40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  40m Log, Page 321 of 329  Not logged in ELOG logo
ID Date Authorup Type Category Subject
  117   Tue Nov 20 11:10:07 2007 tobinUpdateComputersepics access from matlab
I installed "labca", which allows direct access to EPICS channels from within Matlab. It comes with both Linux and Solaris binaries (and source) but I've only tried it on linux.

To set it up, run these shell commands:
pushd /cvs/cds/caltech/users/tf/build/labca_2_1/bin/linux-x86
setenv PATH ${PATH}:`pwd`
cd /cvs/cds/caltech/users/tf/build/labca_2_1/lib/linux-x86
setenv LD_LIBRARY_PATH ${LD_LIBRARY_PATH}:`pwd`
popd
Then start matlab, and within matlab type:
addpath /cvs/cds/caltech/users/tf/build/labca_2_1/bin/linux-x86/labca
help labca
foo = lcaGet('C1:PSL-FSS_RCTRANSPD')
It seems like reasonably well-written software, and is being actively maintained right now. If we like it, I can build a more recent version, install it in a more permanent location, etc.
  118   Tue Nov 20 13:06:57 2007 tobinConfigurationComputerslinux1 has new disk
Alex put the new hard disk into linux1 along with a fresh install of linux (CentOS). The old disk was too damaged to copy.

Alex speculates that the old disk failed due to overheating and that linux1 could use an extra fan to prevent this in the future.
  127   Tue Nov 27 20:47:00 2007 tobinUpdatePSLFSS
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.
Attachment 1: fss-tf0001.pdf
fss-tf0001.pdf fss-tf0001.pdf
  136   Wed Nov 28 19:44:18 2007 tobinUpdatePSLHEPA
I found the HEPA turned off completely. I turned it on.
  137   Wed Nov 28 21:51:52 2007 tobinConfigurationPSLISS
I replaced the front-end differential receivers for the ISS's "inner-loop" sensor and monitor diode inputs with lower-noise THS4131's (formerly THS4151's). I verified operation by taking the transfer function from the "PD+" and "PD-" inputs (separately) to the testpoint following the differential receiver; the surgery appears successful.

I measured the dark spectra at the ISS's DC PD BNC ports and found a noise floor of ~ 16 nV/rtHz, compared with a floor of ~ 22 nV/rtHz last week. This seems to add up, assuming the DC PD port has 0dB gain: the 4131 has a rated noise of 1.3 nV/rtHz and the 4151 a noise floor of 7.6 nV/rtHz, a difference of 6 nV/rtHz. The other change made in that time was to add a larger power supply bypass capacitor in the PD.

There are two of the old 4151 chips still on the ISS board on the two "outer-loop" channels that we don't use. If I dig up any more 5131's I will replace these too for completeness.

There is currently no light on the ISS diodes; I'm not sure where it's intended to come from.
  140   Thu Nov 29 14:29:22 2007 tobinConfigurationComputerslinux1 httpd/conlogger fixed
I think I fixed the conlogger web interface on linux1.

Steps necessary to do this:
0. Run "/etc/init.d/httpd start" to start up httpd right now
1. Run "/usr/sbin/ntsysv" and configure httpd to be started automatically in the future
2. Copy /cvs/cds/caltech/conlogger/bin/conlog_web.pl to /var/www/cgi-bin and chown to controls
8. Hack the conlog_web.pl to (0) use /usr/bin/perl (1) not use Apache::Util, and (2) function with the newer version of CGI.pm
9. Enjoy!

The following steps are optional, and may be inserted between steps 2 and 8:
3. Try to install Apache::Util (via "perl -MCPAN -e shell" followed by "Install Apache::Util")
4. Notice that the installation dies because there is no C compiler installed
5. Bang head in disgust and abomination over a Linux distribution shipping without a C compiler installed by default
6. "yum install gcc"
7. Annoyed by further dependencies, go to step 8
  158   Mon Dec 3 16:24:47 2007 tobinHowToComputersGNU screen
GNU screen is a utility that can be quite handy for managing long-running psuedo-interactive terminal programs on remote machines. In particular, I think it might be useful in developing and testing "Matlab DMT" tools on Mafalda.
  159   Mon Dec 3 17:55:39 2007 tobinHowToComputer Scripts / Programslinemon
Matlab's Signal Processing toolbox has a set of algorithms for identifying sinusoids in data. Some of them (e.g., rootmusic) take the number of sinusoids to find as an argument and return the "most probable N frequencies." These could be useful in line monitoring.
  162   Mon Dec 3 22:20:09 2007 tobinConfigurationPSLISS
I replaced the painfully short 1' cables on the ISS photodiodes with luxurious five foot cables, made by chopping a ten foot Amphenol cable (P/N:CS-DSPMDB09MM-010) in half and using each half for one of the diodes. All of the ISS GND connections are wired to the PD GND, as is the PD- differential signal. The diodes are installed on the PSL table, but I have not tested them beyond looking at the DC values as I blocked/unblocked the beam.
  163   Tue Dec 4 23:16:35 2007 tobinUpdatePSLISS
I was confused to find that I could increase the ISS gain slider all the way from 15dB to 30dB without seeing much of any increase in gain in the measured open-loop transfer function. While making these swept-sine measurements, the saturation indicator almost never tripped, indicating it was seemingly happy. But then I noticed an odd thing: if I disable the test ("analog excitation") input, the saturation indicator trips immediately. I hooked up a scope to the current shunt test point (TP12). With the test input enabled, the loop closed, and the analog excitation port connected to the SR785, I see a a 5 Vpkpk, 2.55 MHz triangle wave there. It is there even if I set the SR785 excitation amplitude to zero, but it disappears if I disconnect the cable from the SR785.

I found oscillations at TP20, TP30, TP36, TP41, and TP42. Many of these are in the (unused) "outer loop" circuitry and currently lack compensation capacitors.
  166   Wed Dec 5 16:57:36 2007 tobinHowToComputer Scripts / ProgramsSR785 data converter on linux
I was pleased to find that the SR785 Data Viewer (including the command line conversion utility) installs and works in linux using WINE (on my laptop at least). There are some quirks, of course, but I was able to extract my data.
  167   Wed Dec 5 17:49:57 2007 tobinUpdatePSLISS
Attached is a plot of the ISS RIN with a variety of gain settings.

Unfortunately the dark noise is huge now--a result of the new cables & wiring?
Attachment 1: rin.pdf
rin.pdf
  169   Wed Dec 5 18:22:03 2007 tobinUpdatePSLISS dark noise
Attached is a plot of the dark noise spectrum of the ISS photodiodes (1) before fooling with them, (2) after replacing the 4151's with 4131's (improvement!), and (3) after replacing the cables and changing the wiring (disaster!).
Attachment 1: sense_noise.pdf
sense_noise.pdf
  171   Wed Dec 5 20:32:51 2007 tobinUpdatePSLISS dark noise
The ISS dark noise is not coming from the PD heads; the spectrum is essentially unchanged when the PD is unplugged from the ISS. Did the input opamps both get semi-fried in the same way? (They worked so well when they were first installed.) What else changed? I'm baffled. Frown
  177   Thu Dec 6 19:30:43 2007 tobinUpdatePSLISS dark noise - 60 Hz!
A higher resolution spectrum [attached] shows that nearly all of the excess dark noise on the ISS is in 60 Hz harmonics (with some 256 Hz harmonics too--are these from the DAQ?).

With the loop closed and the slider at 5dB, the laser light coming out has a noise floor of 10^-7 RIN or better from 40 Hz to 8 kHz.

Now to figure out why all this 60 Hz is getting in... (I tried turning off all the lights and the HEPA, and moving the SR785 further away, none of which did anything.)
Attachment 1: iss.pdf
iss.pdf
  181   Fri Dec 7 18:28:30 2007 tobinUpdateComputer Scripts / Programscompiled matlab hoses itself
Andrey pointed out to me that some matlab functions in the Signal Processing Toolbox were dying with errors. Looking into the .m file (identified using the "which" command), I was surprised to see binary garbage rather than glistening, clear Matlab prose. Then I noticed the directory in which it was finding the .m file:
>> which decimate
/cvs/cds/caltech/apps/mDV/extra/linetrack_c_mcr/toolbox/signal/signal/decimate.m
See that "linetrack_c_mcr" directory? This is what is generated when a "compiled" (grumble) Matlab program is run--it decompresses itself into a subdirectory containing weird semi-compiled binary .m files. Unfortunately this is somehow getting incorporated into the matlab path. (I assume there is something in mDV that says "put all subdirectories into the path.")

I hate the Matlab compiler.
  182   Fri Dec 7 18:31:30 2007 tobinUpdateComputer Scripts / Programscompiled matlab hoses itself
Addendnum. The reason the linemon_mcr command was in the path was because of the user issuing the command "addpath(genpath(pwd))" where genpath(D) "returns a path string starting in D, plus, recursively, all the subdirectories of D."

The Matlab compiler is still bad, however.
  183   Fri Dec 7 19:14:30 2007 tobinUpdatePSLISS dark noise - ground loop enlightenment
My alleged 60 Hz harmonics were all from a ground loop created by connecting the SR785 ground to the ISS circuit ground; they disappeared when I set the SR785 input to "floating ground." doh!

I modified the ISS PD's to have a 100 ohm resistor in series with the output (in place of 20 ohms). The diodes are again in place on the table, ready for action.
  185   Mon Dec 10 18:42:20 2007 tobinUpdatePSLISS RIN script
I wrote a script to measure the ISS RIN. The script uses the "labca" interface (described in an earlier entry) to read and twiddle EPICS settings and mDV to get DAQ data. The script measures open loop RIN, closed loop RIN at each of several gain slider settings, and dark noise. The dark noise is obtained by misaligning (unlocking) the PMC. The script also compares the whitened and unwhitened spectra for an open loop measurement and performs a fit of a simple pole to find the dewhitening filter.

This is all very exciting, but I don't quite believe the results, since the closed loop RIN seems to bottom out at 2e-7/rtHz regardless of the gain slider setting.

Sample output attached. The script may be found at scripts/PSL/ISS/rin.m.
Attachment 1: rin-20071210-1831.pdf
rin-20071210-1831.pdf
  186   Mon Dec 10 19:08:03 2007 tobinConfigurationPSLMZ
The MZ seems finicky today--it keeps unlocking and relocking.

I've temporarily blocked one of the MZ arms while I work on the ISS.
  187   Mon Dec 10 20:35:59 2007 tobinConfigurationComputer Scripts / Programsautolocking scripts
I added this tidbit of csh code to the MZ autolocker to prevent multiple copies from running (on one computer):
if (`pgrep lockMZ | wc -l` > 1) then
   echo lockMZ is already running! 
   exit
endif
Similarly, here's some bash code that does something similar; I'll add it to the other autolocker scripts:
if                                                                                                                       
  pgrep `basename $0` | grep -v $$ > /dev/null                                                                           
then                                                                                                                     
  echo Another copy of this program is already running.  Exiting!                                                        
  exit 1                                                                                                                 
fi
This code searches for all processes with the same name as this script ($0) and then use grep to exclude (-v) the current process ID ($$).
  189   Wed Dec 12 22:24:48 2007 tobinFrogsPEMweather station
I poked at the weather station briefly this evening.

* There's almost nothing in the elog about it.
* It exists. It is located on the North wall, just north of the beam splitter.
* It seems to be displaying reasonable data for the indoors, but nothing for the outdoor sensors.
* c1pem didn't seem to be starting up (couldn't telnet into it, etc). I altered its startup file and reset it several times, and eventually it came to life.
* the weather station has a serial cable that goes all the way to c1pem. I plugged it in.
* however, the Weather.st program complains "NO COMM"--it gets no data from the weather station
* The next thing to do is to plug in a laptop to that serial cable and see if the weather station can be convinced to talk.
  196   Tue Dec 18 16:50:35 2007 tobinUpdateSAFETYuvex laser safety glasses defective
A few days ago we noticed what appeared to be a blotched, speckled fracturing of the coating of the "UVEX" laser safety glasses. These are the glasses with "transparent" (reflective to 1064nm) lenses and white frames that we keep in a box on top of a filing cabinet in the control room. Today Steve measured the transmission of these glasses and found 80% transmission of 1064nm in several cases.

Do not use the white, transparent "uvex" laser safety glasses until further notice. Steve has hidden them away so that you won't be tempted.

Below is attached a photo of a bad lens.
Attachment 1: bad-glasses.jpg
bad-glasses.jpg
Attachment 2: bad-glasses-zoom.jpg
bad-glasses-zoom.jpg
  197   Tue Dec 18 21:31:31 2007 tobinUpdatePSLISS RIN
My measurements of the ISS RIN via the SR785 and via the DAQ disagree considerably. The spectral shapes are very similar, however, so I expect that a constant factor is creeping in somewhere. Measurements taken at the PD DC monitor points using the SR785 attached. There is a lot of excess noise in the 300 Hz - 1 kHz region.
Attachment 1: iss-rin.pdf
iss-rin.pdf
  210   Fri Dec 21 20:32:25 2007 tobinUpdatePhotosGigE camera
I couldn't resist any longer: I plugged in the Prosilica GC 750 GigE camera and took it for a spin. This is the little CMOS camera which sends out video over gigabit ethernet.

There were no difficulties at all in getting it running. I just plugged in the power, plugged in ethernet, and put on a lens from Steve's collection. I downloaded the "Sample Viewer" from the Prosilica website and it worked immediately.

It turns out that "Kirk's" computer has not only a gigabit ethernet card, but a little gigabit ethernet switch. I plugged the camera into this switch. The frame rate is amazing. With the camera under fluorescent lights I thought I saw some wacky automatic gain control, but I think this ~10Hz flicker is aliasing of the 60 Hz room lighting.

I put the camera on the PSL table briefly and tried viewing the image from a laptop over the (54mbs) wireless network. This didn't work so well: you could get a couple frames out of the camera, but then the client software would complain that it had lost communications. It appeared that scattered 1064nm light did show up brightly on the camera image. There is a green ethernet cable currently stashed on the roof of the PSL that appears unused. We can try mounting the gigE CMOS cable in place of one of the CCD video cameras.

I did not try the Linux software.

The camera is currently set up at Kirk's desk, using the cool little tripod Rana got from CyberGuys.

This camera looks very promising! Also, in the test image attached below, a very unusual condition has been documented.
Attachment 1: robs_desk.png
robs_desk.png
  211   Sat Dec 22 00:52:57 2007 tobinConfigurationPSLISS surgery
In an attempt to quell oscillations in the (unused) outer loop portion of the ISS, I shorted the "PD+" and "PD-" signals from the (nonexistent) outer-loop diodes, and soldered in 47pf compensation capacitors in C92 and C220. This seems to have eliminated oscillations seen at TP41 and TP42. There's still something amiss at TP30 and maybe TP20. Otherwise, the ISS seems happy. I can turn the gain slider to +15dB without saturation (with the HEPA off), though there seems to be less light on the diode (~3.9V) than a week or two ago.
  212   Sat Dec 22 15:32:11 2007 tobinAoGEnvironmentants
Ants are everywhere: on the PSL table, on the circuit board I'm soldering...

I believe I have discovered their energy source.
Attachment 1: DSC_0361.JPG
DSC_0361.JPG
  219   Wed Jan 2 11:38:56 2008 tobinSummaryWIKI-40M Updatewiki spam
Our wiki keeps getting spammed. It turns out that you can upload attachments without a password, which is a bug. I'll ask David Barker whether there's a fix for this.
  231   Thu Jan 10 00:12:01 2008 tobinSummaryLockingDR
[John, Tobin, Rana]

1. We found SUS_BS_SENSOR_UL to have a ratty signal and low DC value. Twiddling the cables at the BS satellite amplifier and vacuum feedthrough brought the signal back (to 0.667V), but it is still spiky, spiking up to a couple times per second. Rana suggested that these spikes might be scattered YAG laser light (as hypothesized in August). The spikes go away when we misalign the PRM or either ITM, and when we unlock the mode cleaner, lending credance to this theory. SUS_BS_SENSOR_UR also spikes, but much less frequently. We turned off C1:SUS-BS_ULSEN_SW2 and continued.

2. After dither alignment the oplev beams were centred and we were able to lock DRM plus either arm reliably (however locking in this state broke ./drstep_bang at the first ``Going DD''). We ran scripts/DRFPMI/bang/nospring/drdown_bang and were subsequently able to lock DRFPMI (i.e., full IFO) a couple times.

3. To do: Debug ./drstep_bang with just the DRM (no arms).
  238   Mon Jan 14 23:11:26 2008 tobinConfigurationGeneralfiber
John and I removed the fiber that ran from the SP table to the cleanroom. We plan to build a MZ interferometer with this fiber inserted into one of the arms, for the purpose of measuring its phase noise.
  239   Tue Jan 15 13:15:27 2008 tobinUpdateEnvironmentlots of noise
They're throwing concrete around at the construction site.
  243   Wed Jan 16 19:57:49 2008 tobinConfigurationPhotosISCT_EX
Here's a photo of the ISCT_EX table, for the purpose of planning our auxiliary laser arm locking scheme. Note the (undumped!) beam from the beamsplitter before QPDX (the leftmost gold-colored box); perhaps we could inject there.
Attachment 1: trx-annotated-small.jpg
trx-annotated-small.jpg
  247   Thu Jan 17 20:50:55 2008 tobinUpdateGeneralfiber coupling
Sam, John, and I matched the beam from an NPRO into a fiber on the SP table today. In doing so we used our GigE camera for a physics application for perhaps the first time, viewing the transmitted mode from the fiber during initial alignment. (I used my laptop running Windows and a 100 megabit switch.)
  250   Fri Jan 18 20:53:56 2008 tobinConfigurationGeneralETMY oplev
I monkeyed around with the ETMY oplev, adding a folding mirror and moving the HeNe so that John, Sam, and I have more room for our auxiliary laser setup. (The ISCT-EY has more room than ISCT-EX; the latter has an extra photodiode for IP ANG.) I believe I successfully recommissioned the oplev, though it might not be up to the SV standard. I verified that wiggling the ETMY alignment sliders showed corresponding wiggles in the oplev signals. However, it seems poorly diagonalized.

Our current plan is to have an NPRO, EOM, and fiber coupler on the SP table. This fiber will take light to ISCT-EY where we'll have a mode-matching telescope and inject light to the Y arm via a polarized beamsplitter. This auxiliary beam will have polarization orthogonal to the beam from the PSL.
  253   Tue Jan 22 13:11:03 2008 tobinUpdateASCETMY oplev recentered
The light wasn't even on the diode.
  277   Sun Jan 27 13:13:21 2008 tobinMetaphysicsGeneraldeparture
It's been grand. Thanks for having me!

GWAVES IN '08!

Sugar napoleons may be forwarded to T. F., c/o LLO, P.O. Box 940, Livingston, LA 70754-0940.
  498   Sun May 25 21:14:14 2008 tobinConfigurationComputersEPICS proxy server
I set up an EPICS gateway server on Nodus so that we can look at 40m MEDM screens from off-site.
The gateway is set up to allow read access to all channels and write access to none of them.

The executable is /cvs/cds/epics/extensions/gateway; it was already installed. A script to start
up the gateway is in target/epics-gateway. For the time being, I haven't set it up to start itself
on boot or anything like that.

To make it work, you have to set the environment variable EPICS_CA_ADDR_LIST to the IP address of
Nodus. For instance, something like this should work:

setenv EPICS_CA_ADDR_LIST 131.215.115.52

On Windows you can set up environment variables in the "System" Control Panel. On one of the tabs
there's a button that lets you set up environment variables that will be visible to all programs.

On Andrey's machine I installed the Windows EPICS extensions, i.e. MEDM and its friends. I also
installed the cool Tortoise SVN client which lets you interact with SVN repositories through
the windows explorer shell. (The right-click menu now contains SVN options.) I checked out
the MEDM directory from the 40m SVN onto the desktop. You should be able to just right-click in
that window and choose "SVN Update" to get all the newest screens that have been contributed to
SVN; however, there are currently some problems with the 40m SVN that make that not go smoothly.

At the moment on Andrey's (Windows) machine you can go into the MEDM folder and double-click on
any screen and it will just work, with the exception that not all the screens are installed
due to SVN difficulties.
  500   Tue May 27 16:24:54 2008 tobinConfigurationComputer Scripts / Programsndsproxy
The NDS Proxy is a program that accepts NDS (LIGO Network Data Server) connections from the internet and relays them to
our internal frame-builder, so that you can get DAQ and test-point channel data from off-site.

I stopped the ndsproxy that was running on rana and started it on nodus, its new home. This will be
documented in the wiki.

So far I haven't found a mechanism by which the ndsproxy was restarted automatically on rana. Has it just been
restarted by hand?

The ndsproxy stuff lives in target/ndsproxy. Restarting it seems to be just a matter of running "start_ndsproxy" in
that directory.
  508   Fri May 30 21:30:15 2008 tobinConfigurationComputerssvn on solaris
I installed svn on op440m.  This involved installing the following packages from sunfreeware:

apache-2.2.6-sol9-sparc-local  libiconv-1.11-sol9-sparc-local   subversion-1.4.5-sol9-sparc-local
db-4.2.52.NC-sol9-sparc-local  libxml2-2.6.31-sol9-sparc-local  swig-1.3.29-sol9-sparc-local
expat-2.0.1-sol9-sparc-local   neon-0.25.5-sol9-sparc-local     zlib-1.2.3-sol9-sparc-local
gdbm-1.8.3-sol9-sparc-local    openssl-0.9.8g-sol9-sparc-local

The packages are located in /cvs/cds/caltech/apps/solaris/packages.  The command line to install
a package is "pkgadd -d " followed by the package name.  This can be repeated on nodus to get
svn over there.  (Kind of egregious to require an apache installation for the svn _client_, I 
know.)
  510   Sun Jun 1 19:39:35 2008 tobinConfigurationComputerselog, etc
Phil Ehrens gave me a DVD of the 40m elog, apache, and (Jamie's) SVN archive.
I copied it to nodus:/home/controls/dvd-from-ehrens.  Once we get the elog
running on nodus, we can copy the datafile over again from dziban (so that
we don't lose any elog entries) and switch over.
  513   Tue Jun 3 10:19:45 2008 tobinConfigurationComputersbig machine
Several of us transported the big new awesome Sun box from Bridge over to
the 40m last week. If I recall correctly, it's a SunFire X4600 with
something like sixteen 64-bit AMD processor cores at 2.8 GHz. It sounds
like a jet engine when it starts up (before the cooling fans are throttled
back) and has four power supplies (each with its own connection
to the wall). It has slick removable hard disks and fan units too. Our
working name for it is "megatron".

Anyway. It came with two hard disks, one with Solaris 10 installed. I took
the other hard disk over to Alex, who copied a Realtime Linux installation
onto it. Alex says it boots and runs fine.

It remains for you guys to install the machine onto rails and install the
whole thing into a rack. Before it goes into service as a realtime control
machine, you might as well install Matlab on it and do some heavy-duty
computation.

  514   Tue Jun 3 10:40:27 2008 tobinConfigurationComputersnew dataviewer
Alex let me know the secret location of the latest dataviewer executable for Linux. It is:

http://www.ligo.caltech.edu/~aivanov/upload/dv/Control/dc3

If your linux dataviewer on linux2 has the "year field not filled in" bug, you should download this into /usr/local/bin/dc3 (after making a backup of that file).

It looks like there's no dataviewer installed on rosalba yet. We should figure out a better directory layout for the linux machines; currently dataviewer is installed locally on linux2. It should be in /cvs/cds/caltech/apps/linux/something so that all the linux machines see the same installation.
  636   Sun Jul 6 16:17:40 2008 tobinHowToComputersSVN
I was able to check out the 40m SVN here in Livingston using this command:

svn co svn+ssh://controls@nodus.ligo.caltech.edu/cvs/cds/caltech/svn/trunk/medm

As you might guess, this uses ssh in place of the web server (which we don't have yet).
  68   Tue Nov 6 14:51:03 2007 tobin, robUpdateIOOMode cleaner length
Using the Ward-Fricke variant* of the Sigg-Frolov method, we found the length of the mode cleaner to be 27.0934020183 meters, a difference of -2.7mm from Andrey, Keita, and Rana's measurement on August 30th.

The updated RF frequencies are:
3  fsr =  33 195 439 Hz
12 fsr = 132 781 756 Hz
15 fsr = 165 977 195 Hz
18 fsr = 199 172 634 Hz
* We did the usual scheme of connecting a 20mVpp, 2 kHz sinusoid into MC AO. Instead of scanning the RF frequency by turning the dial on the 166 MHz signal generator ("marconi"), we connected a DAC channel into its external modulation port (set to 5000 Hz/volt FM deviation). We then scanned the RF frequency from the control room, minimizing the height of the 2 kHz line in LSC-PD11. In principle one could write a little dither servo to lock onto the 15fsr, but in practice simply cursoring the slider bar around while watching a dtt display worked just fine.
  16183   Fri Jun 4 17:46:25 2021 unYehonathanUpdateCDSOpto-isolator for c1auxey

I mounted the optoisolator on the DIN rail and connected the 3 first channels

C1:SUS-ETMY_UL_ENABLE
C1:SUS-ETMY_UR_ENABLE

C1:SUS-ETMY_LL_ENABLE

to the optoisolator inputs 1,3,4 respectively. I connected the +15V input voltage into the input(+) of the optoisolator.

The outputs were connected to DB9F-2 where those channels were connected before.

I added DB9F-1 to the front panel to accept channels from the RTS. I connected the fast channels to connectors 1,2,3 from DB9F-1 to DB9F-2 according to the wiring diagram. The GND from DB9F-1 was connected to both connector 5 of DB9F-2 and the output (-).

I tested the channels: I connected a DB9 breakout board to DB9F-2. I measured the resistance between the RTS GND and the isolated channels while switching them on and off. In the beginning, when I turned on the binary channels the resistance was behaving weird - oscillating between low resistance and open circuit. I pulled up the channels through a 100Kohm resistor to observe whether the voltage behavior is reasonable or not. Indeed I observed that in the LOW state the voltage between the isolated channel and slow GND is 15V and 0.03V in the HIGH state. Then I disconnected the pull up from the channels and measured the resistance again. It showed ~ stable 170ohm in the HIGH state and an open circuit in the LOW state. I was not able to reproduce the weird initial behavior. Maybe the optoisolator needs some warmup of some sort.

 

We still need to wire the rest of the fast channels to DBF9-3 and isolate the channels in DBF9-4. For that, we need another optoisolator.

 

There is still an open issue with the BI channels not read by EPICS. They can still be read by the Windows machine though.

Attachment 1: 20210604_173420.jpg
20210604_173420.jpg
  3038   Wed Jun 2 18:36:20 2010 valeraDAQCDSNoise generators in LSP

Alex wrote a new code to implement LSP noise generator. The code is based on 64 bit random number generator from Numerical Recipes 3rd ed ch 7.1 (p 343).

Joe made two instances in the LSP model.

The attached plot shows the spectra and coherence of two generators. The incoherence is ~1/Navg - statistically consistent with no coherence.

Attachment 1: noisegenerators.pdf
noisegenerators.pdf
  3048   Thu Jun 3 22:33:31 2010 valeraSummaryCDSsimulated plant work

 I put matlab files and a summary into the 40m wiki for the fitting of the 40m Optickle transfer functions and generating digital filters for the simulated plant:

http://lhocds.ligo-wa.caltech.edu:8000/40m/Generating_DOF-%3EPD_digital_filters_based_on_Optickle_modeling

The filters are not loaded yet. Joe and Alex will make a rcg code to make a matrix of filters (currently 5x15=75 elements) which will enable the simulated plant tf's.

Joe and I tried to put a signal through the DARM loop but the signal was not going through the memory location in the scx part of the simulated plant.

 

Edit by Joe:

I was able to track it down to the spx model not running properly.  It needed the Burt Restore flag set to 1.  I hadn't done that since the last rebuild, so it wasn't actually calculating anything until I flipped that flag.  The data is now circulating all the way around.  If I turn on the final input (the same one with the initial 1.0 offset), the data circulates completely around and starts integrating up.  So the loop has been closed, just without all the correct filters in.

  3070   Fri Jun 11 22:09:58 2010 valeraHowToCDSfoton

 It appears that foton does not like the unstable poles, which we need to model the transfer functions.

But one can try to load the filters into the front end by generating the filter file e.g.:

#
# MODULES DARM_ASDC
 
#
################################################################################
### DARM_ASDC                                                                   ###
################################################################################
# SAMPLING DARM_ASDC  16384
# DESIGN   DARM_ASDC  
### ####
DARM_ASDC  0 21 6  0  0 darm 1014223594.005454063416 -1.95554205062071  0.94952075557861 0.06176931505784 -0.93823068494216
                         -2.05077577179611   1.05077843532639  -2.05854170261687  1.05854477394411
                         -1.85353637553024   0.86042048250739  -1.99996540107622  0.99996542454814 
                         -1.93464836371852   0.94008893626414  -1.89722830906561  0.90024221050918
                         -2.04422931770060   1.04652211283968  -2.01120153956052  1.01152717233685 
                         -1.99996545575365   0.99996548582538  -1.99996545573320  0.99996548582538

 

 

 

Unfortunately if you open and later save this file with foton it will strip the lhp poles.

  3074   Sun Jun 13 08:28:44 2010 valeraUpdateLocking40m Upgrade Optickle Model

 In my calculation of the digital filters of the optical transfer functions the carrier light is resonant in coupled cavities and the sidebands are resonant in recycling cavities (provided that macroscopic lengths are chosen correctly which I assumed).

  3558   Sat Sep 11 22:42:07 2010 valeraUpdatePSLPSL update

- The PMC REFL PD was moved from the temporary location to the one called for by the PSL layout (picture attached). The leakage beams were dumped.

- The FSS reference cavity was aligned using temporary periscope and scanned using NPRO temperature sweep. The amplitude of the sweep (sine wave 0.03 Hz) was set such that the PMC control voltage was going about 100 V p-p with. With rough alignment the visibility was as high as 50% - it will be better when the cavity is locked and better aligned but not better than 80% expected from the mode astigmatism that Tara and I measured on Thursday. The astigmatism appear to come from the FSS AOM as it depends on the AOM drive. We reduced the drive control voltage from 5 V to 4V beyond that the diffraction efficiency went below 50%. The FSS REFL PD was set up for this measurement as shown in the attached picture. There is also a camera in transmission not shown in the picture.

Attachment 1: DSC_2502.JPG
DSC_2502.JPG
Attachment 2: DSC_2505.JPG
DSC_2505.JPG
ELOG V3.1.3-