ID |
Date |
Author |
Type |
Category |
Subject |
2233
|
Wed Nov 11 01:33:52 2009 |
pete | Update | CDS | RCG 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 |
pete | Update | CDS | RCG 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 |
pete | Configuration | SUS | ETMY suspension conencted to megatron ADC/DAC |
/cvs/cds/caltech/target/fb/daqd -c daqdrc
This starts the FB.
Now the dataviewer and DTT work!
Quote: |
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
/cvs/cds/caltech/target/fb/daqdrc
/cvs/cds/caltech/target/fb/master
/cvs/cds/caltech/chans/daq/C1TST.ini (via daqconfig )
- I also looked at
/cvs/cds/caltech/targetgds/param/tpchn_C1.par
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)
Quote: |
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 |
pete | Frogs | Environment | diesel 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, alberto | Update | Locking | tdsavg 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, rana | Update | Locking | crossover |
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 |
pkp | Other | OMC | OMC 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 |
pkp | Other | OMC | PZT 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 |
pkp | Update | OMC | Suspension 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
|
|
Attachment 8: Shakeleft7Nov2007_2.pdf
|
|
Attachment 9: Shakeleft7Nov2007_2.png
|
|
87
|
Fri Nov 9 00:23:12 2007 |
pkp | Update | OMC | X 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 .
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
|
|
Attachment 2: Ztransferfunc.pdf
|
|
93
|
Mon Nov 12 10:53:58 2007 |
pkp | Update | OMC | Vertical 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
|
|
102
|
Wed Nov 14 16:54:54 2007 |
pkp | Update | OMC | Much 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
|
|
Attachment 2: VerticalTranswiresclampedNov142007.pdf
|
|
105
|
Thu Nov 15 17:09:37 2007 |
pkp | Update | OMC | Vertical 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
|
|
215
|
Thu Dec 27 12:12:02 2007 |
pkp | Update | | 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 |
pkp | Update | General | Another 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 |
pkp | Update | Cameras | GigE 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 ).
Once again any suggestions welcome. |
13874
|
Mon May 21 17:36:00 2018 |
pooja | Update | Cameras | GigE 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 |
pooja | Update | Cameras | Synchronizing 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 |
pooja | Update | | |
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 |
pooja | Update | Cameras | Developing 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 |
pooja | Update | Cameras | CCD 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  
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
|
|
13951
|
Tue Jun 12 19:27:25 2018 |
pooja | Update | Cameras | CCD calibration |
Today I made the led (1050nm) circuit inside a box as given in my previous elog. Steve drilled a 1mm hole in the box as an aperture for led light.
Resistance (R) used = 665 .
We connected a power supply and IR has been detected using the card.
Later we changed the input voltage and measured the optical power using a powermeter.
Input voltage (Vcc in V) |
Optical power |
0 (dark reading) |
60 nW |
15 |
68 W |
18 |
82.5 W |
20 |
92 W |
Since the optical power values are very less, we may need to drill a larger hole.
Now the hole is approximately 7mm from led, therefore aperture angle is approximately 2*tan-1(0.5/7) = 8deg. From radiometric curve given in the datasheet of LED1050E, most of the power is within 20 deg. So a hole of size 2* tan(10) *7 = 2.5mm may be required.
I have also attached a photo of the led beam spot on the IR detection card. |
Attachment 1: IMG_20180612_163831.jpg
|
|
13972
|
Fri Jun 15 09:51:55 2018 |
pooja | Update | Cameras | Developing neural network |
Aim : To develop a neural network on simulated data.
I developed a python code that generates a 64*64 image of a white Gaussian beam spot at the centre of black background. I gave a sine wave of frequency 0.2Hz that moves the spot vertically (i.e. in pitch). Then I simulated this video at 10 frames/sec for 10 seconds. Then I saved this data into an hdf5 file, reshaped it to a 1D array and gave as input to a neural network. Out of the 100 image frames, 75 were taken as training dataset and 25 as test data. I varied several hyperparameters like learning rate of the optimizer, number of layers, nodes, activation function etc. Finally, I was successful in reducing the mean squared error with the following network model:
- Sequential model of 2 fully connected layers with 256 nodes each and a dropout of 0.1
- loss function = mean squared error, optimizer = RMSprop (learning rate = 0.00001) and activation function that adds nonlinearity = relu
- batch size = 32 and number of epochs = 1000
I have attached the plot of the output of neural network (NN) as well as sine signal applied to simulate the video and their residula error in Attachment 1. The plot of variation in mean squared error (in log scale) as number of epochs increases is given in Attachment 2.
I think this network worked easily since there is no noise in the input. Gautam suggested to try the working of this network on simulated data with a noisy background.
|
Attachment 1: nn_1.pdf
|
|
Attachment 2: nn_2.pdf
|
|
13986
|
Tue Jun 19 14:08:37 2018 |
pooja | Update | Cameras | CCD calibration using LED1050E |
Aim: To measure the optical power from led using a powermeter.
Yesterday Gautam drilled a larger hole of diameter 5mm in the box as an aperture for led (aperture angle is approximately 2*tan-1(2.5/7) = 39 deg). I repeated the measurements that I had done before (https://nodus.ligo.caltech.edu:8081/40m/13951). The measurents of optical power measured using a powermeter and the corresponding input voltages are listed below.
Input voltage (Vcc in V) |
Optical power |
0 (dark reading) |
0.8 nW |
10 |
1.05 mW |
12 |
1.15 mW |
15 |
1.47 mW |
16 |
1.56 mW |
18 |
1.81 mW |
So we are able to receive optical power close to the value (1.6mW) given in Thorlabs datasheet for LED1050E (https://www.thorlabs.com/drawings/e6da1d5608eefd5c-035CFFE5-C317-209E-7686CA23F717638B/LED1050E-SpecSheet.pdf). I hope we can proceed to BRDF measurements for CCD calibration.
Steve: did you center the LED ? |
13991
|
Wed Jun 20 20:39:36 2018 |
pooja | Update | Cameras | CCD calibration using LED1050E |
Quote: |
Aim: To measure the optical power from led using a powermeter.
Yesterday Gautam drilled a larger hole of diameter 5mm in the box as an aperture for led (aperture angle is approximately 2*tan-1(2.5/7) = 39 deg). I repeated the measurements that I had done before (https://nodus.ligo.caltech.edu:8081/40m/13951). The measurents of optical power measured using a powermeter and the corresponding input voltages are listed below.
Input voltage (Vcc in V) |
Optical power |
0 (dark reading) |
0.8 nW |
10 |
1.05 mW |
12 |
1.15 mW |
15 |
1.47 mW |
16 |
1.56 mW |
18 |
1.81 mW |
So we are able to receive optical power close to the value (1.6mW) given in Thorlabs datasheet for LED1050E (https://www.thorlabs.com/drawings/e6da1d5608eefd5c-035CFFE5-C317-209E-7686CA23F717638B/LED1050E-SpecSheet.pdf). I hope we can proceed to BRDF measurements for CCD calibration.
Steve: did you center the LED ?
|
Yes. |
14005
|
Fri Jun 22 10:42:52 2018 |
pooja | Update | | Developing neural networks |
Aim: To find a model that trains the simulated data of Gaussian beam spot moving in a vertical direction by the application of a sinusoidal signal.
All the attachments are in the zip folder.
The simulated video of beam spot motion without noise (amplitude of sinusoidal signal given = 20 pixels) is given in this link https://drive.google.com/file/d/1oCqd0Ki7wUm64QeFxmF3jRQ7gDUnuAfx/view?usp=sharing
I tried several cases:
Case 1:
I added random uniform noise (ranging from 0 to 25.5 i.e. 10% of the maximum pixel value 255) using opencv to 64*64 simulated images made in the last case( https://nodus.ligo.caltech.edu:8081/40m/13972), clipped the pixel values from 0 to 255 & trained using the same network as in the previous elog and it worked well. The variation in mean squared error with epochs is given in Attachment 1 & applied signal and output of the neural network (NN) (magnitude of the signal vs time) as well as the residual error is given in Attachment 2.
Case 2:
I simulated images 128*128 at 10 frames/sec by applying a sine wave of frequency 0.2Hz that moves the beam spot & resized it using opencv to 64*64. Then I trained 300cycles & tested with 1000 cycles with the following sequential model:
(i) Layers and number of nodes in each:
4096 (dropout = 0.1) -> 1024 (dropout = 0.1) -> 512 (dropout = 0.1) -> 256 -> 64 -> 8 -> 1
Activation : selu -> selu -> selu -> selu -> selu -> selu -> linear
(ii) loss function = mean squared error ( I used mean squared error to easily comprehend the result. Initially I had tried log(cosh) also but unfortunately I had stopped the run in between when test loss value had no improvement), optimizer = Nadam with default learning rate = 0.002
(iii) batch size = 32, no. of epochs = 400
I have attached the variation in loss function with epochs (Attachment 3). It was found that test loss value increases after ~50 epochs. To avoid overfitting, I added dropout to the layer of 256 nodes in the next model and removed the layer of 4096 nodes.
Case 3:
Same simulated data as case 2 trained with the following model,
(i) Layers and number of nodes in each:
1024 (dropout = 0.1) -> 512 (dropout = 0.1) -> 256 (dropout = 0.1) -> 64 -> 8 -> 1
Activation : selu -> selu -> selu -> selu -> selu -> linear
(ii) changed the learning rate from default value of 0.002 to 0.001. Rest of the hyperparameters same.
The variation in mean squared error in attachment 4 & NN output, applied signal & residual error (zoomed) in attachment 5. Here also test loss value increases after ~65 epochs but this fits better than the previous model as loss value is less.
Case 4:
Since in most of the examples in keras, training dataset was more than test dataset, I tried training 1000 cycles & testing with 300 cycles. The respective plots are attached as attachment 6 & 7. Here also, there is no significant improvement except that the test loss is increasing at a slower rate with epochs as compared to the last case.
Case 5:
Since most of the above cases were like overfitting (https://machinelearningmastery.com/diagnose-overfitting-underfitting-lstm-models/, https://github.com/keras-team/keras/issues/3755) except that test loss is less than train loss value in the beginning , I tried implementing case 4 with the initial model of 2 layers of 256 nodes each but with Nadam optimizer. Respective graphs in attachment 8, 9 & 10(zoomed). The loss value is slightly higher than the previous models as seen from the graph but test & train loss values converge after some epochs.
I have forgot to give ylabel in some of the graphs. It's the magnitude of the applied sine signal to move the beam spot. In most of the cases, the network almost correctly fits the data and test loss value is lower in the initial epochs. I think it's because of the dropout we added in the model & also we are training on the clean dataset.
|
Attachment 1: NN_fig.zip
|
14018
|
Tue Jun 26 10:50:14 2018 |
pooja | Update | Cameras | Beam spot tracking using OpenCV |
Aim: To track the motion of beam spot in simulated video.
I simulated a video that moves the beam spot at the centre of the image initially by applying a sinusoidal signal of frequency 0.2Hz and amplitude 1 i.e. it moves maximum by 1 pixel. It can be found in this shared google drive link (https://drive.google.com/file/d/1GYxPbsi3o9W0VXybPfPSigZtWnVn7656/view?usp=sharing). I found a program that uses Kernelized Correlation Filter (KCF) to track object motion from the video. In the program we can initially define the bounding box (rectangle) that encloses the object we want to track in the video or select the bounding box by dragging in GUI platform. Then I saved the bounding box parameters in the program (x & y coordinates of the left corner point, width & height) and plotted the variation in the y coordinates. I have yet to figure out how this tracker works since the program reads 64*64 image frames in video as 480*640 frames with 3 colour channels and frame rate also randomly changes. The plot of the output of this tracking program & the applied signal has been attached below. The output is not exactly sinusoidal because it may not be able to track very slight movement especially at the peaks where the slope = 0. |
Attachment 1: cv2_track_fig.pdf
|
|
14021
|
Tue Jun 26 17:54:59 2018 |
pooja | Update | Cameras | Developing neural networks |
Aim: To find a model that trains the simulated data of Gaussian beam spot moving in a vertical direction by the application of a sinusoidal signal. The data also includes random uniform noise ranging from 0 to 10.
All the attachments are in the zip folder.
I simulated images 128*128 at 10 frames/sec by applying a sine wave of frequency 0.2Hz that moves the beam spot, added random uniform noise ranging from 0 to 10 & resized the image frame using opencv to 64*64. 1000 cycles of this data is taken as train & 300 cycles as test data for the following cases. Optimizer = Nadam (learning rate = 0.001), loss function used = mean squared error, batch size = 32,
Case 1:
Model topology:
256 (dropout = 0.1) -> 256 (dropout = 0.1) -> 1
Activation : selu selu
Number of epochs = 240.
Variation in loss value of train & test datasets is given in Attachment 1 of the attached zip folder & the applied signal as well as the output of neural network given in Attachments 2 & 3 (zoomed version of 2).
The model fits well but there is no training since test loss is lower than train loss value. I found in several sites that dropout of some of the nodes during training but retaining them during test could be the probable reason for this (https://stackoverflow.com/questions/48393438/validation-loss-when-using-dropout , http://forums.fast.ai/t/validation-loss-lower-than-training-loss/4581 ). So I removed dropout while training next time.
Case 2:
Model topology:
256 (dropout = 0.1) -> 256 (dropout = 0.1) -> 1
Activation : selu selu linear
Number of epochs = 200.
Variation in loss value of train & test datasets is given in Attachment 4 of the attached zip folder & the applied signal as well as the output of neural network given in Attachments 5 & 6 (zoomed version of 2).
But still no improvement.
Case 3:
I changed the optimizer to Adam and tried with the same model topology & hyperparameters as case 2 with no success (Attachments 7,8 & 9).
Finally I think this is because I'm training & testing on the same data. So I'm now training with the simulated video but moving it by a maximum of 2 pixels only and testing with a video of ETMY that we had captured earlier. |
Attachment 1: NN_noise_diag.zip
|
14037
|
Wed Jul 4 20:48:32 2018 |
pooja | Update | Cameras | Medm screen for GigE |
(Gautam, Pooja)
Aim: To develop medm screen for GigE.
Gautam helped me set up the medm screen through which we can interact with the GigE camera. The steps adopted are as follows:
(i) Copied CUST_CAMERA.adl file from the location /opt/rtcds/userapps/release/cds/common/medm/ to /opt/rtcds/caltech/c1/medm/MISC/.
(ii) Made the following changes by opening CUST_CAMERA.adl in text editor.
- Changed the name of file to "/cvs/cds/rtcds/caltech/c1/medm/MISC/CUST_CAMERA.adl"
- Replaced all occurences of "/ligo/apps/linux-x86_64/camera/bin/" to "/opt/rtcds/caltech/c1/scripts/GigE/SnapPy_pypylon/" & "/ligo/cds/$(site)/$(ifo)/camera/" to "/opt/rtcds/caltech/c1/scripts/GigE/SnapPy_pypylon/"
(iii) Added this .adl file as drop-out menu 'GigE' to VIDEO/LIGHTS section of sitemap (circled in Attachment 1) i.e opened Resource Palette of VIDEO/LIGHTS, clicked on Label/Name/Args & defined macros as CAMERA=C1:CAM-ETMX,CONFIG=C1-CAM-ETMX in Arguments box of Related Display Data dialog box (circled in Attachment 2) that appears. In Related Display Data dialog box, Display label is given as GigE and Display File as ./MISC/CUST_CAMERA.adl
(iv) All the channel names can be found in Jigyasa's elog https://nodus.ligo.caltech.edu:8081/40m/13023
(v) Since the slider (circled in Attachment 3) for pixel sum was not moving, changed the high limit value to 10000000 in PV Limits dialog box. This value is set such that the slider reaches the other end on setting the exposure time to maximum.
(vii) Set the Snapshot channel C1:CAM-ETMX_SNAP to off (very important!). Otherwise we cannot interact with the camera.
(vii) GigE camera gstreamer client is run in tmux session.
Now we can change the exposure time and record a video by specifying the filename and its location using medm screen. However, while recording the video, gstream video laucher of GigE stops or is stuck. |
Attachment 1: sitemap.png
|
|
Attachment 2: GigE_macros.png
|
|
Attachment 3: CUST_CAMERA.png
|
|
14046
|
Mon Jul 9 12:36:32 2018 |
pooja | Update | General | Projector light bulb blown out |
Projector light bulb blown out today. |
14053
|
Wed Jul 11 16:50:34 2018 |
pooja | Update | Cameras | Update in developing neural networks |
Aim: To develop a neural network that resolves mirror motion from video.
I had created a python code to find the combination of hyperparameters that trains the neural network. The code (nn_hyperparam_opt.py) is present in the github repo. It's running in cluster since a few days. In the meanwhile I had just tried some combination of hyperparameters.
These give a low loss value of approximately 1e-5 but there is a large error bar for loss value since it fluctuates a lot even after 1500 epochs. This is unclear.
Input: 64*64 image frames of simulated video by applying beam motion sine wave of frequency 0.2Hz and at 10 frames per sec. This input data is given as an hdf5 file.
Train : 100 cycles, Test: 300 cycles, Optimizer = Nadam (learning rate = 0.001)
Model topology:
256 -> 128 -> 1
Activation : selu selu linear
Case 1: batch size = 48, epochs = 1000, loss function = mean squared error
Plots of output predicted by neural network (NN) & input signal has been shown in 1st graph & variation in loss value with epochs in 2nd graph.
Case 2: batch size = 32, epochs = 1500, loss function = mean squared logarithmic error
Plots of output predicted by neural network (NN) & input signal has been shown in 3rd graph & variation in loss value with epochs in 4th graph.
|
Attachment 1: graphs.pdf
|
|
14070
|
Fri Jul 13 23:23:49 2018 |
pooja | Update | Cameras | Update in developing neural networks |
Aim: To develop a neural network that resolves mirror motion from video.
I tried to reduce the overfitting problem in previous neural network by reducing the number of nodes and layers and by varying the learning rate, beta factors (exponential decay rates of moving first and second moments) of Nadam optimizer assuming error of 5% is reasonable.
Input:
32 * 32 image frames (converted to 1d array & pixel values of 0 to 255 normalized) of simulated video by applying sine signal to move beam spot in pitch with frequency 0.2Hz and at 10 frames per second.
Total: 300 cycles , Train: 60 cycles, Validation: 90 cycles, Test: 150 cycles
Model topology:
Input --> Hidden layer --> Output layer
4 nodes 1 node
Activation function: selu linear
Batch size = 32, Number of epochs = 128, loss function = mean squared error
Optimizer: Nadam
Case 1:
Learning rate = 0.00001, beta_1 = 0.8 (default value in Keras = 0.9), beta_2 = 0.85 (default value in Keras = 0.999)
Plot of predicted output by neural network, applied input signal & residual error given in 1st attachment.
Case 2:
Changed number of nodes in hidden layer from 4 to 8. All other parameters same.
These plots show that when residual error increases basically the output of neural network has a smaller amplitude compared to the applied signal. This kind of training error is unclear to me.
When beta parameters of optimizer is changed farther from 1, error increases. |
Attachment 1: nn_simulation_2_nodes4_lr0p00001_beta1_0p8_beta2_0p85.pdf
|
|
Attachment 2: nn_simulation_2_nodes8_lr0p00001_beta1_0p8_beta2_0p85.pdf
|
|
14089
|
Thu Jul 19 18:09:17 2018 |
pooja | Update | Cameras | Update in developing neural networks |
Aim: To develop a neural network that resolves mirror motion from video.
Case 1:
Input : Simulated video of beam spot motion in pitch by applying 4 sine waves of frquencies 0.2, 0.4, 0.1, 0.3 Hz and amplitude ratios to frame size to be 0.1, 0.04, 0.05, 0.08
The data has been split into train, validation and test datasets and I tried training on neural network with the same model topology & parameters as in my previous elog (https://nodus.ligo.caltech.edu:8081/40m/14070)
The output of NN and residual error have been shown in Attachment 1. This NN model gives a large error for this. So I think we have to increase the number of nodes and learning rate so that we get a lower error value with a single sine wave simulated video ( but not overfitting) and then try training on linear combination of sine waves.
Case 2 :
Normalized the target sine signal of NN so that it ranges from -1 to 1 and then trained on the same neural network as in my previous elog with simulated video created using single sine wave. This gave comparatively lower error (shown in Attachment 2). But if we train using this network, we can get only the frequency of test mass motion but we can't resolve the amount by which test mass moves. So I'm unclear about whether we can use this. |
Attachment 1: nn_simulation_mlt_sine_nodes4_lr0p00001_beta1_0p8_beta2_0p85_marked.pdf
|
|
Attachment 2: nn_simulation_2_nodes4_target-1to1_marked.pdf
|
|
14097
|
Sun Jul 22 14:01:07 2018 |
pooja | Update | Cameras | Developing neural networks on simulated video |
Aim: To develop a neural network that resolves mirror motion from video.
Since error was high for the same input as in my previous elog http://nodus.ligo.caltech.edu:8080/40m/14089
I modified the network topology by tuning the number of nodes, layers and learning rate so that the model fitted the sum of 4 sine waves efficiently, saved weights of the final epoch and then in a different program, loaded saved weights & tested on simulated video that's produced by moving beam spot from the centre of image by sum of 4 sine waves whose frequencies and amplitudes change with time.
Input : Simulated video of beam spot motion in pitch by applying 4 sine waves of frquencies 0.2, 0.4, 0.1, 0.3 Hz and amplitude ratios to frame size to be 0.1, 0.04, 0.05, 0.08. This is divided into train (0.4), validation (0.1) and test (0.5).
Model topology:
Input --> Hidden layer --> Output layer
8 nodes 1 node
Activation function: selu linear
Batch size = 32, Number of epochs = 128, loss function = mean squared error
Optimizer: Nadam ( learning rate = 0.00001, beta_1 = 0.8, beta_2 = 0.85)
Normalized the target sine signal of NN by dividing by its maximum value.
Plot of predicted output by neural network, applied input signal & residual error given in 1st attachment. These weights of the model in the final epoch have been saved to h5 file and then loaded & tested with simulated data of 4 sine waves with amplitudes and frequencies changing with time from their initial values by random uniform noise ranging from 0 to 0.05. Plot of predicted output by neural network, target signal of sine waves & residual error given in 2nd attachment. The actual signal can be got from predicted output of NN by multiplication with normalization constant used before. However, even though network fits training & validation sets efficiently, it gives a comparatively large error on test data of varying amplitude & frequency.
Gautam suggested to try training on this noisy data of varying amplitudes and frequencies. The results using the same model of NN is given in Attachment 3. It was found that tuning the number of nodes, layers or learning rate didn't improve fitting much in this case.
|
Attachment 1: nn_simulation_2_normalized_mult_sin_nodes8_128epochs_lr0p00001_beta1_0p8_beta2_0p85_0p4train_0p1valid_marked.pdf
|
|
Attachment 2: nn_simulation_normalizedtarget_128epochs_mult_sin_load_wt_varyingtest_nodes8_lr0p00001_beta1_0p8_beta2_0p85_0p4train_0p1valid_marked.pdf
|
|
Attachment 3: nn_simulation_2_normalized_varying_mult_sin_nodes8_128epochs_lr0p00001_beta1_0p8_beta2_0p85_0p4train_0p1valid_marked.pdf
|
|
14114
|
Sun Jul 29 23:15:34 2018 |
pooja | Update | Cameras | Developing CNN |
Aim: To develop a convolutional neural network that resolves mirror motion from video.
Input : Previous simulated video of beam spot motion in pitch by applying 4 sine waves of frquencies 0.2, 0.4, 0.1, 0.3 Hz and amplitude ratios to frame size to be 0.1, 0.04, 0.05, 0.08 where random uniform noise ranging 0.05 has been added to amplitudes and frequencies. This is divided into train (0.4), validation (0.1) and test (0.5).
Model topology:
- Number of filters = 2
- Kernel size = 2
- Size of pooling windows = 2
- -----> Dense layer of 4 nodes ----> Output layer of 1 node
Activation: selu linear
Batch size = 32, Number of epochs = 128, loss function = mean squared error
Optimizer: Nadam ( learning rate = 0.00001, beta_1 = 0.8, beta_2 = 0.85)
Plots of CNN output & applied signal given in Attachment 1. The variation in loss value with epochs given in Attachment 2.
This needs to be further analysed with increasing random uniform noise over the pixels and by training CNN on simulated data of varying ampltides and frequencies for sine waves. |
Attachment 1: conv_nn_varying_freq_amp_1.pdf
|
|
Attachment 2: conv_nn_varying_freq_amp_2.pdf
|
|
1
|
Wed Oct 17 18:46:33 2007 |
rana | Configuration | General | eLog Change |
This is the first entry in the new 40m eLog.
Its GWs or bust now! 
[Hnull][/Hnull] |
2
|
Thu Oct 18 14:52:35 2007 |
rana | Routine | ASC | test |
test
X-(:P;(:)) |
9
|
Tue Oct 23 09:01:00 2007 |
rana | Other | OMC | PZT calibration/ transfer function. |
Are you sure that the error signal sweep is not saturated on the top ends? This is usually the downfall
of this calibration method. |
13
|
Thu Oct 25 00:01:21 2007 |
rana | Software Installation | CDS | GEO DV => LIGO DV |
Martin Hewitson of GEO600 fame has modified the cool GEO DV
to work with the LIGO NDS system with some NDS advice from Rolf (who's over in Germany this week).
I've moved it onto the 40m CDS system and installed it on the AdhikariLab computer named 'django'. It worked immediately.
I modified the main .m file to include the 40m's NDS server. When you run it you have to include the path to the NDS
client written by Ben Johnson.
The attached is a screenshot of it working on a Mac; it looks as cool on Linux.
Its installed in /cvs/cds/caltech/apps/ligoDV/. In matlab you navigate to that directory and then
type addpath('/cvs/cds/caltech/apps/linux/UNIX_NDS_Client_beta2/') to add the NDS client.
On the Solaris machines, type type addpath('/cvs/cds/caltech/apps/solaris9/UNIX_NDS_Client_beta2/') instead.
Then type ligoDV to start it up. Then click away and have fun.
In the example I've selected C1:PEM-BS_ACC_EAST_Z and plotted its specgram.
 |
Attachment 1: Picture_1.png
|
|
22
|
Sun Oct 28 03:03:42 2007 |
rana | Configuration | IOO | Three Way Excitement |
We've been trying to measure the MC mirror internal mode frequencies so that we can measure
their absorption before and after drag wiping.
It looked nearly impossible to see these modes as driven by their thermal excitation level;
we're looking at the "MC_F" or 'servo' output directly on the MC servo board.
Today, I set up a band limited noise drive into the 'Fast POS' inputs of the 3 MC coil
driver boards (turns out you can do this with either the old HP or the SR785).
Frequencies:
MC1 28.21625 kHz
MC2 28.036 kHz
MC3 28.21637 kHz
I don't really have this kind of absolute accuracy. These are just numbers read off of the SR785.
The other side of the setup is that the same "MC_F" signal is going into the SR830 Lock-In which
is set to 'lock-in' at 27.8 kHz. The resulting demodulated 'R" signal (magnitude) is going into
our MC_AO channel (110B ADC).
As you can see from the above table, MC1 and MC3 are astonishingly and annoyingly very close in
frequency. I identified mirrors with peaks by driving one at a time and measuring on the spectrum
analyzer. I repeated it several times to make sure I wasn't fooling myself; it seems like they
are really very close but distinct peaks. I really wish we had chipped one of these mirrors
before installing them.
Because of the closeness of these drumhead modes, we will have to measure the absorption by making long
measurements of this channel. |
29
|
Tue Oct 30 00:47:29 2007 |
rana | Other | IOO | MC Ringdowns |
I did a bunch of MC ringdown measurements using the PD that Rob set up. The idea is to put a fast PD (PDA255)
looking at the transmission through MC2 after focusing by a fast lens. The input to the MC is turned off fast
by flipping the sign of the FSS (Andri Gretarsson's technique).
With the laptop sitting on the MC can, its easy to repeat many ringdowns fast:
- Turn off the MC autolocker. Relock the MC with only the acquisition settings; no boosts
and no RGs. This makes it re-acquire fast. Turn the MC-WFS gain down to 0.001 so that
it keeps it slowly aligned but does not drift off when you lose lock.
- Use low-ish gain on the FSS. 10 dB lower than nominal is fine.
- Setup the o'scope (100 MHz BW or greater) to do single shot trigger on the MC2 trans.
- Flip FSS sign.
- Quickly flip sign back and waggle common gain to get FSS to stop oscillating. MC
should relock in seconds.
Clearly one can scriptify this all just by hooking up the scope to the ethernet port.
Attached are a bunch of PNG of the ringdowns as well as a tarball with the actual data. A sugar
napoleon to whomever can explain the 7 us period of the wiggle before the vent! |
Attachment 1: tek00000.png
|
|
Attachment 2: tek00001.png
|
|
Attachment 3: tek00004.png
|
|
Attachment 4: MC2ringdown.tar.gz
|
34
|
Wed Oct 31 08:33:54 2007 |
rana | Problem Fixed | SUS | Vent measurements |
There was a power outage during the day yesterday; whoever was around should post something here about the
exact times. Andrey and David and Tobin got the computers back up - there were some hiccups which you can
read about in David's forthcoming elog entry.
We restarted a few of the locking scripts on op340m: FSSSlowServo, MCautolocker. Along with the updates
to the cold restart procedures we have to put an entry in there for op340m and a list of what scripts
to restart.
David tuned up the FSS Slow PID parameters a little; he and Andrey will log some entry about the proper
PID recipe very soon. We tested the new settings and the step response looks good.
We got the MC locking with no fuss. The 5.6 EQ in San Francisco tripped all of the watchdogs and I upped
the trip levels to keep them OK. We should hound Rob relentlessly to put the watchdog rampdown.pl into
the crontab for op340m. |
35
|
Wed Oct 31 08:34:35 2007 |
rana | Other | IOO | loss measurements |
In the end, we were unable to get a good scatter measurement just because we ran out of steam. The idea was to get a frame
grab image of MC2 but that involves getting an unsaturated image.
In the end we settle for the ringdowns, Rob's (so far unlogged) cavity pole measurement, and the MC transmission numbers. They
all point to ~100-150 ppm scatter loss per mirror. We'll see what happens after wiping. |
36
|
Wed Oct 31 08:38:35 2007 |
rana | Problem Fixed | IOO | MC autolocker |
The MC was having some trouble staying locked yesterday. I tracked this down to some steps in the last
half of the mcup script; not sure exactly which ones.
It was doing something that made the FAST of the PSL go to a rail too fast for the SLOW to fix.
So, I broke the script in half so that the autolocker only runs the first part. We'll need to
fix this before any CM locking can occur.
We also need someone to take a look at the FSS Autolocker; its ill. |
61
|
Sun Nov 4 23:55:24 2007 |
rana | Update | IOO | Friday's In-Vac work |
On Friday morning when closing up we noticed that we could not get the MC to flash any modes.
We tracked this down to a misalignment of MC3. Rob went in and noticed that the stops were
still touching. Even after backing those off the beam from MC3 was hitting the east edge of
the MC tube within 12" of MC3.
This implied a misalignment of MC of ~5 mrad which is quite
large. At the end our best guess is that either I didn't put the indicator blocks in the
right place or that the MC3 tower was not slid all the way back into place. Since there
is such a strong stickiness between the table and the base of the tower its easy to
imagine the tower was misplaced.
So we looked at the beam on MC2 and twisted the MC3 tower. This got the beam back onto the
MC2 cage and required ~1/3 if the MC3 bias range to get the beam onto the center. We used
a good technique of finding that accurately: put an IR card in front of MC2 and then look
in from the south viewport of the MC2 chamber to eyeball the spot relative to the OSEMs.
Hitting MC2 in the middle instantly got us multiple round trips of the beam so we decided
to close up. First thing Monday we will put on the MC1/MC3 access connector and then
pump down.
Its possible that the MC length has changed by ~1-2 mm. So we should remeasure the length
and see if we need to reset frequencies and rephase stuff. |
62
|
Mon Nov 5 07:29:35 2007 |
rana | Update | IOO | Friday's In-Vac work |
Liyuan recently did some of his pencil beam scatterometer measurements measuring not the
BRDF but instead the total integrated power radiated from each surface point
of some of the spare small optics (e.g. MMT, MC1, etc.).
The results are here on the iLIGO Wiki.
So some of our loss might just be part of the coating. |
91
|
Sun Nov 11 21:05:55 2007 |
rana | HowTo | SUS | MC Touching or not |
I wrote a script: SUS/freeswing-mc.csh, which gives the MC mirrors the appropriate kicks
needed to make a measurement of the free swinging peaks in the way that Sonia did.
#!/bin/csh
set ifo = C1
set sus = ${ifo}:SUS-
foreach opt (MC1 MC2 MC3)
set c = `ezcaread -n ${sus}${opt}_PD_MAX_VAR`
ezcastep ${sus}${opt}_PD_MAX_VAR +300
ezcaswitch ${sus}${opt}_ULCOIL OFFSET ON
ezcawrite ${sus}${opt}_ULCOIL_OFFSET 30000
sleep 1
ezcawrite ${sus}${opt}_ULCOIL_OFFSET 0
sleep 1
ezcawrite ${sus}${opt}_ULCOIL_OFFSET 30000
sleep 1
ezcawrite ${sus}${opt}_LATCH_OFF 0
ezcawrite ${sus}${opt}_ULCOIL_OFFSET 0
ezcaswitch ${sus}${opt}_ULCOIL OFFSET OFF
ezcawrite ${sus}${opt}_PD_MAX_VAR $c
end
echo
date
echo
It basically ups the watchdog threshold, wacks it around at the pendulum frequency, and then disables the
optic so that there are no electronic forces applied to it besides the bias. The date command at the end
is so that you know when to start your DTT or mDV or lalapps code or whatever. |
92
|
Sun Nov 11 21:21:04 2007 |
rana | HowTo | Computers | New DV |
To use the new ligoDV (previously GEO DV) to look at 40m data, open up a matlab, set up for mDV as usual,
and then from the /cvs/cds/caltech/apps/ligoDV/ directory, type 'ligoDV'.
Then select which NDS server you want to look at and then start clicking to get some plots. |
Attachment 1: Screenshot-1.png
|
|
128
|
Wed Nov 28 04:21:46 2007 |
rana | Update | PSL | FSS |
Quote: | Rana, Tobin
We looked at the RF PD signal to the FSS (siphoning off a signal via a minicircuits directional coupler) and also took an open loop transfer function of the FSS. In the transfer function we saw the step at 100 kHz (mentioned by Rob) as well as some peculiar behavior at high frequency. The high frequency behavior (with a coupling of ~ -20 dB) turns out to be bogus, as it is still present even with the beam blocked. Rearranging the cabling had no effect; the cause is apparently inside the FSS. The step at 100 kHz turns out to be a saturation effect, as it moved as we lowered the signal amplitude, disappearing as we approached -60 dBm. (Above the step, the measurement data is valid; below, bogus.)
Transfer functions will be attached to this entry.
Some things to check tomorrow: the RF signal to the PC, RF AM generation by the PC, LO drive level into the FSS, RF reflection from the PC, efficiency of FSS optical path, quality of RF cabling. |
I would also add to Tobin's entry that we believe what Rob was seeing was saturation.
With the bi-directional coupler in there, the RF signal into the FSS board clearly went UP if moved the offset slider away from zero.
With a scope looking at the IN2 testpoint, we can see that there's less than 2 mV offset at zero slider offset.
One tangential thing we noticed with the coupler is that, in lock, the amount of reflected RF is around the same as that going in to the mixer.
I have always wanted to look at this but have only had uni-directional couplers in the past. I think that the double balanced mixer is inherently
not a 50 Ohm device during the times where the diodes are being switched. IF that's the case we might do better in the future by having an RF
buffer on board just before the mixer to isolate the PD head from these reflections. |
132
|
Wed Nov 28 16:46:28 2007 |
rana | Configuration | Computers | scientific linux 5.0 |
I tried installing Scientific Linux on Tiramisu. The installation process was so bad (really)
that I quit after 15 minutes. Its back to booting Ubuntu as if nothing had ever happened. Let
us never speak of Scientific Linux again. |