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ID Date Author Typeup Category Subject
  12123   Fri May 20 00:06:19 2016 VarunUpdateGeneralSURF 2016

I have written a basic version of AGC, and have done some tests with a data file. will do tests on whitening and agc today. Also, today I have to go to the SSN office. Hence will be late.

 

-Varun

Quote:

Finished writing the code on whitening. I have to still test it. uploaded on github noise cancellation repo. @eric could you give me some data of noise power spectral density for testing the code?

-Varun

Quote:

Hello, I am Varun Kelkar. I will be working at the 40m lab as a SURF student this summer with Eric Quintero on Audio processing for real time control system signals. This week I will mostly be working on implementing basic DSP C-code offline. Currently I am trying to write a code for noise whitening.

-Varun

 

 

  12124   Fri May 20 17:36:06 2016 gautamUpdateLSCNew stands for TransMon/Oplev QPDs

As we realized during the EX table switch, the transmitted beam height from the arm is not exactly 4" relative to the endtable, it is more like 4.75" at the X-end (yet to be investigated at the Y-end). As a result, the present configuration involves the steering optics immediately before the Oplev and TransMon QPDs sending the beam downwards at about 5 degrees. Although this isn't an extremely large angle, we would like to have things more level. For this purpose, Steve has ordered some Aluminium I-beams (1/2 " thick) which we can cut to size as we require. The idea is to have the QPD enclosures mounted on these beams and then clamped to the table. One concern was electrical isolation - but Steve thinks Delrin washers between the QPD enclosure and the mount will suffice. We will move ahead with getting these machined once I investigate the situation at the Y end as well.. The I beams should be here sometime next week...

  12127   Mon May 23 17:47:51 2016 VarunUpdateGeneralSURF 2016

Tested the AGC today with LSC cavity transmission signal and error signal. Not in real time still.

Key to attachments:

cav_tr-eps-converted-to.pdf: LSC cavity transmission signal input

cav_tr_out-eps-converted-to.pdf: LSC cavity transmission signal, output of the AGC.

Attachment 1: cav_tr-eps-converted-to.pdf
cav_tr-eps-converted-to.pdf
Attachment 2: cav_tr_out-eps-converted-to.pdf
cav_tr_out-eps-converted-to.pdf
Attachment 3: err-eps-converted-to.pdf
err-eps-converted-to.pdf
Attachment 4: err_out-eps-converted-to.pdf
err_out-eps-converted-to.pdf
  12129   Tue May 24 17:55:17 2016 VarunUpdateElectronicsUsing Altium

Contacted Charles regarding use of Altium. Got to know that Altium is installed on cit40m iMac in Win7 on VirtualBox. Had to update Virtualbox to get it working. Altium now works for sometime, but then fails, saying that it is unlicensed.

  12130   Tue May 24 22:49:02 2016 gautamUpdateCOCFinesse modelling - mode overlap scans

Summary:

Having played around with a toy finesse model, I went about setting up a model in which the RC folding mirrors are not flipped. I then repeated the low-level tests detailed in the earlier elog, after which I ran a few spatial mode overlap analyses, the results of which are presented here. It remains to do a stability analysis.

Overview of model parameters (more details to follow):

  • PRC length = 6.7727m (chosen using l_{PRC} = (N+\frac{1}{2})\frac{c}{2f_1}, N=0 - I adjusted the position of the PRM to realize this length in the model, while leaving all the other vertex optics in the same positions as in elog 9590
  • SRC length = 5.4182 (chosen using l_{SRC} = M\frac{c}{2f_2} but not l_{SRC} = N\frac{c}{2f_1}, M and N being integers, for M=2 - as above, I adjusted the position of the SRM to realize this in the model, while leaving all other vertex optics in the same positions as in elog 9590. It remains to be verified if it is physically possible to realize these dimensions in vacuum without any beam clipping etc but I think it should be possible seeing as the PRM and SRM had to be moved by less than 2cm from their current positions..
  • For the losses, I used the most recent numbers we have where applicable, and put in generic 25ppm loss for all the folding mirrors/BS/AR surfaces of arm cavity mirrors/PRM/SRM. Arm round trip loss was equally distributed between ITMs and ETMs
  • Arm lengths used: L_X = 37.79m, L_Y = 37.81m
  • To set the "tunings" of the various mirrors, I played around with a few configurations to see where the various fields resonated - it turns out that for PRM, ITMX, ITMY, ETMX and ETMY, the "phase" in the .kat file can be set as 0. while that for the SRM can be set as 90. In the full L1/H1 interferometer .kat files, these are tuned even further to the (tenth?!) decimal place, but I think these values suffice for out purposes.

Results (general note: positive RoC in these plots mean a concave surface as seen by the beam):

  • Attachments #1, #2 and #3 reproduce the low-level tests performed earlier for this updated model - i.e. I look at the arm transmission with no PRM/SRM, circulating PRC power with no ETMs, and circulating SRC power with no ETMs. Everything looks consistent here... In Attachment #2, there is no legend, but the (almost overlapping) red and green lines are meant to denote the +f1 and +f2 sidebands.
  • Attachments #4 and #5 are a summary of the mode-overlap scans for the PRC and SRC. What I did was to vary the radius of curvature of the RC mirrors (finesse only allows you to vary Rcx and Rcy, so I varied both simultaneously) and calculate the mode overlap between the appropriate pairs of cavities (e.g. PRX and XARM) in the tangential and saggital planes. The take-away here is that there is ~5% mode-mismatch going from an RoC of 1000m to 300m. I've also indicated the sag corresponding to a given RoC - these are pretty tiny, I wonder if it is possible to realize a sag of 1um? I suppose it is given that I've regularly seen specs of surface roughness of lambda/10?
  • Attachment #6 shows the PRC gain (calculated as T_PRC * (transmitted arm power with PRM / transmitted arm power without PRM) as a function of the RoC of PR2 and PR3. As a sanity check, I repeated this calculation with lossless HR surfaces (but with nominal 25ppm losses for AR surfaces of ITMs, and BS etc), shown in Attachment #7. I think these make sense too...
  • Attachment #8 - in order to investigate possible mode mismatch between the arm modes due to different radii of curvature of the ETMs, I kept the ETMY RoC fixed at 57.6m and varied the ETMY RoC between 50m and 70m (here, I've plotted the mode matching efficiency as a function of the RoC of the ETM in the X and Y directions separately - the mode overlap is computed as \frac{1}{\sqrt{2}}(x^2 + y^2) where x and y denote the overlap in the tangential and saggital planes respectively. It would seem that we only lose at most a couple of percent even if the RoCs are mismatched by up to 10m...
  • Attachment #9 - .kat file and the various pykat scripts used to generate these plots...

Next step is to carry out a stability analysis...

Attachment 1: armTransmission.pdf
armTransmission.pdf
Attachment 2: prcFSR.pdf
prcFSR.pdf
Attachment 3: srcTransmission.pdf
srcTransmission.pdf
Attachment 4: modeMatchPRX.pdf
modeMatchPRX.pdf
Attachment 5: modeMatchSRX.pdf
modeMatchSRX.pdf
Attachment 6: PRCgainScan.pdf
PRCgainScan.pdf
Attachment 7: PRCgainLossless.pdf
PRCgainLossless.pdf
Attachment 8: armModeMatchScan.pdf
armModeMatchScan.pdf
Attachment 9: Finesse_files.zip
  12131   Tue May 24 23:17:37 2016 ericqUpdateCOCFinesse modelling - mode overlap scans

I think you should use the current actual PRC & SRC cavity lengths as measured, as it would be simplest to simply replace the folding mirror optics without changing the macroscopic lengths / optic positions. (EDIT: Gautam rightly points out that we have to move things around regardless, since our current lengths include propagation through the folding mirror subtrates)

Moreover, the recycling cavity lengths you posted are not the right "ideal" lengths to use, as they do not account for the complex reflectivities of the sidebands off of the arm cavities (I have made this mistake myself). See this 40m wiki page for details.

In short, given our current modulation frequency, the ideal lengths to use would be:

  • Ideal arm length of 37.795 m
  • Ideal PRC length of 6.753 m
  • Ideal SRC length of 5.399 m

These are the lengths that the recycling cavity optics were positioned for (though we did not achieve them perfectly). If you do a finer PRC/SRC length scan around the DRFPMI resonance of your model, you would presumably see some undesired sideband splitting. 

  12132   Wed May 25 02:54:09 2016 ericqUpdateGeneralOdds and ends

WFS locking point seemed degraded; I hand aligned and reset the WFS offsets as usual.

ITMX oplev recentered. While doing so, I noticed an ETMX excursion rear its head for the first time in a long while :crying

There was no active length control on ETMX, only OSEM damping + oplevs. Afterwards, its still moving around with only local damping on. I'm leaving the oplevs off for now.

  12133   Wed May 25 08:32:55 2016 SteveUpdateSUSlocal EQ 3.5m

Local EQ 3.5 mag  at 2:28 UTC May 24, 2016 Rancho Cucamonga, Ca.....no damage

 

Attachment 1: 3.5Cucam.png
3.5Cucam.png
Attachment 2: local3.5cucam.png
local3.5cucam.png
  12134   Wed May 25 11:51:40 2016 SteveUpdatesafetySURF 2016 safety
Quote:

Hello, I am Varun Kelkar. I will be working at the 40m lab as a SURF student this summer with Eric Quintero on Audio processing for real time control system signals. This week I will mostly be working on implementing basic DSP C-code offline. Currently I am trying to write a code for noise whitening.

-Varun

Varun has received 40m specific basic safety training today.

  12135   Wed May 25 14:21:29 2016 Max IsiUpdateGeneralSummary page configuration

I have modified the c1summary.ini and c1lsc.ini configuration files slightly to avoid overloading the system and remove the errors that were preventing plots from being updated after certain time in the day.

The changes made are the following:
1- all high-resolution spectra from the Summary and LSC tabs are now computed for each state (X-arm locked, Y-arm locked, IFO locked, all);
2- I've removed MICH, PRCL & SRCL from the summary spectrum (those can still be found in the LSC tab);
3- I've split LSC into two subtabs.

The reason for these changes is that having high resolution (raw channels, 16kHz) spectra for multiple (>3) channels on a single tab requires a *lot* of memory to process. As a result, those jobs were failing in a way that blocked the queue, so even other "healthy" tabs could not be updated.

My changes, reflected from May 25 on, should hopefully fix this. As always, feel free to re organize the ini files to make the pages more useful to you, but keep in mind that we cannot support multiple high resolution spectra on a single tab, as explained above.

  12136   Wed May 25 14:29:31 2016 VarunUpdateGeneralSURF 2016

Edited the AGC to include overlapping frames yesterday. forgot to put an elog on it!

Quote:

Tested the AGC today with LSC cavity transmission signal and error signal. Not in real time still.

Key to attachments:

cav_tr-eps-converted-to.pdf: LSC cavity transmission signal input

cav_tr_out-eps-converted-to.pdf: LSC cavity transmission signal, output of the AGC.

 

  12137   Thu May 26 18:10:48 2016 VarunUpdateGeneralSURF 2016

Wrote and tested a function for downconversion. It contains a mixer with a sinusoidal input for modulation with the desired frequency and a 2nd order butterworth low pass filter to remove the higher frequency-shifted part of the modulated signal. I have tested this with input of 2kHz giving a good output of 200 Hz on the speaker. Codes are uploaded on github, will update the real time document tomorrow.

 

-Varun

Quote:

Edited the AGC to include overlapping frames yesterday. forgot to put an elog on it!

Quote:

Tested the AGC today with LSC cavity transmission signal and error signal. Not in real time still.

Key to attachments:

cav_tr-eps-converted-to.pdf: LSC cavity transmission signal input

cav_tr_out-eps-converted-to.pdf: LSC cavity transmission signal, output of the AGC.

 

 

Attachment 1: input.png
input.png
Attachment 2: output.png
output.png
  12138   Fri May 27 02:52:53 2016 ericqUpdateLSCRestoring high BW single arm control

I've been futzing with the common mode servo, trying to engage the AO path with POY for high bandwidth control of a single arm lock. I'm able to pull in the crossover and get a nice loop shape, but keep getting tripped up by the offset glitches from the CM board gain steps, so can't get much more than a 1kHz UGF.

As yutaro measured, these can be especially nasty at the major carrier transitions (i.e. something like 0111->1000). This happens at the +15->+16dB input gain step; the offset step is ~200x larger than the in-loop error signal RMS, so obviously there is no hope of keeping the loop engaged when recieving this kind of kick. Neither of the CM board inputs are immune from this, as I have empirically discovered. I can turn down the initial input gain to try and avoid this step occuring anywhere in the sequence, but then the SNR at high frequencies get terrible and I inject all kinds of crud into the mode cleaner, making the PC drive furious.

I think we're able to escape this when locking the full IFO because the voltages coming out of REFL11 are so much larger than the puny POY signals so the input-referred glitches aren't as bad. I think in the past, we used AS55 with a misaligned ITMX for this kind of single arm thing, which probably gives better SNR, but the whole point of this is to keep the X arm aligned and lock it to the Y-arm stabilized PSL. 

  12139   Fri May 27 11:54:22 2016 VarunUpdateGeneralPackage delivery

A package labelled 'UPS Ground' has arrived.

-Varun

  12140   Mon May 30 18:19:50 2016 JohannesUpdateCDSASS medm screen update

I noticed that the TRY button in the ASS main screen was linking to LSC_TRX instead of LSC_TRY. Gautam fixed it.

  12141   Tue May 31 16:52:58 2016 SteveUpdatesafetyNONO

Please do not place anything on the top of the cabinets that is not tied down. It will end up on our head in an earth quake.

 

Attachment 1: nono.jpg
nono.jpg
  12142   Wed Jun 1 09:06:38 2016 SteveUpdateLSCNew stands for TransMon/Oplev QPDs

Machined from I-beam 6061 T6 Aluminum 5" x 0.5 x 3.25

Quote:

As we realized during the EX table switch, the transmitted beam height from the arm is not exactly 4" relative to the endtable, it is more like 4.75" at the X-end (yet to be investigated at the Y-end). As a result, the present configuration involves the steering optics immediately before the Oplev and TransMon QPDs sending the beam downwards at about 5 degrees. Although this isn't an extremely large angle, we would like to have things more level. For this purpose, Steve has ordered some Aluminium I-beams (1/2 " thick) which we can cut to size as we require. The idea is to have the QPD enclosures mounted on these beams and then clamped to the table. One concern was electrical isolation - but Steve thinks Delrin washers between the QPD enclosure and the mount will suffice. We will move ahead with getting these machined once I investigate the situation at the Y end as well.. The I beams should be here sometime next week...

Atm2, version 2 "pdstand" will allow you to clamp from any direction ( Koji was right )

Attachment 1: pdIb.PDF
pdIb.PDF pdIb.PDF
Attachment 2: pdstand.pdf
pdstand.pdf
  12143   Wed Jun 1 11:19:14 2016 VarunUpdateGeneralUpdate of work till now

Completed:

Wrote and tested a code for AGC using cavity transmission signal and length error signal.

Wrote and tested a code for frequency shifting (downconversion) using mixing and LPF

Wrote a code for whitening using FFT.

Altium working on cit40m iMac

Plans:

Writing codes for Frequency warping and whitening in time domain.

Implement AGC and frequency shifting on the real time control system.

Calculate requirements for Anti-aliasing filter.

  12144   Wed Jun 1 15:01:56 2016 SteveUpdateSUS wire standoffs update

There are some issues with 5 mm sapphire prism Atm5. It will cause  interference between one of the prisms and the Side OSEM.

Here are some drawings to see the issues with larger wire standoff.

The 2 mm prism will work.with a 1 mm longer dumbell.

Quotes requested from http://photomachining.com/laser-micromachining-photomachining-contact.html and http://www.optocity.com/ 

 

 

Attachment 1: 06011603.PDF
06011603.PDF
Attachment 2: 06011602.PDF
06011602.PDF
Attachment 3: sapphire_stand_off_v2.pdf
sapphire_stand_off_v2.pdf
Attachment 4: side_OSEM_ETMY.jpg
side_OSEM_ETMY.jpg
Attachment 5: 5p2wsf.png
5p2wsf.png
  12145   Wed Jun 1 16:28:28 2016 ericqUpdateElectronicsCommon board Op amp input offsets

I used a Eurocard extension board to peek at the inputs and outputs of each of the gain-ladder AD829s on input B of the CM board in the +31dB configuration with the input terminated. (i.e with the following stages active in this order: +16dB, +8dB, +4dB, +2dB, +1dB).

The voltages I observed imply that the +8dB stage has an input voltage offset of -2mV, whereas all the other positive gain stages show around +-0.5mV. This could explain the shift observed at the +15->+16 transition. (However, since both input channels show a jump here, maybe its something more systemic about the board...)

In any case, it should be simple enough to swap out a new AD829 in place of U9B and see if it improves things, before getting too deep into the muck. (In principle, the AD829 has offset nulling pins, but I'm not sure how to do it in a non-hacky way since the board doesn't have any pads for it.)

  12146   Thu Jun 2 16:35:44 2016 KojiUpdateSUS wire standoffs update

Gap of the prism from the mirror

Sag: s = R(1-Cos[ArcSin[d/2/R]])

- Mirror curvature sag for 2mm prism (R=37.75mm): s=13um

- Minimum gap: 20um => s=33um => R=15mm

- Nominal gap: 35um => s=48um => R=10mm

- Maximum gap: 50um => s=63um => R=8mm


The second figure shows somewhat realistic arrangement of the pieces

Attachment 1: sapphire_stand_off_v3.pdf
sapphire_stand_off_v3.pdf
Attachment 2: arrangement-v3.pdf
arrangement-v3.pdf
  12147   Fri Jun 3 12:53:44 2016 ericqUpdateElectronicsCommon board Op amp input offsets

I replaced some of the AD829s with other AD829s, but the offset situation didn't improve.

However, I figured that we don't really need the ~100MHZ bandwidth of the AD829, since the IMC loop limits us to a ~10kHz CARM bandwidth. Also, since we don't routinely use IN2 for anything, I felt free to try something else. 

Specifically, I replaced all of the positive gain AD829s in the input 2 gain ladder with OP27s (U8B->U12B on D1500308), which should have input offset voltages ~30x lower than the AD829s. 

Here is a comparison of the outputs these configurations perform, normalized to the output at the +0dB gain setting - where all of the op amps in the gain ladder are bypassed. 

So, most of the transitions now result in an output offset change of less than 0.5mV, which is nice.

The exception seems to be where the +8dB stage is switched in or out. I may try replacing this one, as these transitions cause a lock loss now when trying to lock the arm with high bandwidth using POY.

  12148   Fri Jun 3 13:05:18 2016 ericqUpdateCDSCDS Notes

Some CDS related things:


Keith Thorne has told us about a potential fix for our framebuilder woes. Jamie is going to be at the 40m next week to implement this, which could interfere with normal interferometer operation - so plan accordingly. 


I spent a little time doing some plumbing in the realtime models for Varun's audio processing work. Specifically, I tried to spin up a new model (C1DAF), running on the c1lsc machine. This included:

  • Removing the unused TT3 and TT4 parts from the IOO block in c1ass.mdl, freeing up some DAC outputs on the LSC rack
  • Adding an output row to the LSC input matrix which pipes to a shared memory IPC block. (This seemed like the simplest way for the DAFI model to have access to lots of signals with minimal overhead).
  • Removing two unused ADC inputs from c1lsc.mdl (that went to things like PD_XXX), to give c1daf.mdl the required two ADC inputs - and to give us the option of feeding in some analog signals.
  • Editing the rtsystab file to include c1daf in the list of models that run on c1lsc
  • Editing the existing DAFI .mdl file (which just looked like an old recolored cut-n-paste of c1ioo.mdl) to accept the IPC and ADC connections, and one DAC output that would go to the fibox. 

The simple DAFI model compiled and installed without complaint, but doesn't succesfully start. For some reason, the frontend never takes the CPU offline. Jamie will help with this next week. Since things aren't working, these changes have not been commited to the userapps svn. 

  12149   Fri Jun 3 14:24:13 2016 SteveUpdateSUSlocal EQ 3.1 m

Local EQ 3.1 mag at Jun 2, 2016 11:06:16 PM UTC, Muscoy CA........no damage

Our STS should seen this shake.

 

Attachment 1: eq3.1mMuscoyCa.png
eq3.1mMuscoyCa.png
  12150   Fri Jun 3 17:56:14 2016 VarunUpdateGeneralDAFI update

Wrote and tested a phase vocoder, with two of its applications:

1) Time scaling: This enables change of time duration without affecting the pitch.

2) Frequency warping: This changes the pitch of the sound without affecting the time duration.

1 & 2 tested offline with cavity transmission signal. 1) gives speedup of 2, and 2 gives frequency warping (pitch lowering by a factor of 2)

codes uploaded on github repo

  12151   Mon Jun 6 16:41:36 2016 ericqUpdateCDSFB upgrade work

Barring objections, starting tomorrow morning, Jamie will be testing the new FB code. The IFO will not be available for other use while this is ongoing.

  12152   Tue Jun 7 11:12:47 2016 jamieUpdateCDSDAQD UPGRADE WORK UNDERWAY

I am re-starting work on the daqd upgrade again now.  Expect the daqd to be offline for most of the day.  I will report progress.

  12153   Tue Jun 7 17:21:13 2016 AakashUpdateGeneralSURF 2016

Hi!

I am Aakash Patil. I will be working at the 40m lab as a SURF student with Gautam Venugopalan on enclosures for seismometers to shield them from thermal and magnetic fluctuations. This week I will be working on the development of hardware for four probe measurement along with a constant current source. It will effectively help us in accurate temperature measurement throughout the development of enclosure.

 

  12154   Tue Jun 7 18:20:18 2016 VarunUpdateGeneralDAFI update

Tried to implement AGC on FE. Had some trouble bringing the code into the correct form. It looks okay now. However, this agc code as well as idenntity code (input = output) doesnt seem to build on the c1lsc FE. Have not tried too many debugging steps yet, will come and check the problem tomorrow. 

-Varun

Quote:

Wrote and tested a phase vocoder, with two of its applications:

1) Time scaling: This enables change of time duration without affecting the pitch.

2) Frequency warping: This changes the pitch of the sound without affecting the time duration.

1 & 2 tested offline with cavity transmission signal. 1) gives speedup of 2, and 2 gives frequency warping (pitch lowering by a factor of 2)

codes uploaded on github repo

 

  12155   Tue Jun 7 20:49:50 2016 jamieUpdateCDSDAQD work ongoing

Summary: new daqd code running overnight test on fb1.  Stability issues persist.

The code is from Keith's "tests/advLigoRTS-40m" branch, which is a branch of the current trunk.  It's supposed to include patches to fix the crashes when multiple frame types are written to disk at the same time.  However, the issue is not fixed:

2016-06-07_20:38:55 about to write frame @ 1149392336
2016-06-07_20:38:55 Begin Full WriteFrame()
2016-06-07_20:38:57 full frame write done in 2seconds
2016-06-07_20:39:11 about to write frame @ 1149392352
2016-06-07_20:39:11 Begin Full WriteFrame()
2016-06-07_20:39:13 full frame write done in 2seconds
2016-06-07_20:39:27 about to write frame @ 1149392368
2016-06-07_20:39:27 Begin Full WriteFrame()
2016-06-07_20:39:29 full frame write done in 2seconds
2016-06-07_20:39:43 about to write second trend frame @ 1149391800
2016-06-07_20:39:43 Begin second trend WriteFrame()
2016-06-07_20:39:43 about to write frame @ 1149392384
2016-06-07_20:39:43 Begin Full WriteFrame()
2016-06-07_20:39:44 full frame write done in 1seconds
2016-06-07_20:39:59 about to write frame @ 1149392400
2016-06-07_20:40:04 Begin Full WriteFrame()
2016-06-07_20:40:04 Second trend frame write done in 21 seconds
2016-06-07_20:40:14 [Tue Jun  7 20:40:14 2016] main profiler warning: 1 empty blocks in the buffer
2016-06-07_20:40:15 [Tue Jun  7 20:40:15 2016] main profiler warning: 0 empty blocks in the buffer
2016-06-07_20:40:16 [Tue Jun  7 20:40:16 2016] main profiler warning: 0 empty blocks in the buffer
2016-06-07_20:40:17 [Tue Jun  7 20:40:17 2016] main profiler warning: 0 empty blocks in the buffer
2016-06-07_20:40:18 [Tue Jun  7 20:40:18 2016] main profiler warning: 0 empty blocks in the buffer
2016-06-07_20:40:19 [Tue Jun  7 20:40:19 2016] main profiler warning: 0 empty blocks in the buffer
2016-06-07_20:40:20 [Tue Jun  7 20:40:20 2016] main profiler warning: 0 empty blocks in the buffer
2016-06-07_20:40:21 [Tue Jun  7 20:40:21 2016] main profiler warning: 0 empty blocks in the buffer
2016-06-07_20:40:22 [Tue Jun  7 20:40:22 2016] main profiler warning: 0 empty blocks in the buffer
2016-06-07_20:40:23 [Tue Jun  7 20:40:23 2016] main profiler warning: 0 empty blocks in the buffer

This failure comes when a full frame (1149392384+16) is written to disk at the same time as a second trend (1149391800+600).  It seems like every time this happens daqd crashes.

I have seen other stability issues as well, maybe caused by mx flakiness, or some sort of GPS time synchronization issue caused by our lack of IRIG-B cards.  I'm going to look to see if I can get the GPS issue taken care of so we take that out of the picture.

For the last couple of hours I've only seen issues with the frame writing every 20 minutes, when the full and second trend frames happen to be written at the same time.  Running overnight to gather more statistics.

  12156   Wed Jun 8 08:34:55 2016 jamieUpdateCDSDAQD work ongoing

38 restarts overnight.  Problem definitely not fixed.  I'll be reverting back to old daqd and fb this morning.  Then regroup and evaluate options.

  12157   Wed Jun 8 10:20:14 2016 SteveUpdatesafetySURF 2016 safety

Aakash Patil received 40m specific basic safety training.

Quote:
Quote:

Hello, I am Varun Kelkar. I will be working at the 40m lab as a SURF student this summer with Eric Quintero on Audio processing for real time control system signals. This week I will mostly be working on implementing basic DSP C-code offline. Currently I am trying to write a code for noise whitening.

-Varun

Varun has received 40m specific basic safety training today.

 

  12159   Wed Jun 8 16:12:38 2016 VarunUpdateGeneralDAFI update

Summary: I am implementing digital audio filtering on various interferometer signals in order to listen to the processed audio which will help in characterizing and noise reduction in the interferometer. Following is an implementation of an Automatic Gain control (AGC) block on an LSC input signal.

Details of AGC: Currently, the AGC code implemented on FE takes input to fill a frame, then calculates the power in each frame and gives an appropriate gain to it, so that the new power content is to the required level. It is then written to the output, frame by frame. The frame is currently a rectangular window. The frame length and hop size can be adjusted. Current values are as follows:

frame length is 512 samples

hop length is 128 samples.

The input and output are delayed by 1 frame.

Details of testing: Attachment 1 shows a simulink diagram of the DAF system. Eric made this and I modified it later on. Testing was done using signal from the "LSC1" channel. Attachments 2 and 3 show aquired input and output of the AGC respectively. Gain of the preamp of the LSC input signal was varied over a total time span of 200 s. Each gain value was kept for a duration of about 20 seconds. The varying power levels can be seen in the input plot.

The output shows a uniform power level throughout.

 

Quote:

Tried to implement AGC on FE. Had some trouble bringing the code into the correct form. It looks okay now. However, this agc code as well as idenntity code (input = output) doesnt seem to build on the c1lsc FE. Have not tried too many debugging steps yet, will come and check the problem tomorrow. 

-Varun

Quote:

Wrote and tested a phase vocoder, with two of its applications:

1) Time scaling: This enables change of time duration without affecting the pitch.

2) Frequency warping: This changes the pitch of the sound without affecting the time duration.

1 & 2 tested offline with cavity transmission signal. 1) gives speedup of 2, and 2 gives frequency warping (pitch lowering by a factor of 2)

codes uploaded on github repo

 

 

Attachment 1: dafi.png
dafi.png
Attachment 2: agcin.pdf
agcin.pdf
Attachment 3: agcout.pdf
agcout.pdf
  12160   Thu Jun 9 09:57:06 2016 AakashUpdateGeneralSeismometer Enclosure Development
Me and Gautam yesterday opened the tilt-free seismometer enclosure to see if we could use the thermocouples and
other things previously used by Megan. But we are planning to get new four-wire RTDs for our work.
For the next day or two, I will be trying to set up Acromag Busworks terminal so that the data logging during
this enclosure development experiment becomes perfect and easy. Johannes has sent me the wiki page URL for the same.
  12162   Thu Jun 9 15:14:46 2016 jamieUpdateCDSold fb restarted, test of new daqdon fb1 aborted for time being

I've restarted the old daqd on fb until I can figure out what's going on with the symmetricom driver on fb1.

Steve:  Jamie with hair.... long time ago
 

Attachment 1: Jamie.jpg
Jamie.jpg
  12163   Thu Jun 9 18:54:40 2016 AakashUpdateGeneralAbout Acromag | SURF 2016

Today I tried to setup Acromag Busworks card. I was able to calibrate and test it over USB but I couldn't test it over ethernet. I'll utilize a few hours tomorrow to test it over ethernet and see if I can make it work. I have also found a few RTDs which I want to use for temperature sensing via four probe method. So, tomorrow I'll get these RTD details revived by Gautam and Steve.

I was wondering if we have a basic DAQ card with maybe 4 channels which is simple to setup like NI DAQ cards.

  12164   Thu Jun 9 19:08:58 2016 VarunUpdateElectronicsAnti-Aliasing Filter update

Eric gave me a psd plot of a signal which would be the input of a channel of the AA filter. the Nyquist freq. is about 32.8kHz.

Following are plots depicting the ratio of the aliased downconverted signal and the signal below 32.8 kHz. The first plot is for (to-be) aliased signal frequencies from 32.8 to 65.5k, and the second plot is for (to-be) aliased signals from 65.5k to 98.3k. In case of the first plot, the 36kHz peak will alias to 29kHz, and is about 30 times (29.5dB) greater than the signal there. Hence, the filter should give about 70dB attenuation there. Since this attenuation is not required by most other frequencies up to 65.5k, an option could be to use a notch filter to remove the frequency peak at 36k, and put a requirement of 45-50 dB attenuation on other frequencies.

In case of the second plot, the frequencies between 90 to 100k again need to be attenuated by more than 70 dB. However, if there is a -20dB/decade slope in stop band, we already have about 10 dB attenuation here as compared to around 32k.

The X axis of both plots is in Hz.

Attachment 1: 32to65.jpg
32to65.jpg
Attachment 2: 65to98.png
65to98.png
  12165   Fri Jun 10 09:52:51 2016 SteveUpdateSUS EQ 5.2 mag Borego Spring

EQ  5.2 mag at Jun 10, 8:04 am UTC, Borego Spring, CA  ~150 mi away.........no obvoius damage, damping restored, MC is locking, arms are flashing

 

Attachment 1: 5.2mBoregoSpring.png
5.2mBoregoSpring.png
Attachment 2: eqBSs.png
eqBSs.png
  12168   Fri Jun 10 16:19:03 2016 ericqUpdateSUSETMX watch

ETMX has been jumping around again lately. Just now, I zeroed the ETMX alignment offsets in the SUS model, and centered the ETMX oplev spot via slow machine sliders. OSEM damping is on, oplev damping is off. Let's see how it moves around in the next day or so. 

GPS: 1149635923 

UTC: Jun 10 2016 23:18:26

  12169   Fri Jun 10 18:16:59 2016 varunUpdatePSLRealignment of pre mode cleaner

The mode cleaner was misaligned probably due to the earthquake (the drop in the MC transmitted value slightly after utc 7:38:52 as seen in the second plot). The plots show PMC transmitted and MC sum signals from 10th june 07:10:08 UTC over a duration of 17 hrs. The PMC was realigned at about 4-4:15 pm today by rana. This can be seen in the first plot.

Attachment 1: pmctrans_mcsum_signals.png
pmctrans_mcsum_signals.png
  12170   Mon Jun 13 09:08:17 2016 SteveUpdatePSLPMC slow drift

The PMC transmission slow degration or it's input beam is not stable.

 

Attachment 1: PMCslowDrift.png
PMCslowDrift.png
  12171   Mon Jun 13 10:01:58 2016 SteveUpdateSUSETMX jumps

 

Quote:

ETMX has been jumping around again lately. Just now, I zeroed the ETMX alignment offsets in the SUS model, and centered the ETMX oplev spot via slow machine sliders. OSEM damping is on, oplev damping is off. Let's see how it moves around in the next day or so. 

GPS: 1149635923 

UTC: Jun 10 2016 23:18:26

 

Attachment 1: noDamping24hrs.png
noDamping24hrs.png
Attachment 2: ETMXjumps.png
ETMXjumps.png
  12172   Mon Jun 13 19:30:58 2016 AakashUpdateGeneralEPICS Installation | SURF 2016

About acquiring data: Initially I couldn't start with proper Acromag setup as the Raspberry pi had a faulty SD card slot. Then Gautam gave me a working pi on which I tried to install EPICS. I spent quite a time today but couldn't setup acromag over ethernet.  But, it would be great if we have a USB DAQ card. I have found a good one here http://www.mccdaq.com/PDFs/specs/USB-200-Series-data.pdf It costs around 106$ including shipping (It comes with some free softwares for acquiring data) . Also, I know an another python based 12bit DAQ card (with an inbuilt constant current source) which is made by IUAC, Delhi and more information can be found here http://www.iuac.res.in/~elab/expeyes/Documents/eyesj-progman.pdf  It costs around 60$ including shipping.

About temperature sensing: The RTD which I found on Omega's list is having a temperature resolution of 0.1 deg C. I have also asked them for the one with good resolution. Also according to their reply, they have not performed any noise characteristics study for those RTDs.

 

  12173   Mon Jun 13 20:01:30 2016 varunUpdateCDSDAFI GUI update

Summary: I am implementing digital audio filtering on various interferometer signals in order to listen to the processed audio which will help in characterizing and noise reduction in the interferometer. following is a summary of the gui i have made towards a general purpose DAF module linked to the LSC. 

Details:  attachment 1 shows the top level overview of the daf module.

The "INPUTS" button shown redirects to the medm screen shown in attachment 2, which is a collection of inputs going into the module.

Each of the buttons shown in "C1DAFI_INPUTS.png" is further linked to various i/o boxes like adc1, adc2, lsc signal and exitation. An example is shown in attachment 3. This is the specific I/O box for the LSC signal.

The field labelled "INPUT_MTRX" is linked to a matrix which routes these 4 inputs to various DSP blocks. Similarly, the "OUTPUT_MTRX" tab is useful for choosing which output goes to the speaker. 

Time and computational load monitoring is done in the "GDS_TP" tab which links to the medm screen shown in attachment 4.

Currently the AGC is successfully implemented as one of the DSP block. The details of the AGC implementation were given in a previous elog: https://nodus.ligo.caltech.edu:8081/40m/12159

I need to make a few changes to the code for Frequency Shifting and Whitening before uploading them on the FE. I will put the details soon.

Some more things that I think need to be added: 

1) "Enable" buttons for each of the DSP blocks.

2) Labels for each of the matrix elements.

3) Further headers and other description for each of the tabs 

Attachment 1: C1DAF_OVERVIEW.png
C1DAF_OVERVIEW.png
Attachment 2: C1DAF_INPUTS.png
C1DAF_INPUTS.png
Attachment 3: C1DAF_LSC.png
C1DAF_LSC.png
Attachment 4: MONITOR.png
MONITOR.png
  12174   Tue Jun 14 10:13:34 2016 SteveUpdateVACtemporary N2 supply line

The drill room floor will be retiled Thursday, June 16. Temporary nitrogen line set up will allow emptying the hole area.

 

Ifo room entry will be through control room.

 

Attachment 1: afterN2work.png
afterN2work.png
  12176   Tue Jun 14 11:52:08 2016 JohannesUpdateGeneralEPICS Installation | SURF 2016

We generally want to keep the configuration of the 40m close to that of the LIGO sites, which is why we chose BusWorks, and it is also being established as a standard in other labs on campus. Of course any suitable DAQ system can do the job, but to stay relevant we generally try to avoid patchwork solutions when possible. Did you follow Aidan's instructions to the book? I haven't set up a system myself, yet, so I cannot say how difficult this is. If it just won't work with the Raspberry Pi, you could still try using a traditional computer.

Alternatively, following Jamie's suggestions, I'm currently looking into using python for the modbus communications (there seem to be at least a few python packages that can do this), which would reportedly make the interfacing and integration a lot easier. I'll let you know when I make any progress on this.

Quote:

About acquiring data: Initially I couldn't start with proper Acromag setup as the Raspberry pi had a faulty SD card slot. Then Gautam gave me a working pi on which I tried to install EPICS. I spent quite a time today but couldn't setup acromag over ethernet.  But, it would be great if we have a USB DAQ card. I have found a good one here http://www.mccdaq.com/PDFs/specs/USB-200-Series-data.pdf It costs around 106$ including shipping (It comes with some free softwares for acquiring data) . Also, I know an another python based 12bit DAQ card (with an inbuilt constant current source) which is made by IUAC, Delhi and more information can be found here http://www.iuac.res.in/~elab/expeyes/Documents/eyesj-progman.pdf  It costs around 60$ including shipping.

About temperature sensing: The RTD which I found on Omega's list is having a temperature resolution of 0.1 deg C. I have also asked them for the one with good resolution. Also according to their reply, they have not performed any noise characteristics study for those RTDs.

 

 

  12177   Tue Jun 14 15:55:17 2016 ericqUpdateSUSETMX watch

Within two hours, it was already all over the place. 

It has been Decided: we will assemble a suspension with the spare ETM optic with the current-generation standoff for installation ASAP. I.e. no new custom parts. We will continue pursuing the new standoff design, but we need our interferometer back.

  12178   Tue Jun 14 16:53:16 2016 ranaUpdateSUSETMX watch

What about ETMY? and are these really microradians or just some made up cal?

  12179   Tue Jun 14 19:37:40 2016 jamieUpdateCDSOvernight daqd test underway

I'm running another overnight test with new daqd software on fb1.  The normal daqd process on fb has been shutdown, and the front ends are sending their signals to fb1.

fb1 is running separate data concentrator (dc) and  frame writer (fw) processes, to see if this is a more stable configuration than the all-in-one framebuilder (fb) that we have been trying to run with.  I'll report on the test tomorrow.

  12180   Tue Jun 14 20:10:19 2016 varunUpdateCDSDAFI GUI update

I have added Enable buttons for each of the DSP blocks, and labels for the matrix elements. The input matrix takes inputs from each of the 4 channels: ADC1, ADC2, LSC and EXC, and routes them to the audio processing blocks (attachment 2). The output matrix (attachment 3) takes the outputs of the various DSP blocks and routes them to the output and then to the speakers. 

Attachment 1: C1DAF_OVERVIEW.png
C1DAF_OVERVIEW.png
Attachment 2: input_matrix.png
input_matrix.png
Attachment 3: output_matrix.png
output_matrix.png
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