been replaced; there is still a mirror there. Gautam suggested we wait to replace it until the PSL shutter is open so the beam can be aligned. However, this must be done before going to high power.

GV addendum: What I suggested was to try and recover the arm alignment using the current low power configuration after pumpdown - since we were well aligned just before pumpdown, we should be able to recover this alignment pretty easily at low power. After locking both arms and running the dither align (also center all Oplevs), we can go ahead do the following:

  • Replace mirror in MC Refl path with 10% reflection BS (Johannes, Lydia and I confirmed that this is on the AP table earlier today). Then align the reflected beam onto the PD using the tiny mirror
  • Replace HR mirror in Transmon path at the EY table
  • Replace ND filters on Transmon QPDs at EX and EY tables
  • Repalce ND filter on Transmon CCD at EY table
  • Revert MC autolocker to the nominal version instead of the low power version we have been using during the vent
  • Turn up MC to nominal power by rotating the wave plate on the PSL table - confirm that we have nominal levels by measuring with power meter
  • Recover single arm locks, green beatnotes etc at nominal operating conditions
     
  12486   Tue Sep 13 11:00:59 2016 LydiaUpdateSUSETMY UL glitch returned

 

Quote:

For the ITMY, I squished together the cables which are in the 'Cable Interface Board' which lives in the rack. This thing takes the 64 pin IDC from the satellite module and converts it into 2 D-sub connectors to go to the PD whitening board and the coil driver board. Lets see if the ITMY OSEM glitches change character overnight.

Last night from 8:30 pm to 8:30 am PDT, ETMY UL signal was glitchy again. As of now it seems to have quieted back down, but we pushed on the cables on the board at the Y end to hopefully prevent it from coming back. After doing so it still seems to be behaving well.

  12490   Tue Sep 13 19:18:43 2016 LydiaUpdateSUSDiagonalization in air

[Lydia, Teng]

We continued to work on the diagonalization scripts today and devised a way of choosing starting parameters that seems to work much better, and is easier to use, than tuning up to 15 parameters by hand per optic.

  • As before, the spectrum for each dof is estimated by using the "ideal" input matrix.
  • The starting guess for the peak frequency for each dof is the bin which achieves the maximum value of the spectrum between 0.4 and 1.5 Hz.
  • If another dof has a higher value at that frequency, the next highest peak is used. (Sometimes, for example, the peak in PIT at the POS frequency is stronger than the real POS peak!)
  • The peak height is initially guessed to be the spectrum value at the initial frequncy guess.
  • The width paramter Q can still be read from a file, but for all the times we tried, the peaks were found successfully if Q was initially guessed to be 300, so there might be no need to do this.
  • Spectra should still be examined to make sure the results make sense, and once we look at free swinging data in vacuum, we should compare the frequency results to the wiki values.
  • Reasonably good matrix values are saved to peakFit/inMats/1157630417. We got good diagonalization results for all but ITMY (see below). The values used for damping have not been overwritten.

We still noticed phase problems with ITMY, which appear to be preventing good diagonalization (See Attachment 1). Almost every degree of freedom has a significant imaginary part in the sensing matrix. We looked at the phases of the cross spectra in DDT and saw that indeed, the OSEM signals do not have the appropriate relative phases at the peak frequencies, especially in PIT and YAW (see Attachment 2: the phase at the peak is about 30 degrees when it should be 180). These phases are different for data takes ~24 hours apart, but are still wrong. We also looked at this information for ETMY and saw the correct behavior. We temporarily moved the pitch and yaw sliders for ITMY and looked at the OSEM response on a striptool, and the signals moved in the expected way. Can anyone suggest a reason why this would be happening? Is there another stretch of data (besides this past weekend) which would be good to compare to?

 

Attachment 1: ITMY_diag.jpg
ITMY_diag.jpg
Attachment 2: 38.png
38.png
  12494   Wed Sep 14 20:05:32 2016 LydiaUpdateGeneralITMX magnets are stucked

When I restarted c1susaux yesterday, I didn't know that I needed to disable the coil outputs first. So when it came back online, it attempted to damp all the vertex area optics and ITMX got stuck frown

We should make a note in the Computer Restart Procedures wiki page indicating the importance of disabling the coils before rebooting c1susaux, c1auxex, and c1auxey. Today c1auxey was rebooted properly without incident. If the slider values etc go back to their previous values on their own, is it necessary to do a BURT restore? I tried doing one for c1susaux today and there were some errors for ASC channels, but the alignment sliders went right back to the proper place after reboot yesterday.

Quote:

I believe that the UR and LR magnets are stuck. There was no earth quake at 16:18 yesterday. Something had to kick it into this position. See 4days plot

Please advise  freeing details

 

  12495   Wed Sep 14 20:27:03 2016 LydiaUpdateSUSDiagonalization

Today the main optics were free swinging for several hours, so I attempted diagonalization in vacuum.

  • ITMY still has bad phases. I looked at the spectra for this and other optics, and it looks like the other optics have the 60Hz line notched out for all coils while ITMY only has it notched on the side coil. (Using C1:SUS-ITMY_SENSOR channels). Where is this controlled from, and could it be the source of the issue? 
    • I tried using a different coil as the "standard," with the other coils compared against it in tfestimate. Default is UL, I tried UR and LL. The phase problems were still present for ITMY, but the script was still working fine for other optics.
    • The phase difference between coils is different for different start times.
    • A short segment of the time series for ITMY shows significantly more high frequency noise than for other optics at the same time.
  • The ETMY matrix for vacuum has the wrong sign for UL coupling to pitch! The diagonalization results look OK on the graph, but the butterfly mode still has small peaks (See attachment 1). When the individual coil spectra are plotted, the angular degrees of freedom show very weak coupling for UL to pitch, and LL to yaw. We initially replaced the matrix on the MEDM screen with the one generated by the script. After realizing this, the PIT row was changed to 1 1 -1 -1 0, but the effectiveness of the damping on the locked transmission fluctuations was about the same both ways.
Attachment 1: ETMY_diag.png
ETMY_diag.png
  12497   Thu Sep 15 18:37:20 2016 LydiaUpdateSUSDiagonalization

[Teng, Lydia]

  • We fixed the 60Hz filter on ITMY. This improved the phase problems somewhat but one coil (UL) is still about 12 degrees out of phase compared to the others for all the dofs. Is there some other place where a filter coule be applied to just one coil sensor? I pressed the "Load coefficients" button for UL, so maybe that will have helped.
  • We want to interpret the coil signals to have an accurate measurement of each dof. This means what the input matrix should describe is the dependence of each dof on the OSEM signals, which is found by inverting the matrix which describes the sensitivity of each OSEM to changes in that degree of freedom.
    • We looked at the spectra of the individual coils for ITMY and ETMY (See attachment 1 & 2). The coupling between some coils and applicable resonance peaks is very weak (~0.1 times the sensitivity of the other coils).
    • However, when a certain degree of freedom, e.g. pitch, is deliberately driven using awggui, the response of the ITMY coils is clear on the StripTool and is about the same magnitude for all of the face OSEMS. So, it seems like the diagonalization script does not always succeed at measuring the relative sensitivity of the OSEMs to the degrees of freedom.
    • This may be because the fundamental swing modes experienced by the free swinging pendulum are not the same as what we measure as pitch, yaw, etc. This could be possible if the wire tension is not the same on both sides. For ITMY, the spectra imply that the funamdental frequencies are actually at some linear combinations of pitch and yaw, swinging about a diagonal axis that results in a much weaker response for some of the OSEMS. Calling these peaks pitch and yaw may be inaccurate. Certainly they do not indicate the true relative sensitivity of the coils.
    • We propose an alternate approach to measuring this sensitivity: drive one dof at a time with awggui, take a spectrum (less resolution is ok because we already know the drive frequency), and measure the sensing matrix values for that dof the same way as before, but using a spectral peak that decribes motion that we know is purely pitch. Repeat this for all 4 dofs that we can actuate on, then compile these results into a sensing matrix and take the inverse.
Attachment 1: ETMY_osemspec.png
ETMY_osemspec.png
Attachment 2: ITMY_osemspec.png
ITMY_osemspec.png
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