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ID Date Author Type Category Subjectup
  238   Mon Jan 14 23:11:26 2008 tobinConfigurationGeneralfiber
John and I removed the fiber that ran from the SP table to the cleanroom. We plan to build a MZ interferometer with this fiber inserted into one of the arms, for the purpose of measuring its phase noise.
  14530   Wed Apr 10 16:58:54 2019 ranaUpdateIOOfiber MZ for NPRO freq noise measurements

Can we get some panel mount FC/APC connectors and put them on a box?   Then we could have the whole setup inside of a box that is filled with foam and sits outside the PSL hut. cheeky

  247   Thu Jan 17 20:50:55 2008 tobinUpdateGeneralfiber coupling
Sam, John, and I matched the beam from an NPRO into a fiber on the SP table today. In doing so we used our GigE camera for a physics application for perhaps the first time, viewing the transmitted mode from the fiber during initial alignment. (I used my laptop running Windows and a 100 megabit switch.)
  10677   Thu Nov 6 10:18:12 2014 SteveUpdateGeneralfiber insulation in cable tray

Quote:

[Steve, Diego, Manasa]

Since the beatnotes have disappeared, I am taking this as a chance to put the FOL setup together hoping it might help us find them.

Two 70m long fibers now run along the length of the Y arm and reach the PSL table.

The fibers are running through armaflex insulating tubes on the cable racks. The excess length ~6m sits in its spool on the top of the PSL table enclosure.

Both the fibers were tested OK using the fiber fault locator. We had to remove the coupled end of the fiber from the mount and put it back in the process. So there is only 8mW of end laser power at the PSL table after this activity as opposed to ~13mW.  This will be recovered with some alignment tweaking.

After the activity I found that the ETMY wouldn't damp. I traced the problem to the ETMY SUS model not running in c1iscey. Restarting the models in c1iscey solved the problem.

 

 AP Armaflex  tube 7/8" ID X 1" wall insulation for the long fiber in wall mounted cable trays installed yesterday.

The 6 ft long sections are not glued. Cable tied into the tray pressed against one an other, so they are air tight. This will allow us adding more fibers later.

 Atm2: Fiber PSL ends  protection added on Friday.

 

Attachment 1: APT07810.jpg
APT07810.jpg
Attachment 2: fromYend.jpg
fromYend.jpg
  8813   Tue Jul 9 17:03:06 2013 SteveUpdateGreen Lockingfiber layed for Y arm

Alex, Gautam and Steve,

Single mode fiber 50m long is layed out into cable tray that is attached to the beam tube of the Y arm.

It goes from ETMY to PSL enclosure. It is protected at both ends with " clear- pvc, slit corrugated loom tubing " 1.5" ID

The fiber is not protected between 1Y1 and 1Y4

Attachment 1: fromETMYtowardPSL.jpg
fromETMYtowardPSL.jpg
Attachment 2: fibreETMYtoPSL50m.jpg
fibreETMYtoPSL50m.jpg
Attachment 3: PSLfiberfromETMY.jpg
PSLfiberfromETMY.jpg
  8578   Wed May 15 08:29:28 2013 SteveConfigurationRF Systemfiber protection at splitter box area

 I positioned the fiber loaded protecting tubing and anchored them so they can do their job.

However, the area needs a good clean up.

 

Attachment 1: fiberprotect.jpg
fiberprotect.jpg
  564   Wed Jun 25 11:01:45 2008 MashaUpdateAuxiliary lockingfiber stabilization
For the first week, I have been learning about fiber noise cancellation, auxiliary locking techniques, and other relevant helpful topics in more detail. I am now working on a setup (more detail in previous entry) to measure phase noise introduced by 25m(?) fiber, and then will proceed to try to cancel the noise.
  4852   Wed Jun 22 01:59:43 2011 SonaliUpdateGreen Lockingfibre-coupling of the IR beam

 What I did today.

1. Collimation of a beam.

  • I then practiced collimation of a 700 nm laser (output) beam after being coupled through a fibre.
  • I put together the set-up as shown in the attached picture where I used ....... to couple 650nm light into the PM.... fiber.
  • I kept shifting the focus of the output beam to an appreciable distance till it was approximately collimated.

2. Coupling of the IR light at the ETMY table to a fibre.

  • The fibre coupler was put in place to couple light into the fiber.
  • I put in the mirrors as planned to direct the IR beam exiting the doubling crystal towards the fiber coupler (input).
  • The mirrors were aligned such that the beam falls on the input lens of the coupler.
  • The far-end of the fibre originally would have gone to to PSL table but it has been put on this table to study the power of the IR beam transmitted through this set-up.  The output end of the fiber has been connected to another fiber optic coupler to collimate the exiting beam.
  • The picture of the current status attached.
Attachment 1: ETMY_june_21.jpg
ETMY_june_21.jpg
Attachment 2: collimation_700nm_21_june.JPG
collimation_700nm_21_june.JPG
  7185   Wed Aug 15 00:52:17 2012 DenUpdateWienerFilteringfilter calculation

A Matlab script to calculate Wiener filter coefficients and convert fir to iir is ready. Input is a file with zero mean witness and desired signals, output is a Foton zpk command to specify iir filter.

The plot shows comparison of offline fir , iir and online iir filtering. Spectrum below 4 Hz is still oscillating due to acoustic coupling, this is not a filtering effect. At 1 Hz actuator is badly compensated, more work should be done. Other then that online and offline filtering are the same.

wiener.png

  7052   Mon Jul 30 16:05:36 2012 DenUpdatedigital noisefilter checker

 We decided to write a script that will check online filters for digital noise. One method can be implemented using the following algorithm:

  • calculate filter output using single precision
  • calculate filter output using double precision and assume that it is precise
  • find digital noise at the output of the filter when single precision is used
  • extrapolate the result to the double precision filter dividing by 2D-S ~ 107, D - number of bits used in double precision mantissa, S - in single precision

Restriction: Single precision filter internal variables must be checked for overflows.

I applied this method to filtering a 1 Hz sine wave with a notch filter. Precise output should also be a 1 Hz wave => at other frequencies we see noise => digital noise spectrum should coincide with filter output. The plot shows the method worked out for this example.

iir_psd_notch.png

Using this method I estimated digital noise of butter("LowPass", 2, 0.001) applied to white noise. Sampling frequency was 16 kHz. 

iir_psd_lp.png iir_time_lp.png

  7085   Sat Aug 4 17:32:31 2012 DenUpdatedigital noisefilter checker

The script estimates digital noise produces by online filters. First version of Matlab files and complied c files are in scripts/digital_noise directory.

Algorithm for 1 filter bank (max number of filters = 10):

  1.        extract sos - representation from Foton file for each filter (Matlab)
  2.        download data from corresponding DQ channel using NDS (Matlab)
  3.        find filters that are switched on (Matlab)
  4.        filter signal using Df2 and BQF with single and double precision (C)
  5.        estimate digital filter noise (Matlab)
  6.        calculate power spectral density and plot the result (Matlab)

More details on (2)

Often DQ channels have reduced sampling rate. In this case the script will upsample data adding zeros.

AI filter is not applied. But in the end only the frequency range (0, DQ RATE / 2) is analyzed.

More details on (3):

This is done by reading C1:MODEL-BANK_NAME_SW1R and C1:MODEL-BANK_NAME_SW2R channels.
 
_SW1R channel value is the sum of the following numbers:
  • input switch ON / OFF => 4 / 0
  • filters 1 - 6 ON /OFF
    • 1 => 48 / 0
    • 2 => 192 / 0
    • 3 => 768 / 0
    • 4 => 3072 / 0
    • 5 => 12288 / 0
    • 6 => 49152 / 0
    • If a switch is ON but there is no corresponding filter (one green and one red line under the switch) then the switch value is divided by 3

_SW2R channel value is the sum of the following numbers:

  • decimation switch ON / OFF => 512 / 0
  • output switch ON / OFF => 1024 / 0
  • filters 7 - 10 ON /OFF
    • 7 => 3 / 0
    • 8 => 12 / 0
    • 9 => 48 / 0
    • 10 => 192 / 0
    • If a switch is ON but there is no corresponding filter (one green and one red line under the switch) then the switch value is divided by 3

Note: as for now Matlab script assumes that input, output and decimation filters are switched ON and there are no turned ON filter switches that do not correspond to any filters

More details on (5)

Digital noise using double precision is estimated by extrapolation of digital noise with single precision. The last is calculated by subtracting outputs of the filters with single and double precision. Then this noise is multiplied by 3 * 10-7.

This extrapolation number was achieved by printf tests of the number 0.123456789012345678 with single and double precision on C. Using type 'float' variables 10 significant numbers show up, using type 'double' - 17.

I also did 'calibration tests' to achieve extrapolation number - signal was filters with an aggresive low-pass filter. At high frequencies filter output spectrum is flat => digital noise amplitude must be the same. The plot shows GUR1_X channel filtered with low-pass chebyshev type 1 filter.

gur1x.png

However, extrapolation number is not the same for all cases. In the following example of analyzing BS_SUSPOS filter bank using extrapolation 3 * 10-7 we get noise that is slightly overestimated. In some other examples we need to take a larger number. But in average, I think, this is a good approximation.

C1SUS_BS_SUSPOS.png

To avoid extrapolation problem we can use long double precision (~19 digits). I was able to do this with gcc compiler. However, in mex compiler using long double in filter calculations, I do not get any better precision then using double precision. I'll think more about it.

  6137   Mon Dec 19 17:17:02 2011 DenUpdateAdaptive Filteringfilter tap dependence

Online filter diverges. I did offline simulations with current c-code. Offline filter also diverges, even in the simplest case 

witness = randn(1e6, 1); target = witness + 0.01*randn(1e6, 1);

I tried to create a new implementation of FXLMS algorithm as a c code. Then with this c code I did offline filtering with MCL and GUR signals and compared the error signals depending on the length of the filter.

OfflineAF.png

One can see the code at the svn

adaptOnline - start here and choose algorithm

adaptive_filtering - Matlab implementation of AF

current_version.c - current version of the Filter (Matt's)

fxlms_filter.c - new version of the FXLMS filter

oaf.c - agent between Matlab and C (edited Matt's file)

Data samples can be found at nodus /users/den/wiener_filtering/data

  480   Thu May 15 14:39:33 2008 CarynSummaryPEMfiltering mode cleaner with mic
Tried filtering for mode cleaner data(C1:IOO-MC_L) using a siso-firwiener filter and microphone data(C1:PEM-AS_MIC) for noise input. The noise reduction in mode cleaner data using the microphone-filter is comparable to the noise reduction when an accelerometer(C1:PEM-ACC_MC1_X) filter is used. See attached graphs.
Attachment 1: MC_L_with_PEM-AS_MIC_filter.pdf
MC_L_with_PEM-AS_MIC_filter.pdf
Attachment 2: MC_L_with_PEM-ACC_MC1_X_filter.pdf
MC_L_with_PEM-ACC_MC1_X_filter.pdf
  494   Fri May 23 21:21:52 2008 CarynSummaryGeneralfiltering mode cleaner with wiener filter
I tried filtering some saved MC_L data (from Mon May19 4:30pm) with multiple MISO filters of different orders, with various sampling rates, at different times. Plotted the max rms error (where error is signal minus signal-estimate). 2min of data (around Mon May19 4:30pm) were used to calculate each filter. And each filter was applied to data at later times to see how well it performed as time progressed. Plots are attached. There appears to have been a disturbance during the 3rd hour. Rana pointed out perhaps it would be better to use data from the evening rather than during the day.
Attachment 1: error_vs_N_for_different_times_64Hz.pdf
error_vs_N_for_different_times_64Hz.pdf
Attachment 2: error_vs_N_for_different_times_128Hz.pdf
error_vs_N_for_different_times_128Hz.pdf
Attachment 3: error_vs_N_for_different_times_256Hz.pdf
error_vs_N_for_different_times_256Hz.pdf
Attachment 4: error_vs_N_for_different_times_512Hz.pdf
error_vs_N_for_different_times_512Hz.pdf
Attachment 5: error_vs_srate_for_different_times_256.pdf
error_vs_srate_for_different_times_256.pdf
Attachment 6: error_vs_srate_for_different_times_512.pdf
error_vs_srate_for_different_times_512.pdf
Attachment 7: error_vs_srate_for_different_times_1024.pdf
error_vs_srate_for_different_times_1024.pdf
Attachment 8: error_vs_time_for_different_srates_256.pdf
error_vs_time_for_different_srates_256.pdf
Attachment 9: error_vs_time_for_different_srates_512.pdf
error_vs_time_for_different_srates_512.pdf
Attachment 10: error_vs_time_for_different_srates_1024.pdf
error_vs_time_for_different_srates_1024.pdf
  12562   Fri Oct 14 15:47:00 2016 ranaUpdateTreasurefilters + clip

I say just fix the clipping. Don't worry about the PRM OSEM filters. We can do that next time when we put in the ITM baffles. No need for them on this round.

  1418   Mon Mar 23 15:50:44 2009 ranaConfigurationLSCfilters deleted, lsc rebooted

The LSC time had gone too high. I deleted ~20 filters and rebooted. CPU time came down to 50 usec.

The filters all looked like old trash to me, but its possible they were used.

I didn't delete anything from the DARM, CARM, etc. banks but did from the PD and TM filter banks. You can always go back in time by using the

filter_archive/

  5355   Wed Sep 7 08:14:01 2011 steveUpdateSUSfinal OSEM check

All fine, except ITMX_sensor_UL's  60  counts deep hoop for an hour.

Attachment 1: finalcheck.jpg
finalcheck.jpg
Attachment 2: ITMX10min.jpg
ITMX10min.jpg
Attachment 3: finalsum.png
finalsum.png
  13704   Mon Mar 26 16:10:33 2018 KiraUpdatePEMfinal setup sketch

I made sketches of the final setup. There will be a box in the rack that contains both the heater circuit and the temperature sensor boards. One of them is in the loop while the other isn't. Instead of having many cables leading to the can, there will only be these three, though they can be made into a single wire. It will be connected to the can through a D-9 connector. The second attachment is what will be inside of the box, with all the major wires and components labeled.

-----

Edit: I've canged the layout to (hopefully) make the labels easier to read. I've also added in a cable to the ADC that reads out the voltage across the 1 ohm resistor. I also attached the circuit diagrams for the heater circuit and the temperature sensors. The one for the heater circuit was made by Kevin and I used the same design, except I have LM7818 and LM7918, since the 15V ones were not available at the time I made the circuit. 

In addition, all the wires leading to the can will all be part of one bundle of wires (I didn't clearly indicate it as such). There will be a total of 6 wires: two are needed for the wire to supply power to the heater and will have a LEMO connector on the rack end and two are needed for each temperature sensor, which will be attached to the board directly on the rack end. 

Also, we don't need two voltage regulators for each temperature circuit. We can just have one of each of LM7815 and LM7915 to supply +/- 15V to the boards.

Attachment 1: heater_1_new.png
heater_1_new.png
Attachment 2: heater_2_new.png
heater_2_new.png
Attachment 3: HeaterCircuit.pdf
HeaterCircuit.pdf
Attachment 4: temp_sensor.png
temp_sensor.png
  13759   Wed Apr 18 12:18:39 2018 KiraUpdatePEMfinal setup sketch

I've updated the sketches and added in front panels for the seismometer block and the 1U panel (attachments 3 and 4). There was an issue when it came to the panel on the block because the hole is only big enough for the cable that already exists there and there is no space to add in the D-9 connector. Not quite sure how to resolve this issue. Attachment 7 is the current panel on the seismometer block. Attachments 5 and 6 are the updated temperature circuit and the heater circuit.

The boxes will be located in the short racks at EX and EY to minimize cable length.

Attachment 1: heater_1_new.png
heater_1_new.png
Attachment 2: heater_2_new.png
heater_2_new.png
Attachment 3: 1U-panel.pdf
1U-panel.pdf
Attachment 4: EX-can-panel.pdf
EX-can-panel.pdf
Attachment 5: IMG_20180412_120427.jpg
IMG_20180412_120427.jpg
Attachment 6: HeaterCircuit.pdf
HeaterCircuit.pdf
Attachment 7: IMG_20180418_121115.jpg
IMG_20180418_121115.jpg
  13782   Tue Apr 24 09:10:20 2018 KiraUpdatePEMfinal setup sketch

I've attached the final sketch for the panel on the granite block.

Attachment 1: EX-can-panel_1.pdf
EX-can-panel_1.pdf
  13800   Mon Apr 30 15:36:18 2018 KiraUpdatePEMfinal setup sketch

I've attached a sketch of how the panel will be mounted. We should make a small rectangular box that would raise the panel from the block by 1 cm or so to allow the cables to fit into the hole in the block without getting bent. It also has to be airtight so maybe having a thin layer of rubber between the mount and block would be good.

Attachment 1: mount.png
mount.png
  13769   Thu Apr 19 12:23:30 2018 KiraUpdatePEMfinal setup sketch update

I've added in the dimensions to my sketch.

It seems like placing the two connectors right next to each other would allow both cables to just barely go through the hole in the block.

Quote:

Can you please add dimensions to the drawing, so we can see if things fit and what the cable lenghts need to be?

For the panel on the granite slab, we should use a thinner piece of metal and mount it with an offset so that the D-sub cable can be fished through the hole in the slab. The hole is wide enough for 2 cables, but not 2 connectors.

 

Attachment 1: heater_1_new.png
heater_1_new.png
Attachment 2: heater_2_new.png
heater_2_new.png
  13771   Thu Apr 19 18:23:51 2018 KiraUpdatePEMfinal setup sketch update

since we're just going from the short rack (not the tall rack) to the seismometer, can't we use a cable shorter than 45' ?

Quote:

I've added in the dimensions to my sketch.

the panel should be completely replaced like I described. We don't want to try to squeeze it in artificially and torque the wires. It just needs to be separated from the slab by a few more cm.

  13774   Fri Apr 20 15:07:45 2018 KiraUpdatePEMfinal setup sketch update

If we lay the cable along the floor then it should be around 6' to the current setup and about 20' to the actual seismometer.

Edit: 16 gauge wire should be good.

Quote:

since we're just going from the short rack (not the tall rack) to the seismometer, can't we use a cable shorter than 45' ?

 

  13760   Wed Apr 18 16:59:35 2018 ranaUpdatePEMfinal setup sketch: EX Seis

Can you please add dimensions to the drawing, so we can see if things fit and what the cable lenghts need to be?

For the panel on the granite slab, we should use a thinner piece of metal and mount it with an offset so that the D-sub cable can be fished through the hole in the slab. The hole is wide enough for 2 cables, but not 2 connectors.


Attached is a 8-day minute trend of the heater control signals, as well as the in-loop temperature sensor (which underestimates the true fluctuations; we really need an out-of-loop sensor attached to the can or seismometer).

You can see that since the last tuning (on the 13th), its been stable at the set point of 39 C with 8.5 - 10 W of heating power. Need to add the PID loop settings (all the sliders on the MEDM screen) to the frames so that we can help in diagnosing. Also, fix the spelling of "Celcisususs".

Attachment 1: Screen_Shot_2018-04-18_at_5.20.53_PM.png
Screen_Shot_2018-04-18_at_5.20.53_PM.png
  4925   Thu Jun 30 21:00:20 2011 kiwamuUpdateABSLfine alignment done

(Just a quick report)

The fine alignment of the ABSL laser injection was successfully done.

I was able to see the DRMI fringings at the AS camera. The ABSL beam is injected from the AS port, therefore what I saw on the camera was the reflection back from the interferometer.

 

(Things to be done)

 -  A beat-note setup on the PSL table.

 - Refinement of the mode matching. The beam spot on the AS camera is a bit bigger, so I should more tightly focus the injected beam.

Quote from #4917

 - Fine alignments will be done tomorrow

  6230   Fri Jan 27 05:21:43 2012 kiwamuUpdateGreen Lockingfine alignment of the Y end green setup

I did a fine alignment on the Y end green setup. The green light became able to be locked again.

Quote from #6227

 The alignment is finished after the realization that the 3rd steering mirror had to be adjusted too.

  13979   Mon Jun 18 11:12:23 2018 KiraSummaryPEMfinishing up work at the lab

Since I am finishing my job at the lab, I have stored all my electronics in a box (attachment 1) and placed it under the table in the control room where some other electronics are stored. The box contains the heater circuit box, two temperature sensor boards, one temperature sensor, a short power cable and +/- 15V supply cables. In the lab I left the wires for the current setup and tied them down to the wall so that they aren't in the way (attachment 2). I left the can as is and the other temperature sensor is still attached to the inside of the can. I have labeled the wires going from the sensor as 'in' and 'out'. I've also left the wires for the heater there as well (attachment 3). I turned off the PID control and deactivated the tmux session on megatron.

Thanks to Rana and the LIGO team for giving me the opportunity to work at the 40m on this project with the seismometer.

Attachment 1: IMG_20180618_101640.jpg
IMG_20180618_101640.jpg
Attachment 2: IMG_20180618_093920.jpg
IMG_20180618_093920.jpg
Attachment 3: IMG_20180618_093932.jpg
IMG_20180618_093932.jpg
  11976   Thu Feb 4 10:19:05 2016 SteveUpdatesafetyfire marshal inspection

Pasadena fire marshal inspected the lab today. No violation was found.

  11901   Wed Dec 23 16:15:47 2015 ranaOmnistructureALARMfire alarm

Fire alarm went off several minutes ago. Talked to security and they said there was no fire. It beeped twice again just now. No one has been working on the IFO today.

  12216   Mon Jun 27 15:26:03 2016 SteveOmnistructureALARMfire alarm test

The fire alarm came on around 15:05  for about 2-3 minutes. We all  left the lab and counted heads.  I called Paul Mackel x2646 (cell 626/ 890- 3259) at Fire Protection Services. He said that this alarm test was planned and we should of got an email notice. Perhaps I missed that notes.

Quote:

Fire alarm went off several minutes ago. Talked to security and they said there was no fire. It beeped twice again just now. No one has been working on the IFO today.

 

Attachment 1: fireAlarmTest.png
fireAlarmTest.png
  11452   Tue Jul 28 15:05:09 2015 SteveUpdatesafetyfire alarm test ? no

We just had fire alarm trigged avacuation of the 40m lab.

It turned out that the CES building second floor sensor caused this action.

Attachment 1: 6minGaps.png
6minGaps.png
  708   Mon Jul 21 15:52:22 2008 steveBureaucracySAFETYfire alarms test
The fire alarm test and evacuation drill was successfully completed at 13:45 Wednesday, July 16, 2008

Everybody was on time for the 40m meeting.
  8026   Thu Feb 7 17:24:13 2013 SteveUpdateSAFETYfire extinguishers checked

The fire department weighted and pressure checked our units today. Surprisingly they found one powder filled can. We can only use HALON  gas in the lab.

 

  9090   Fri Aug 30 08:08:29 2013 steveUpdatesafetyfire horns-flashers tested OK

 

 We had fire alarm tests  and evacuation drills at 1:30pm yesterday. All flashers and horns are functioning unbearably loud and bright including clean assembly room.

  14812   Thu Jul 25 14:28:03 2019 gautamConfigurationComputersfirewalld disabled for EPICS CA

I think rana did some more changes to this workstation to make it useful for commissioning activities - but the MEDM screens were still white blanks. The problem was that the firewalld wasn't disabled (last two steps of the KThorne setup wiki). I disabled it. Now donatella can run MEDM, ndscope and StripTool. DTT doesn't work to get online data because of a "Synchronization Error", I'm not bothering with this for now. I think Kruthi successfully demonstrated the fetching of offline data with DTT.

Attachment 1: donatellaCommissioning.png
donatellaCommissioning.png
  8661   Fri May 31 10:25:17 2013 steveUpdatesafetyfirst aid kits refilled

Quote:

 

                                                 Recommended correction list:

1,  refill- upgrade first aid boxes

2,  maintain 18" ceiling to bookshelf clearance so the ceiling fire sprinklers are not blocked: room 101

3,  label chilled water supply & return valves in IFO room

4,  calibrate bake room hoods annually

5,  update safety sign at fenced storage

 

              40m still to do list:

1,   clean and measure all safety glasses

2,   annual crane inspection is scheduled for 8am March 19, 1013

3,   make PSL encloser shelf earthquake proof

 

Do you see something that is not safe? Add it to this list please.

 

 

 

Restocked First Aid Kits Location:

Main entrance, room 100

Drill press - above N2 cylinders, room 103

Control room, next to fire extinguisher, room  102

Vertex-north wall, IFO room 104

ETMY - right on ends light switches, IFO room 104_ east end

ETMX - on vertical I-beam of crane, IFO room 104_south end

Behind 1X3 Rack, on south wall - under instrument breakers panel PC-1, IFO room 104

 

Last thing remaining to be fixed from 2013 Safety Audit:

replace book shelf with 83" height

 

 

Attachment 1: refilledFAidK.jpg
refilledFAidK.jpg
  6063   Fri Dec 2 20:16:41 2011 DenUpdatedigital noisefirst order transition

In order to verify our theory about coherence corruption in linear systems due to the line

if((new_hist < 1e-20) && (new_hist > -1e-20)) new_hist = new_hist<0 ? -1e-20: 1e-20;  

in the /opt/rtcds/caltech/c1/core/release/src/include/drv/fm10Gen.c in the iir_filter function I've changed -20 to other numbers and watched at the coherence input and output of the digital filter cheby1("LowPass", 3, 0.1, 0.5)cheby1("LowPass", 6, 1, 1.5). The sampling rate was 2K. The frequency responce of the filter presented in this figure.

freqz.pdf

The next plot shows psd and coherence of the signal for different numbers in the if-statement line : 1e-20 , 1e-25, 1e-100.

 trans.pdf

We can see that for present value coherence between input and output signals is small even for low frequencies. The psd of the output signal is also corrupted because at low frequencies it should have the same psd as input signal. For 1e-25 and 1e-100 we can see that coherence is close to 1 at low frequencies so if-statement does not work and we have a first order transition from bad to good filter performance with discontinious jump of coherence.

However, for 1e-25 and 1e-100 data is still corrupted by the round-off error. Lack of coherence for high frequencies can be explained by the fact that dtt tools use single precision for data analysis and output is too small to plot a right coherence. But the coherence is also not precisely 1 for low frequencies. Actually, it is 0.99 for this aggresive filter. We use double precision in the real-time code but still for such kinds of filters round-off error is present. As wrote Daniel Sigg for Cheby filter:  "You need a lot more digits than you may naively suspect. In the 8th order example, the output of each SOS is amplified by ~106. This regardless of the fact that the coefficients are all of order 1. If you require a level of 10-3 attenuation in the stop band, you would have lost 9 digits already. Then, add the fact that you have to do of order 104 subtractions to get from 16kHz to 12Hz, loosing another ~2 digits. On top, the high Q section is probably 10 worse than the others and you lost 12 digits. In a real example this may stack up even worse."

Next we need to figure out what effects does round-off error introduce in the performance of the interferometer.

  8238   Wed Mar 6 08:40:03 2013 SteveUpdateVACfirst scan of this pumpdown

 Pumpdown 75 - Maglev - day 12

Precondition: 66 days at atm, installed TIP-TILTs with coils that  replaced PZT-Jena input steering

 

Attachment 1: pd75m12d.png
pd75m12d.png
Attachment 2: pd75mRGA12d.png
pd75mRGA12d.png
  14329   Sun Dec 2 19:32:35 2018 ranaUpdateIOOfit times

need to vary start/stop times in fit to test for systematics

  11439   Thu Jul 23 15:41:41 2015 SteveUpdatePEMfitting ants with TERRO

Pasadena got 0.2" of  rain on Saturday. Temperatures were high with high humidity since than.The ants were back in the Control room east side benches.

We have started using TERRO Liquid Ant Baits in January 2015   This worked very well to this point.

Tree new packages were opened  yesterday and the ants are gone.

We can conclude that these baits must be replaced after 6 mounts.

The liquid baits contains BORAX  and it is safe.

 

  3478   Fri Aug 27 13:41:02 2010 kiwamuUpdateSUSfix watchdogs

 [Joe, Kiwamu]

We found that the vertex watchdogs were not correctly running.

After I powercycled c1susaux, the problem was fixed successfully.

 

The symptom: the watchdogs didn't disable the coil signal even when PD_VAR signals went larger than the threshold values PD_MAX_VAR.

Also we replaced the label by the correct name "C1SUSAUX" on a tag which was tied to the front end machine mounted on the new 1X5 rack.

  4691   Wed May 11 17:10:04 2011 kiwamuConfigurationElectronicsfixed : MC3 LL PD has no signal

[Valera / Kiwamu]

It was because of a loose connection. Pushing the connector solved the issue.

looseconnectionMC3.png

We really have to think about making reliable connections and strain reliefs.

Quote from #4685

Yesterday we found that MC3 OSEM LL PD did not have a sensible signal - the readback was close to zero and it was making MC move around. I disabled the PD LL so that the damping is done with just three face plus side PDs. There still no signal from MC3 LL PD today. It needs debugging.

 

  3788   Tue Oct 26 17:31:17 2010 yutaUpdateCDSfixed OPLEV stuff and MCL filters

(Joe, Yuta)

Background:

 We are currently working on getting rid of "white stuff" in MEDM screens.
 Today, we fixed OPLEV stuff, MCL filters, and time stamps.

What we did:
 1. Plugged in OPLEV cables to ADC2. (See this wiki page for wiring)

 2. Connected ADC2 and OPLEV in Simulink model and fixed MEDM screens for OPLEVs (Attached #1).

 3. Put MCL filters for BS,ITMX,ITMY,PRM,SRM.
  They don't need them, but just for getting rid of "white stuff."
  They are connected to the ground, so the outputs are always 0.

 4. Fixed "TIME_STRING"s in MEDM screens so that they show current time correctly.
  You only need to put text monitor with channel "C1:FEC-DCU_NODE_ID_TIME_STRING" into master files(DEFAULTNAME things) and run generate_master_screens.py.
  It will automatically sets DCU ID correctly!! (Great work, Joe!)
  See this wiki page for more info on making MEDM screens.

 5. Checked OPLEV for MC2 by pointing a laser pointer to QPD. (For MC2, OPLEV is just a transmission beam position monitor)
  Each quadrant looked like they are connected to the right channel numbers.

Plan:
 - figure out what C1:SUS-NAME_MODE_SW1 does and fix
 - fix Whitening, Dewhitening ON/OFF button in main MEDM screens, so that they switch every channels' filters
 - make a new screen for MC (like the old one C1IOO_ModeCleaner.adl)
 - create a new mark for new MEDM screens

Attachment 1: optlevMC2.png
optlevMC2.png
  3789   Tue Oct 26 21:27:02 2010 JenneUpdateCDSfixed OPLEV stuff and MCL filters

Since MC2_TRANS is, in fact, MC2 Transmission, and not an oplev at all (it's not red, and it's not a lever, although it does use a QPD), I propose that the name be changed to something sensical, since calling it an oplev is completely non-sensical.  The name change should happen sooner rather than later, to avoid confusion.

Quote:

(Joe, Yuta)

Background:

 Today, we fixed OPLEV stuff, MCL filters, and time stamps.

What we did:
 5. Checked OPLEV for MC2 by pointing a laser pointer to QPD. (For MC2, OPLEV is just a transmission beam position monitor)
  Each quadrant looked like they are connected to the right channel numbers.

 

  5454   Mon Sep 19 02:08:24 2011 kiwamuUpdateLSCfixed POP clipping

Actually the clipping of POP wasn't in the chamber but it was on the first lens on the optical bench.

So I repositioned the lens to avoid the clipping and now there are no clipping on POP.

Quote from #5445

We found that POP beam is clipped by the steering mirrors inside the tank.

 

  8550   Wed May 8 17:23:04 2013 JamieConfigurationCDSfixed direct IPC connection between c1als and c1mcs

As with the previous post, I eliminated and unnecessary hop through c1rfm for the c1als --> c1mcs connection for the ALS output to MC2 POS.

As a side note, we might considering piping the ALS signals into the LSC input matrix, elevating them to actual LSC error signals, which in some since they are.  It's just that right now we're routing them directly to the actuators without going through the full LSC control.

  3769   Sat Oct 23 03:36:05 2010 yutaUpdateCDSfixed filters for C1SUS, C1RMS, C1MCS

(Joe, Yuta)

Summary:

 This Monday, MC suspension damping got something wrong.
 We started to check filters and found that digital filters were wrong because of mis-conversion from old filter files to new files.
 We converted the file again, and with mutual understanding between Foton and us, we finally got correct filters(I hope!).

What we did:
 1. Merged filter files in old /cvs/cds/caltech/chans/ directory into C1SUS.txt(BS,ITMX,ITMY), C1RMS.txt(PRM,SRM), C1MCS.txt(MC123).

 2. Rebuilt the RT models in order to get a correct filter file header(they have list of filter modules).

 3. Concatenate the header with filter design part which we got from step1.

 4. Replaced 'N 2048' with 'N 16384'
   It replaces sampling rate of "XXSEN"s.

Basically, step1-4 was the same with what we did last time. We didn't changed the fitler coefficients, so Foton somehow changed the original filter design.
So, this time, we

 5. Deleted coefficients like we did on Tuesday (see elog #3774).

But Foton couldn't read the file correctly this time. Foton seemed to be unbeatable.
Even if we replaced the sampling rate, Foton kept saying 2048! (This is maybe because Foton's default value is 2048Hz. Everytime Foton notice some editting in the file, he destroys everything. He hates editting)
The problems were always associated with the sampling rate, so

 6. Got back to step4 and undo-ed the replacement.

 7. Foton could read it this time, so I changed the sampling rate one by one using Foton GUI.

 8. Checked filters using Foton's Bode Plot.(Not for all, but some that had problem before)

 9. Splitted SDSEN filters to SDSEN, SUSSIDE, and SDCOIL.

 10. Put some missing whitening filters, and 28HzELPs.
   BS, PRM, SRM didn't have any 28HzELP for SDCOIL.
   ITMX and ITMY SDCOIL had SimDW/InvDW which doesn't make sense(SIDEs don't have analog DW). So, I deleted and replaced with 28HzELP.

F2A issue:
 We failed in sending F2A filters to new filter files.
 These are a little bit complicated because TO_COIL_X_X filters were named ULPOS,URPOS etc before.
 Also, MC3 didn't have any F2As, so maybe we should but the same F2As as MC1/2.
 Note that every F2As are different, and TO_COIL matrix have UL,UR,LL,LR order(not same as INMATRIX).
 Also, SRM had f2pv instead of F2A!

Next work:
 - Check whole filters by actually measuring transfer function between SENs and COILs.
 - Damp MC suspentions, and lock MC.
 - Measure openloop TF and compare with the designed.


How do you read a Foton filter file:
 When you open up a Foton filter file, you see filters like this.

################################################################################
### modulename                                                               ###
################################################################################
# SAMPLING modulename samplingrate
# DESIGN   modulename n filterdesign
# DESIGN   modulename n filterdesign
###                                                                          ###
modulename   n xy z      v      w filtername                        gain    a1     a2    b1     b2
modulename   n xy z      v      w filtername                        gain    a1     a2    b1     b2
                                                                            a1     a2    b1     b2
n: filter number
 0 for FM1, 1 for FM2, ... , 9 for FM10

x: Input Switching setting
 1 Always On
 2 Zero History

y: Output Switching setting
 1 Immediately
 2 Ramp
 3 Input Crossing
 4 Zero Crossing

z: number of filters cascaded.

v: if y=2, (Ramp Time(sec))*(samplingrate)
   if y=3 or 4, Tolerance

w: (Timeout(sec))*(samplingrate)

 Note that v and w are changed when sampling rate is changed.

 Transfer function will be;
  H(1/z)=G*(1+b1/z+b2/z/z)/(1+a1/z+a2/z/z)
  z=exp(s/fs)

 where fs is the sampling frequency.

Reference:
 Kiwamu Izumi: "Notes about Digital Filters," http://tamago.mtk.nao.ac.jp/izumi/green/DigitalFilter.pdf

  3744   Wed Oct 20 01:22:18 2010 yutaUpdateCDSfixed filters for MCs, but no damping

(Rana, Yuta)

Summary:

 The damping servo for MCs has not been working since Monday.
 We already found that some filter coefficients were wrong.(see elog #3742)
 So, we fixed it (just for MCs now).
 But still doesn't work.

What we did:
Fixed the filters for MC suspensions;
 1. In /cvs/cds/rtcds/caltech/c1/chans/ directory, we replaced C1MCS.txt with ./filter_archive/c1mcs/C1MCS_101019_101927.txt.
  This is the archive of the filter bank for MC suspensions, when filter designs were correct(when we hadn't opened it with foton yet).

 2. Deleted all the filter coefficients.
   By using emacs magical C-<space> C-x r k.

 3. Loaded with foton to get correct coefficients.

 4. Reloaded coefficients for C1MCS.

We now have the correct filters, but the damping still doesn't work.

 5. To confirm that the filters are now correct and the model is working correctly, we measured the transfer function between ULSEN input and ULCOIL output and compared with the calculated TF from the filter bank file (Attachment #1) .

 6. To calculate the designed function, we used the following matlab scripts;
    /cvs/cds/caltech/users/rana/mat/utilities/FotonFilter.m        # takes the foton file and returns the TF
    /cvs/cds/caltech/users/rana/mat/utilities/readFilterFile.m    # reads the foton file
    /cvs/cds/caltech/users/yuta/scripts/sentocoil.m                   # calculates the total TF from SEN to COIL

Result:
 As you can see from the attachment, filters seem fine now. (The red line is the measured and the blue line is the calculated function in the plot)
 But the damping (for POS, PIT, YAW) still doesn't work. Why????

Next work:

 - see if coils are pushing correctly
 - push cable connectors further!
 - check input and output filters (whitening, dewhitening)
 - when fixed, use my fully updated QAdjuster.py for adjusting Q for multiple channels automatically!!

Attachment 1: Screenshot.png
Screenshot.png
  16986   Mon Jul 11 17:25:43 2022 TegaUpdateVACfixed obsolete reference bug in serial_XGS600 service

Koji noticed that the FRG sensors were not updating due to reference to an obsolete modbusIOC_XGS service, which was used temporarily to test the operation of the serial XGS sensor readout to EPICS. The information in this service was later moved into modbusIOC.service but the dependence on the modbusIOC_XGS.service was not removed from the serial_XGS600.service. This did not present any issue before the shutdown, probably bcos the obsolete service was already loaded but after the restart of c1vac, the obsolete service file modbusIOC_XGS.service was no longer available. This resulted in  serial_XGS600.service throwing a failure to load error for the missing obsolete modbusIOC_XGS service. The fix involved replacing two references to 'modbusIOC_XGS' with 'modbusIOC' in  /opt/target/services/serial_XGS600.service.

I also noticed that the date logged in the commit message was Oct 2010 and that I could not do a push from c1vac due to an error in resolving git.ligo.org. I was able to push the commit from my laptop git repo but was unable to do a pull on c1vac to keep it synced with the remote repo.

ELOG V3.1.3-