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ID Date Authorup Type Category Subject
  1560   Fri May 8 02:08:59 2009 peteUpdateLockinglock stretches

locks last for about an hour.  this was true last night as well (see "arm power curve" entries).   the second lock shown here evolves differently for unknown reasons.  the jumps in the arm powers of the first lock are due to turning on DC readout.  length-to-angle needs tuning.



Attachment 1: powers_oplev.pdf
  1565   Fri May 8 15:40:44 2009 peteUpdateLockingprogressively weaker locks

the align script was run after the third lock here.  it would have been interesting to see the arm powers in a 4th lock 

Attachment 1: powers_3lock.pdf
  1578   Tue May 12 17:26:56 2009 peteUpdateoplevsetmy oplev quad was bad

Pete, Rob

After looking at some oplev noise spectra in DTT, we discovered that the ETMY quad (serial number 115)  was noisy.  Particularly, in the XX_OUT and XX_IN1 channels, quadrants 2 (by a bit more than an order of magnitude over the ETMX ref) and 4 (by a bit less than an order of mag).  We went out and looked at the signals coming out of the oplev interface board; again, channels 2 and 4 were noise compared to 1 and 3 by about these same amounts.  I popped in the ETMX quad and everything looked fine.  I put the ETMX quad back at ETMX, and popped in Steve's scatterometer quad (serial number 121 or possibly 151, it's not terribly legible), and it looks fine.  We zeroed via the offsets in the control room, and I went out and centered both the ETMX and ETMY quads. 

Attached is a plot.  The reference curves are with the faulty quad (115).  The others are with the 121.


Attachment 1: bad_oplev_quad.pdf
  1580   Wed May 13 03:05:13 2009 peteUpdateoplevsetmy oplev quad was bad


Pete, Rob

After looking at some oplev noise spectra in DTT, we discovered that the ETMY quad (serial number 115)  was noisy.  Particularly, in the XX_OUT and XX_IN1 channels, quadrants 2 (by a bit more than an order of magnitude over the ETMX ref) and 4 (by a bit less than an order of mag).  We went out and looked at the signals coming out of the oplev interface board; again, channels 2 and 4 were noise compared to 1 and 3 by about these same amounts.  I popped in the ETMX quad and everything looked fine.  I put the ETMX quad back at ETMX, and popped in Steve's scatterometer quad (serial number 121 or possibly 151, it's not terribly legible), and it looks fine.  We zeroed via the offsets in the control room, and I went out and centered both the ETMX and ETMY quads. 

Attached is a plot.  The reference curves are with the faulty quad (115).  The others are with the 121.


 I adjusted the ETMY quad gains up by a factor of 10 so that the SUM is similar to what it was before.

  1585   Thu May 14 02:36:05 2009 peteUpdateLockingunstable IFO

It seems that the MC3 problem is intermittent (one-day trend attached).  I tried to take advantage of a "clean MC3" night, but the watch script would usually fail at the transition to DC CARM and DARM.  It got past this twice and then failed later, during powering up.   I need to check the handoff.


Attachment 1: mc3.jpg
  1587   Thu May 14 16:07:20 2009 peteSummarySUSChannel Hopping: That ancient enemy (MC problems)


The MC side problem could also be the side tramp unit problem. Set the tramp to 0 and see if that helps.

This started around April 23, around the time that TP1 failed and we switched to the cryopump, and also when there was a mag 4 earthquake in LA. My money's on the EQ. But I don't know how.

I wonder if this is still a problem. It has been quiet for a day now. I've attached a day-long trend. Let's see what happens.
Attachment 1: mc3_5days.jpg
  1588   Fri May 15 00:02:34 2009 peteUpdateSUSETMX coils look OK

I checked the four rear coils on ETMX by exciting XXCOIL_EXC channel in DTT with amplitude 1000@ 500 Hz and observing the oplev PERROR and YERROR channels.  Each coil showed a clear signal in PERROR, about 2e-6 cts.  Anyway, the coils passed this test.


  1610   Wed May 20 01:41:19 2009 peteUpdateVACcryopump probably not it

I found some neat signal analysis software for my mac (http://www.faberacoustical.com/products/), and took a spectrum of the ambient noise coming from the cryopump.  The two main noise peaks from that bad boy were nowhere near 3.7 kHz.

  1616   Thu May 21 18:05:03 2009 peteUpdateSUSETMX coils look OK


I checked the four rear coils on ETMX by exciting XXCOIL_EXC channel in DTT with amplitude 1000@ 500 Hz and observing the oplev PERROR and YERROR channels.  Each coil showed a clear signal in PERROR, about 2e-6 cts.  Anyway, the coils passed this test.


 I also made xfer fctns of the 4 piston coils on ETMY and ETMX with OL_PIT.  (I looked at all 4 even though the attached plot only shows three.)  So it looks ike the coils are OK.

Attachment 1: etmx_etmy_coils.pdf
  1620   Fri May 22 01:27:14 2009 peteUpdateSUS200 days of MC3 side

Looks like something went nuts in late April.  We have yet to try a hard reboot.

Attachment 1: mc3_side_200days.png
  1641   Tue Jun 2 02:28:58 2009 peteUpdateLockingDD handoff work

alberto, pete


We worked on tuning the DD handoff tonight.  We checked the DD PD alignments and they looked fine.  First I tuned the 3 demod phases to minimize offsets.  Then I noticed that the post-handoff MICH xfer function needed an increase in gain to look like the pre-handoff xfer function (which has a UGF of about 25 Hz).  I increased the MICH PD9_Q gain from 2 to 7 in the input matrix.   But, the handoff to PRC still failed, so tomorrow we will try to find out why.

In the plot, ref0 is before MICH handoff, and ref1 is after MICH handoff.  There is also a PRC trace (before PRC handooff).



Attachment 1: mich_dd.pdf
mich_dd.pdf mich_dd.pdf
  1643   Tue Jun 2 23:53:12 2009 peteDAQComputersreset c1susvme1

rob, alberto, rana, pete

we reset this computer, which was out of sync (16384 in the FE_SYNC field instead of 0)

  1645   Wed Jun 3 03:22:16 2009 peteUpdateLockingDD handoff

Rana, Alberto, Pete

We have the DD handoff nominally working.  Sometimes, increasing the SRC gain at the end makes MICH get unstable.  This could be due to a non-diagonal term in the matrix, or possibly because the DRM locks in a funky mode sometimes. 

To get the DD handoff working, first we tuned demod phases in order to zero the offsets in the PD signals handed-off-to.  Based on transer function measurements, I set the PRC PD6_I element to 0.1, and set the PD8_I signal to 0, since it didn't seem to be contributing much.  We also commented out the MICH gain increase at the end of the DD_handoff script.

It could still be more stable, but it seems to work most of the time.



  1652   Thu Jun 4 16:54:19 2009 peteUpdateLockingdaytime DD handoff

I played with the DD handoff during the day.  The DRM dark port was flickering like a candle flame in Dracula's castle.  The demod offsets for the handoff signals looked fine.  After MICH handoff, the MICH_CTRL started to get unstable at some low frequency, maybe 3 Hz (I didn't measure).  So I increased the MICH gain from 0.1 to 0.17 and it settled down.  PRC and SRC went fine.  Then the DD_handoff script raised the MICH gain to 0.7, and an instability started to grow in MICH_CTRL (at some higher frequency).  I decreased the MICH gain from 0.7 to 0.5, and it settled down and stayed stable.

  1653   Thu Jun 4 23:39:23 2009 peteUpdatePEM5 days, 20 days of accelerometers

Looks like yesterday was particularly noisy.  It's unclear to me why diurnal variation much more visible in MC1_Y, and why the floor wanders.


The first plot shows 5 days.  The second plot shows 20 days.

Attachment 1: acc_5day.png
Attachment 2: acc_20days.png
  1658   Fri Jun 5 17:22:55 2009 peteUpdateLockingdaytime locking

After fixing the tp problem, I tried locking again.  Grabbing and DD handoff, no problem.  Died earlier than last night, handing off CARM to REFL_DC, around arm power of 4 or so.  Seems to happen after turning off the moving zero, Rob says it might be touchy in daytime.

  1679   Tue Jun 16 16:10:01 2009 peteUpdateLockinginput matrix experiments

Last night Rob ran senseDRM and loadDRMImatrixData and came up with the following for the input matrix:

tdswrite C1:LSC-ITMTRX_b2 0.065778 \
C1:LSC-ITMTRX_d2 2.2709 \
C1:LSC-ITMTRX_f2 2.9361 \
C1:LSC-ITMTRX_122 0.42826 \
C1:LSC-ITMTRX_b3 -0.064839 \
C1:LSC-ITMTRX_d3 -0.016913 \
C1:LSC-ITMTRX_f3 -0.021576 \
C1:LSC-ITMTRX_123 -0.0025243 \
C1:LSC-ITMTRX_b5 0.3719 \
C1:LSC-ITMTRX_d5 1.3109 \
C1:LSC-ITMTRX_f5 -0.16412 \
C1:LSC-ITMTRX_125 0.39574 \
C1:LSC-ITMTRX_33 0 \
C1:LSC-ITMTRX_42 0 \

Today, I reran these and got the following, and DD_handoff remained happy:

tdswrite C1:LSC-ITMTRX_b2 -0.10329 \
C1:LSC-ITMTRX_d2 2.0344 \
C1:LSC-ITMTRX_f2 3.2804 \
C1:LSC-ITMTRX_122 0.22516 \
C1:LSC-ITMTRX_b3 -0.076292 \
C1:LSC-ITMTRX_d3 -0.014603 \
C1:LSC-ITMTRX_f3 -0.12101 \
C1:LSC-ITMTRX_123 0.0054128 \
C1:LSC-ITMTRX_b5 0.33521 \
C1:LSC-ITMTRX_d5 1.1425 \
C1:LSC-ITMTRX_f5 -0.32759 \
C1:LSC-ITMTRX_125 0.25877 \
C1:LSC-ITMTRX_33 0 \
C1:LSC-ITMTRX_42 0 \

I wanted to remeasure with the canonical output matrix (-0.7 from MICH to PRM and 0.7 from MICH to SRM), but the DRM freaked out when MICH to PRM went below -0.3.

  1769   Tue Jul 21 17:01:18 2009 peteDAQDAQtemp channel PEM-PETER_FE

I added a temporary channel, to input 9 on the PEM ADCU.    Beware the 30, 31, and 32 inputs.  I tried 32 and it only gave noise.



  1781   Wed Jul 22 20:11:26 2009 peteUpdateComputersRCG front end

I compiled and ran a simple (i.e. empty) front end controller on scipe12 at wilson house.  I hooked a signal into the ADC and watched it in the auto-generated medm screens. 

There were a couple of gotchas:

1. Add an entry SYS to the file /etc/rc.local, to the /etc/setup_shmem.rtl line, where the system file is SYS.mdl.

2. If necessary, do a BURT restore.  Or in the case of a mockup set the BURT Restore bit (in SYS_GDS_TP.adl) to 1.


  1805   Wed Jul 29 12:14:40 2009 peteUpdateComputersRCG work

Koji, Pete 

Yesterday, Jay brought over the IO box for megatron, and got it working.  We plan to firewall megatron this afternoon, with the help of Jay and Alex, so we can set up GDS there and play without worrying about breaking things.  In the meantime, we went to Wilson House to get some breakout boards so we can take transfer functions with the 785, for an ETMX controller.  We put in a sine wave, and all looks good on the auto-generated epics screens, with an "empty" system (no filters on). Next we'll load in filters and take transfer functions.

Unfortunately we promised to return the breakout boards by 1pm today.  This is because, according to denizens of Wilson House, Osamu "borrowed" all their breakout boards and these were the last two!  If we can't locate Osamu's cache, they expect to have more in a day or two.

Here is the transfer function of the through filter working at 16KHz sampling. It looks fine except for the fact that the dc gain is ~0.8. Koji is going to characterize the digital down sampling filter in order to try to compare with the generated code and the filter coefficients.

Attachment 1: TF090729_1.png
Attachment 2: TF090729_1.png
  1819   Mon Aug 3 13:47:42 2009 peteUpdateComputersRCG work

Alex has firewalled megatron.  We have started a framebuilder there and added testpoints.  Now it is possible to take transfer functions with the shared memory MDC+MDP sandbox system.  I have also copied filters into MDC (the controller) and made a really ugly medm master screen for the system, which I will show to no one.

  1826   Tue Aug 4 13:40:17 2009 peteUpdateComputersRCG work - rate

Koji, Pete


Yesterday we found that the channel C1:MDP-POS_EXC looked distorted and had what appeared to be doubled frequency componenets, in the dataviewer.  This was because the dcu_rate in the file /caltech/target/fb/daqdrc was set to 16K while the adl file was set to 32K.  When daqdrc was corrected it was fixed.  I am going to recompile and run all these models at 16K.  Once the 40 m moves over to the new front end system, we may find it advantageous to take advantage of the faster speeds, but maybe it's a good idea to get everything working at 16K first.

  1829   Tue Aug 4 17:51:25 2009 peteUpdateComputersRCG work

Koji, Peter


We put a simple pendulum into the MDP model, and everything communicates.  We're still having some kind of TP or daq problem, so we're still in debugging mode.  We went back to 32K in the .adl's, and when driving MDP,  the MDC-ETMX_POS_OUT is nasty, it follows the sine wave envelope but goes to zero 16 times per second.


The breakout boards have arrived.  The plan is to fix this daq problem, then demonstrate the model MDC/MDP system.  Then we'll switch to the "external" system (called SAM) and match control TF to the model.  Then we'd like to hook up ETMX, and run the system isolated from the rest of the IFO.  Finally we'd like to tie it into the IFO using reflective memory.

  1839   Wed Aug 5 17:41:54 2009 peteUpdateComputersRCG work - daq fixed

The daq on megatron was nuts.  Alex and I discovered that there was no gds installation for site_letter=C (i.e. Caltech) so the default M was being used (for MIT).  Apparently we are the first Caltech installation.  We added the appropriate line to the RCG Makefile and recompiled and reinstalled (at 16K).  Now DV looks good on MDP and MDC, and I made a transfer function that replicates  bounce-roll filter.  So DTT works too.

  1856   Fri Aug 7 16:00:17 2009 peteUpdateComputersRCG work. MDC MDP open loop transfer function

Today I was able to make low frequency transfer function with DTT on megatron.  There seems to have been a timing problem, perhaps Alex fixed it or it is intermittent.

I have attached the open loop transfer function for the un-optimized system, which is at least stable to step impulses with the current filters and gains.  The next step is to optimize, transfer this knowledge to the ADC/DAC version, and hook it up to isolated ETMX.

Attachment 1: tf_au_natural.pdf
tf_au_natural.pdf tf_au_natural.pdf
  1879   Mon Aug 10 17:36:32 2009 peteUpdateComputersRCG work. PIT, YAW, POS in MDP/MDC system

I've added the PIT and YAW dofs to the MDC and MDP systems.  The pendula frequencies in MDP are 0.8, 0.5, 0.6 Hz for POS, PIT, and YAW respectively.  The three dofs are linear and uncoupled, and stable, but there is no modeled noise in the system (yet) and some gains may need bumping up in the presence of noise.  The MDC filters are identical for each dof (3:0.0 and Cheby). The PIT and YAW transfer functions look pretty much like the one Rana recently took of POS, but of course with the different pendulum frequencies.  I've attached one for YAW.

Attachment 1: mdcmdpyaw.jpg
  1881   Mon Aug 10 17:49:10 2009 peteUpdateComputersRCG work - plans

Pete, Koji


We discussed a preliminary game plan for this project.  The thing I really want to see is an ETMX RCG controller hooked into the existing frontend via reflective memory, and the 40 m behaving normally with this hybrid system, and my list is geared toward this.  I suspect the list may cause controversy.

+ copy the MDC filters into SAM, and make sure everything looks good there with DTT and SR785.

+ get interface / wiring boards from Wilson House, to go between megatron and the analog ETMX system

+ test tying the ETMX pendulum and bare-bones SAM together (use existing watchdogs, and "bare-bones" needs defining)

+ work some reflective memory magic and create the hybrid frontend


In parallel with the above, the following should also happen:

+ MEDM screen design

+ add non-linear bits to the ETMX MDP/MDC model system

+ make game plan for the rest of the RCG frontend

  2182   Thu Nov 5 16:30:56 2009 peteUpdateComputersmoving megatron

 Joe and I moved megatron and its associated IO chassis from 1Y3 to 1Y9, in preparations for RCG tests at ETMY.

  2198   Fri Nov 6 18:52:09 2009 peteUpdateComputersRCG ETMY plan

  Koji, Joe, and I are planning to try controlling the ETMY, on Monday or Tuesday.  Our plan is to try to do this with megatron out of the RFM loop.   The RCG system includes pos, pit, yaw, side, and oplevs.  I will use matrix elements as currently assigned (i.e. not the ideal case of +1 and -1 everywhere).   I will also match channel names to the old channels.   We could put buttons on the medm screen to control the analog DW by hand.  

This assumes we can get megatron happy again, after the unhappy RFM card test today.  See Joe's elog immediately before this one.
We first plan to test that the ETMY watchdog can disable the RCG frontend, by using a pos step (before connecting to the suspension).   Hopefully we can make it work without the RFM.  Otherwise I think we'll have to wait for a working RFM card.
We plan to disable the other optics.  We will disable ETMY, take down the ETMY frontend, switch the cables, and start up the new RCG system.  If output looks reasonable we will enable the ETMY via the watchdog.   Then I suppose we can put in some small steps via the RCG controller and see if it damps.  
Afterwards, we plan to switch everything back.
  2233   Wed Nov 11 01:33:52 2009 peteUpdateCDSRCG ETMY code update

 I've added the side coil to the model controller and plant, and the oplev quad to the model controller and plant.  After the megatron wipe, the code now lives in /home/controls/cds/advLigo/src/epics/simLink.  The files are mdc.mdl (controller) and mdp.mdl (plant).  These RCG modules go at 16K with no decimation (no_oversampling=1 in the cdsParameters block) so hopefully will work with the old (16K) timing.

I've loaded many of the filters, there are some eft to do.  These filters are simply copied from the current frontend.  

Next I will port to the SUS module (which talks to the IO chassis).  This means channel names will match with the current system, which will be important when we plug in the RFM.

  2243   Wed Nov 11 20:46:07 2009 peteUpdateCDSRCG ETMY phase I update

The .mdl code for the mdc and mdp development modules is finished.  These modules need more filters, and testing.  Probably the most interesting piece left to do is putting in the gains and filters for the oplev model in mdp.  It might be OK to simply ignore oplevs and first test damping of the real optic without them.   However, it shouldn't be hard to get decent numbers for oplevs, add them to the mdp (plant) module, and make sure the mdc/mdp pair is stable.  In mdp, the oplev path starts with the SUSPIT and SUSYAW signals. Kakeru recently completed calibration of the oplevs from oplev cts to radians:   1403  .  From this work we should find the conversion factors from PIT and YAW to oplev counts, without making any new measurements.  (The measurements wouldn't be hard either, if we can't simply pull numbers from a document.)  These factors can be added to mdp as appropriate gains.

I've also copied mdc to a new module, which I've named "sas" to address fears of channel name collisions in the short term, and replaced the cpu-to-cpu connections with ADC and DAC connections.  sas can be the guy for the phase I ETMY test.  When we're happy with mdc/mdp, we hopefully can take the mdc filter file from chans, replace all the "MDC" strings with "SAS", and use it.

  2293   Wed Nov 18 16:24:25 2009 peteConfigurationSUSETMY suspension conencted to megatron ADC/DAC

/cvs/cds/caltech/target/fb/daqd -c daqdrc

This starts the FB.

Now the dataviewer and DTT work!


0) Now the connection for the ETMY suspension was restored in a usual state. It damps well.

1) I thought it would be nice to have dataviewer and DTT working.
   So far, I could not figure out how to run daqd and tpman.
   - I tried to configure
(via daqconfig)

   - I also looked at
   but I don't understand how it works. The entries have dcuids of 13 and 14 although C1TST has dcuid of 10.
   The file is unmodified.

   I will try it later when I got a help of the experts.

2) Anyway, I went ahead. I tried to excite suspension by putting some offset.

It seems to have no DAC output. I checked the timing signal. It seems that looks wrong clock.

   I looked at DAC output by putting 5000,10000,15000,20000,25000cnt to UL/UR/LR/LL/SD coils.
   I could not find any voltage out of the DAC in any channels.

   Then, I checked the timing signal. This clock seems to have wrong frequency.
   What we are using now is a clock with +/-4V@4MHz. (Differential)
   Maybe 4194304Hz (=2^22Hz)?

   I went to 1Y3 and checked the timing signal for 16K. This was +/-4V@16kHz. (Diffrential)

   The possible solution would be
   - bring a function generator at the end and try to input a single end 4V clock.
   - stretch a cable from 1Y3 to 1Y9. (2pin lemo)


I have connected ETMY sus electronics to megatron ADC/DAC.
We continue this state until 15:00 of today.



  2296   Thu Nov 19 08:53:12 2009 peteFrogsEnvironmentdiesel fumes

 Instead of doing RCG stuff, I went to Millikan to work on data analysis as I couldn't stand the fumes from the construction.  (this morning, 8am) 

  1655   Fri Jun 5 02:59:03 2009 pete, albertoUpdateLockingtdsavg failure in cm_step script

the command

tdsavg 5 C1:LSC-PD4_DC_IN1

was causing grievous woe in the cm_step script.  It turned out to fail intermittently at the command line, as did other LSC channels.  (But non-LSC channels seem to be OK.)  So we power cycled c1lsc (we couldn't ssh).

Then we noticed that computers were out of sync again (several timing fields said 16383 in the C0DAQ_RFMNETWORK screen).  We restarted c1iscey, c1iscex, c1lsc, c1susvme1, and c1susvme2.  The timing fields went back to 0.  But the tdsavg command still  intermittently said "ERROR: LDAQ - SendRequest - bad NDS status: 13".

The channel C1:LSC-SRM_OUT16 seems to work with tdsavg every time.

Let us know if you know how to fix this. 


  1561   Fri May 8 02:39:02 2009 pete, ranaUpdateLockingcrossover

attached plot shows MC_IN1/MC_IN2.  needs work.

This is supposed to be a measurement of the relative gain of the MCL and AO paths in the CM servo. We expect there to

be a more steep slope (ideally 1/f). Somehow the magnitude is very shallow and so the crossover is not stable. Possible

causes? Saturations in the measurement, broken whitening filters, extremely bad delay in the digital system? needs work.


Attachment 1: crossover.pdf
Attachment 2: photo.jpg
  5   Fri Oct 19 16:11:38 2007 pkpOtherOMCOMC PZT response
Sam and I locked the laser to the OMC cavity and looked at the error signal as a function of the voltage applied to the OMC PZT.
Here are two plots showing the response as a function of frequency from 1 kHz to 100 kHz and another high-res response in the region of 4.5 kHz to 10 kHz.
Attachment 1: fullspec.jpg
Attachment 2: 4.5to10.jpg
Attachment 3: 4.5to10.pdf
Attachment 4: fullres.pdf
  8   Mon Oct 22 19:27:14 2007 pkpOtherOMCPZT calibration/ transfer function.
We measured the PZT transfer function by comparing the PZT response of the circuit with the cavity in the loop, with that of the circuit without the cavity in the loop. Basically measure the transfer function of the whole loop with the laser/PZT and Op-amps in it. Then take another measurement of the transfer function of everything else besides the PZT and from both these functions, we can calculate the PZT response.

The calibration was done by using the error signal response to a triangular wave of volts applied to the PZT. A measurement of the slope of the error signal , which has three zero-crossings as the cavity sweeps through the sidebands, gives us the Volts/Hz response. In order to derive a frequency calibration of the x axis, we assume that the first zero crossing corresponds to the first side band (-29.5 MHz) and the third one corresponds with the other sideband (+29.5 MHz). And then by using the fact that we know the response of the cavity to a constant frequency shift, we can use the Volts/Hz measurement to calculate the Volts/nm calibration. The slope that was calculated was 3.2e-6 V/Hz and using the fact that the cavity is 1 m in length and the frequency is 1064 nm, we get a calibration of 0.9022 V/nm.

Attachment 1: calib.pdf
Attachment 2: calibpzt2.pdf
Attachment 3: all2.pdf
Attachment 4: noPZT2.pdf
  82   Thu Nov 8 00:55:44 2007 pkpUpdateOMCSuspension tests
[Sam , Pinkesh]

We tried to measure the transfer functions of the 6 degrees of freedom in the OMS SUS. To our chagrin, we found that it was very hard to get the OSEMs to center and get a mean value of around 6000 counts. Somehow the left and top OSEMs were coupled and we tried to see if any of the OSEMs/suspension parts were touching each other. But there is still a significant coupling between the various OSEMs. In theory, the only OSEMS that are supposed to couple are [SIDE] , [LEFT, RIGHT] , [TOP1, TOP2 , TOP3] , since the motion along these 3 sets is orthogonal to the other sets. Thus an excitation along any one OSEM in a set should only couple with another OSEM in the same same set and not with the others. The graphs below were obtained by driving all the OSEMS one by one at 7 Hz and at 500 counts ( I still have to figure out how much that is in units of length). These graphs show that there is some sort of contact somewhere. I cant locate any physical contact at this point, although TOP2 is suspicious and we moved it a bit, but it seems to be hanging free now. This can also be caused by the stiff wire with the peek on it. This wire is very stiff and it can transmit motion from one degree of freedom to another quite easily. I also have a graph showing the transfer function of the longitudnal degree of freedom. I decided to do this first because it was simple and I had to only deal with SIDE, which seems to be decoupled from the other DOFs. This graph is similar to one Norna has for the longitudnal DOF transfer function, with the addition of a peak around 1.8 Hz. This I reckon could very be due to the wire, although it is hard to claim for certain. I am going to stop the measurement at this time and start a fresh high resolution spectrum and leave it running over night.

There is an extra peak in the high res spectrum that is disturbing.
Attachment 1: shakeleft.pdf
Attachment 2: shakeright.pdf
Attachment 3: shakeside.pdf
Attachment 4: shaketop1.pdf
Attachment 5: shaketop2.pdf
Attachment 6: shaketop3.pdf
Attachment 7: LongTransfer.pdf
LongTransfer.pdf LongTransfer.pdf LongTransfer.pdf
Attachment 8: Shakeleft7Nov2007_2.pdf
Attachment 9: Shakeleft7Nov2007_2.png
  87   Fri Nov 9 00:23:12 2007 pkpUpdateOMCX and Z resonances
I got a couple of resonance plots going for now. I am still having trouble getting the Y measurement going for some reason. I will investigate that tommorow. But for tonight and tommorow morning, here is some food for thought. I have attached the X and Z transfer functions below. I compared them to Norna's plots - so just writing out what I was thinking -

Keep in mind that these arent high res scans and have been inconviniently stopped at 0.5 Hz Frown.

Z case --

I see two small resonances and two large ones - the large ones are at 5.5 Hz and 0.55 Hz and the small ones at 9 Hz and 2 Hz respectively. In Norna's resonances, these features arent present. Secondly, the two large peaks in Norna's measurement are at 4.5 Hz and just above 1 Hz. Which was kind of expected, since we shortened the wires a bit, so one of the resonances moved up and I suppose that the other one moved down for the same reason.

X case --

Only one broad peak at about 3 Hz is seen here, whereas in Norna's measurement, there were two large peaks and one dip at 0.75 Hz and 2.5 Hz. I suspect that the lower peak has shifted lower than what I scanned to here and a high res scan going upto 0.2 Hz is taking place overnight. So we will have to wait and watch.

Pitch Roll and Yaw can wait for the morning.
Attachment 1: Xtransferfunc.pdf
Xtransferfunc.pdf Xtransferfunc.pdf Xtransferfunc.pdf
Attachment 2: Ztransferfunc.pdf
Ztransferfunc.pdf Ztransferfunc.pdf Ztransferfunc.pdf
  93   Mon Nov 12 10:53:58 2007 pkpUpdateOMCVertical Transfer functions
[Norna Sam Pinkesh]

These plots were created by injected white noise into the OSEMs and reading out the response of the shadow sensors ( taking the power spectrum). We suspect that some of the additional structure is due to the wires.
Attachment 1: VerticalTrans.pdf
VerticalTrans.pdf VerticalTrans.pdf VerticalTrans.pdf VerticalTrans.pdf
  102   Wed Nov 14 16:54:54 2007 pkpUpdateOMCMuch better looking vertical transfer functions
[Norna Pinkesh]

So after Chub did his wonderful mini-surgery and removed the peek from the cables and after Norna and I aligned the whole apparatus, the following are the peaks that we see.
It almost exactly matches Norna's simulations and some of the extra peaks are possibly due to us exciting the Roll/longitudnal/yaw and pitch motions. The roll resonance is esp prominent.

We also took another plot with one of the wires removed and will wait on Chub before we remove another wire.
Attachment 1: VerticalTransPreampwireremovedNov142007.pdf
VerticalTransPreampwireremovedNov142007.pdf VerticalTransPreampwireremovedNov142007.pdf VerticalTransPreampwireremovedNov142007.pdf VerticalTransPreampwireremovedNov142007.pdf
Attachment 2: VerticalTranswiresclampedNov142007.pdf
VerticalTranswiresclampedNov142007.pdf VerticalTranswiresclampedNov142007.pdf VerticalTranswiresclampedNov142007.pdf VerticalTranswiresclampedNov142007.pdf
  105   Thu Nov 15 17:09:37 2007 pkpUpdateOMCVertical Transfer functions with no cables attached.
[Norna Pinkesh]

The cables connecting all the electronics ( DCPDs, QPDs etc) have been removed to test for the vertical transfer function. Now the cables are sitting on the OMC bench and it was realigned.
Attachment 1: VerticaltransferfuncnocablesattachedNov152007.pdf
VerticaltransferfuncnocablesattachedNov152007.pdf VerticaltransferfuncnocablesattachedNov152007.pdf VerticaltransferfuncnocablesattachedNov152007.pdf VerticaltransferfuncnocablesattachedNov152007.pdf
  215   Thu Dec 27 12:12:02 2007 pkpUpdate Update on GigE Camera
So I finally got the linux software to compile on mafalda. I got the software to dump all the information regarding the camera onto a file. I tried to take a tiff snap and came up empty. So I looked at the configuration file and realized that the camera thinks that the frame-rate is a nan. Am reading up the manual to fix the frame-rate manually and then will attempt to take another snap.

All the files are in a folder called Prosilica in /home/controls/ on mafalda. All the executables are in /home/controls/Prosilica/bin-pc/x86/* . On another note, I am looking for a name for the camera. Any suggestions are welcome.
  218   Sun Dec 30 02:36:35 2007 pkpUpdateGeneralAnother update
So I followed suggestions 1 and 3 so far and have started writing up what all needs to be done in order to compile and use the camera. I wrote a program to ping the camera and get its properties and am working on a program to get an image. The reason why I want to write my own programs to do this, is that it will be easier to reuse and also to compile/use in the first place. The programs currently rest in /cvs/cds/caltech/target/Prosilica/ . Unfortunately I will be away for the next couple of days and will have another update on the 2nd.
  236   Fri Jan 11 17:01:51 2008 pkpUpdateCamerasGigE again
So, here I detail all the efforts on the GigE so far

(1) The GiGE camera requires a minimum of 9 kb packet size, which is not available on mafalda or on my laptop ( both of which run Ubuntu and the Camera programs compile there). The programs which require smaller sizes work perfectly fine on these machines. I tried to statically compile the files on these machines so that I could then port them to the other machines. But that fails because the static libraries given by the company dont work.

(2) On Linux2, which lets me set a packet size as high as 9 Kb, it doesnt compile because of a GLIBC error. I tried updating the glibc and it tells me that the version already existing is the latest ( which it clearly is not). So I tried to uninstall GLIBC and reinstall it, but it wont let me uninstall (it == rpm) glibc, since there are a lot of dependencies. A dead end in essence.

Steps being taken

(1) Locally installing the whole library suites on linux2. Essentially install another version of gcc and g++ and see if that helps.
(2) IF this doesnt work, then the only course of action I can take is to cannibalize linux2's GigE card and put it on mafalda. ( I need permission for this Smile ).

Once again any suggestions welcome.
  13874   Mon May 21 17:36:00 2018 poojaUpdateCamerasGigE camera image of ETMX

Today Steve and I tried to to capture the image of scattering of light by dust particles on the surface of ETMX using GigE camera. The image ( at gain =100, exposure time = 125000) obtained has been attached. Unlike the previous images, a creepy shape of bright spots was seen. Gautam helped us lock infrared light and see the image. A similar less intense shape was seen. This may be because of the dust on the lens.

Attachment 1: Image__2018-05-21__17-34-15_125k100g.tiff
  13909   Fri Jun 1 19:25:11 2018 poojaUpdateCamerasSynchronizing video data with the applied motion to the mirror

Aim: To synchronize data from the captured video and the signal applied to ETMX

In order to correlate the intensity fluctuations of the scattered light with the motion of the test mass, we are planning to use the technique of neural network. For this, we need a synchronised video of scattered light with the signal applied to the test mass. Gautam helped me capture 60sec video of scattering of infrared laser light after ETMX was dithered in PITCH at ~0.2Hz..

I developed a python program to capture the video and convert it into a time series of the sum of pixel values in each frame using OpenCV to see the variation. Initially we had tried the same with green laser light and signal of approximately 11.12Hz. But in order to see the variation clearly, we repeated with a lower frequency signal after locking IR laser today. I have attached the plots that we got below. The first graph gives the intensity fluctuations from the video. The third and fourth graphs are that of transmitted light and the signal applied to ETMX to shake it. Since the video captured using the camera was very noisy and intensity fluctuations in the scattered light had twice the frequency of the signal applied, we captured a video after turning off the laser. The second plot gives the background noise probably from the camera. Since camera noise is very high, it may not be possible to train this data set in neural network.

Since the videos captured consume a lot of memory I haven't uploaded it here. I have uploaded the python code 'sync_plots.py' in github (https://github.com/CaltechExperimentalGravity/GigEcamera/tree/master/Pooja%20Sekhar/PythonCode).


Attachment 1: camera_mirror_motion_plots.pdf
  13928   Thu Jun 7 20:19:53 2018 poojaUpdate  

Just to inform, I'm working in optimus to develop python code to train the neural network since it requires a lot of memory.

  13937   Sun Jun 10 15:04:33 2018 poojaUpdateCamerasDeveloping neural network

Aim: To develop a neural network in order to correlate the intensity fluctuations in the scattered light to the angular motion of the test mass. A block diagram of the technique employed is given in Attachment 1.

I have used Keras to implement supervised learning using neural network (NN). Initially I had developed a python code that converts a video (59 sec) of scattered light, after an excitation (sine wave of frequency 0.2 Hz) is applied to ETMX pitch, to image frames (of size 480*720)  and stores the 2D pixel values of 1791 images frames captured into an hdf5 file. This array of shape (1791,36500) is given as an input to the neural network. I have tried to implement regular NN only, not convolution or recurrent NN. I have used sequential model in Keras to do this. I have tried with various number of dense layers and varied the number of nodes in each layer. I got test accuracy of approximately 7% using the following network. There are two dense layers, first one with 750 nodes with a dropout of 0.1 ( 10% of the nodes not used) and second one with 500 nodes. To add nonlinearity to the network, both the layers are given an activation function of tanh. The output layer has 1 node and expects an output of shape (1791,1). This model has been compiled with a loss function of categorical crossentropy, optimizer = RMSprop. We have used these since they have been mostly used in the image analysis examples. Then the model is trained against the dataset of mirror motion. This has been obtained by sampling the cosine wave fit to the mirror motion so that the shapes of the input and output of NN are consistent. I have used a batch size ( number of samples per gradient update) = 32 and epochs (number of times entire dataset passes through NN) = 20. However, using this we got an accuracy of only 7.6%. 

I think that the above technique gives overfitting since dense layers use all the nodes during training apart from giving a dropout. Also, the beam spot moves in the video. So it may be necessary to use convolution NN to extract the information.

The video file can be accesses from this link https://drive.google.com/file/d/1VbXcPTfC9GH2ttZNWM7Lg0RqD7qiCZuA/view.

Gabriele told us that he had used the beam spot motion to train the neural network. Also he informed that GPUs are necessary for this. So we have to figure out a better way to train the network.  

gautam noon 11Jun: This link explains why the straight-up fully connected NN architecture is ill-suited for the kind of application we have in mind. Discussing with Gabriele, he informed us that training on a GPU machine with 1000 images took a few hours. I'm not sure what the CPU/GPU scaling is for this application, but given that he trained for 10000 epochs, and we see that training for 20 epochs on Optimus already takes ~30minutes, seems like a futile exercise to keep trying on CPU machines.

Attachment 1: nn_block_diag_2.pdf
  13940   Mon Jun 11 17:18:39 2018 poojaUpdateCamerasCCD calibration

Aim: To calibrate CCD of GigE using LED1050E.

The following table shows some of the specifications for LED1050E as given in Thorlabs datasheet.

Specifications Typical maximum ratings
DC forward current (mA)   100
Forward voltage (V) @ 20mA (VF) 1.25 1.55
Forward optical power (mW) 1.6  
Total optical power (mW) 2.5  
Power dissipation (mW)   130

 The circuit diagram is given in Attachment 1.

Considering a power supply voltage Vcc = 15V, current I = 20mA & forward voltage of led VF = 1.25V, resistance in the circuit is calculated as,

R = (Vcc - VF)/I = 687.5\ohm\ohms\Omega

Attachment 2 gives a plot of resistance (R) vs input voltage (Vcc) when a current of 20mA flows through the circuit. I hope I can proceed with this setup soon.


Attachment 1: led_circuit.pdf
Attachment 2: R_vs_V.pdf
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