| ID |
Date |
Author |
Type |
Category |
Subject |
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196
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Tue Dec 18 16:50:35 2007 |
tobin | Update | SAFETY | uvex 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
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| Attachment 2: bad-glasses-zoom.jpg
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195
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Tue Dec 18 00:51:39 2007 |
Andrey | Update | Computer Scripts / Programs | Results of Saturday overnight measurements |
As I indicated in the previous e-log entry (#194), I made overnight measurements in XARM in the night from Saturday to Sunday.
Root-mean-square values of the peaks in calibrated spectra were calculated, and I plotted them as functions of suspension gains in ITMX and ETMX "position" degrees of freedom.
More specifically, Q_ITMX means the value in the channel "C1:SUS-ITMX_SUSPOS_GAIN", while Q_ETMX means the value in the channel "C1:SUS-ETMX_SUSPOS_GAIN".
Root-mean-square values (RMS) were calculated during that night in three intervals:
1) around 0.8 HZ in the interval (0.6 Hz <-> 1.0 Hz);
2) around 3.0 Hz in the interval (2.0 Hz <-> 3.6 Hz);
3) in the broad interval from 0.6Hz to 3.6Hz.
I plotted three results for RMS in the abovementioned three intervals in three different ways:
1) view from the top in the axes (Q_{ITMX}+Q_{ETMX})/2 and (Q_{ITMX}-Q_{ETMX}) -> first three graphs (attachments 1 -3);
2) view from the side in the same sum- and difference-axes -> next three graphs (attachments 4-6);
3) view from the side in Q_{ITMX} and Q_{ETMX} axes -> next three graphs (attachments 7-9), above accelerometer spectra (attachments 10-11).
Also, I compared the ground noise level by comparing spectra of accelerometer signals at different times during that night. As a reminder, before my disease I installed one accelerometer near ITMX and another accelerometer near ETMX (see entries 161 and 172 in ELOG). The plots of ratios of accelerometer signals at different times (pairs of times that were used: 12AM and 3AM, 12AM and 6AM, 12AM and 9AM) are given below, see attachments 10-11.
Tomorrow I will try to compare the results with the second measurements that are being taken tonight. |
| Attachment 1: RMS_08Hz_top_view.png
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| Attachment 2: RMS_3Hz_top_view.png
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| Attachment 3: RMS_broad_top_view.png
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| Attachment 4: RMS_08Hz_Qsum-Qdiff-axes.png
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| Attachment 5: RMS_3Hz_Qsum-Qdiff-axes.png
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| Attachment 6: RMS_broad_Qsum-Qdiff-axes.png
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| Attachment 7: RMS_08Hz_Qaxes.png
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| Attachment 8: RMS_3Hz_Qaxes.png
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| Attachment 9: RMS_broad_Qaxes.png
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| Attachment 10: Accel_ITMX.png
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| Attachment 11: Accel_ETMX.png
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194
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Mon Dec 17 23:42:08 2007 |
Andrey | Configuration | Computer Scripts / Programs | Overnight measurements in X-arm |
I am making overnight measurements this night (from Monday to Tuesday) in XARM.
The X-arm is now locked, and the values for suspension damping gain will be changed in the interval from 1 to 7 with the step 0.5 in both ITMX and ETMX.
This is the second, repeated measurement. The results of the first measurement from Saturday to Sunday night will be reported in the separate ELOG entry (sorry, I did not make an ELOG entry on Saturday evening about running the program overnight).
The very first attempt to run the script in the night from Thursday to Friday was not successful. |
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193
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Mon Dec 17 11:47:13 2007 |
alberto | Update | Electronics | an alternative design for the RFAM monitor's filter at 33Mhz |
| Since the Butterworth turned out o be rather wide-band, I tried an other configuration for the 33 MHz filter. Attached are the simulated transfer function and the measured. As one can see, the measured peak is much broader than expected. |
| Attachment 1: RFSim99-33MHz.png
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| Attachment 2: RF99-SimmButterworthPrototype.png
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| Attachment 3: RFSim99-33MHz-TFplot.png
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192
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Sun Dec 16 16:52:40 2007 |
dmass | Update | Computers | Computer on the end Fixed |
I had Mike Pedraza look at the computer on the end (tag c21256). It was running funny, and turns out it was a bad HD.
I backed up the SURF files as attachments to their wiki entries. Nothing else seemed important so the drive was (presumably) swapped, and a clean copy of xp pro was installed. The username/login is the standard one.
Also - that small corner of desk space is now clean, and it would be lovely if it stayed that way. |
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191
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Thu Dec 13 23:56:02 2007 |
Andrey | Configuration | Computer Scripts / Programs | Overnight measurements |
After my disease (fever, vomitting, nose problem, overall weakness) I returned to LIGO today for the first time after the weekend, and I am running the script for the XARM-measurements over this night.
So, suspension dumping gains should undergo changes in the interval from 1 to 10 in both ITMX and ETMX.
XARM has been of course locked.
I started running the script for the first time at about 10PM, but I realized after an hour and a half that my step of gain increase 0.2 was too shallow, too small to execute my program during one night. Therefore, I needed to terminate the program, change my program so that it increases the gain with increment 0.5, not 0.2, and started it again around midnight.
Going home.
P.S. The red pump that I borrowed from the lab (Steve's pump?) is back at its previous place. The tire-worker tells me that I absolutely need to change all four tires for almost 500 dollars. I regret a lot about that huge money loss. |
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190
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Thu Dec 13 12:05:36 2007 |
alberto | Omnistructure | Electronics | The new Butterworth seems to work quite well |
It works better probably because of the small inductors I'm using this time.
The peak is at 30 MHz because I didn't have the precise elements to get 33.
The bandwidth and the Q could be improved by adding one or two more order to the filter and trying to better match the low-pass' resonant frequency with the high-pass'.
Also I have to see if it could work at 166 and 199 MHz as well. |
| Attachment 1: TF_New_Butterworth_12-Nov-2007_TF.png
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| Attachment 2: Bultervverth2.png
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189
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Wed Dec 12 22:24:48 2007 |
tobin | Frogs | PEM | weather 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. |
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188
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Wed Dec 12 16:22:22 2007 |
alberto | Omnistructure | Electronics | LC filter for the RF-AM monitor circuit |
In the LC configuration (see attached schematic) the resonant frequency is tuned to one of the peak of our RF-AM monitor and it is amplified by a factor equal to the Q of the filter. As I wrote in one of the last elog entries, we would like amplifications of about 10-30 dB in order to have negligible couplings. Such values are obtained only with small capacitances (few or less pF). The drawback is relatively large inductance (uH or more) which has inevitably low Self Resonant Frequencies (SRF - the resonant frequencies of the RLC circuit usually associated with an actual inductor - ~ MHz). Even before, one limit is also the input impedance of the RF amplifier. Quality factors > 1 require megaohms, far from the 50 ohms in the MiniCircuit amplifiers I’m using now. So, if we plan to use these even for the final design of the circuit, we have to abandon the LC configuration.
For this same reason the only way I could get the expected responses from my several test boards was with a 10 megaohm input probe (see attachment for the measurement with and without probe). Assuming that impedance, I found these as the best trade-offs between the attenuation requirements and the values of the inductors for respectively the peaks at 33, 66,133, 166,199 MHz:
26uH, 6.6u, 20u, 73u, 16u
If we could find inductor with these values and high SRF the configuration should work. The problem is I couldn’t find any. Above a few uH they all seem to have SRF ~ MHz.
That is why I switched to the Butterworth. This should work despite the input impedance of the amplifier and with much smaller inductances. I made a totally new test circuit, with surface mount components. I think I still have to fix some things in the measurements but (this time I got rid of the simulator I was using earlier and designed a new configuration with new values from the Horowitz’s tables) it seems I have the expected peaks. More soon. |
| Attachment 1: TF_LC_filter_10pF_1.8uH_scope_probe.png
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| Attachment 2: TF_LC_filter_10pF_1.8mH_no_probe.png
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| Attachment 3: LC_filter_schematic.png
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187
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Mon Dec 10 20:35:59 2007 |
tobin | Configuration | Computer Scripts / Programs | autolocking 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 $$ > /dev/null
then
echo Another copy of this program is already running. Exiting!
exit 1
fi This code searches for all processes with the same name as this script ($0) and then use grep to exclude (-v) the current process ID ($$). |
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186
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Mon Dec 10 19:08:03 2007 |
tobin | Configuration | PSL | MZ |
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. |
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185
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Mon Dec 10 18:42:20 2007 |
tobin | Update | PSL | ISS 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
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184
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Mon Dec 10 13:54:26 2007 |
rob | HowTo | Computer Scripts / Programs | Don't blame the Matlab compiler |
For human error. We should be careful to only run the compiler outside the mDV directory (thus placing the _mcr outside of the range the addpath command in the mdv_config files). Or maybe there's a smarter solution... |
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183
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Fri Dec 7 19:14:30 2007 |
tobin | Update | PSL | ISS 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. |
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182
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Fri Dec 7 18:31:30 2007 |
tobin | Update | Computer Scripts / Programs | compiled 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. |
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181
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Fri Dec 7 18:28:30 2007 |
tobin | Update | Computer Scripts / Programs | compiled 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. |
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180
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Fri Dec 7 14:14:48 2007 |
rob | Metaphysics | Computer Scripts / Programs | tdsread problems on Solaris |
tdsread has developed a strange new illness, whereby it cannot read EPICS values from two subsystems at once (e.g., getting an LSC and SUS value simultaneously). I thought this might have something to with the fact that both losepics and iscepics are running on the same box,
but the same thing happens with IOO EPICS records, so that's not the culprit.
This is new behaviour, and it's only happening on the solaris machines. I suspect some ENV/cshrc juju has caused it, as the tdsread executable is the same one from April, and I don't think our EPICS infrastructure has changed otherwise. In the near term we can either try running the scripts on linux, or modify the IFO scripts to not do these types of calls. |
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179
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Fri Dec 7 11:33:24 2007 |
waldman | Omnistructure | OMC | PZT wiring |
The 2 pin LEMO connector has got an unmarked pin and a pin marked by a white half-circle.
The unmarked pin is connected to the side of the PZT attached to the mirror.
The marked pin is connected to the side of the PZT attached to the tombstone. |
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178
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Fri Dec 7 00:02:26 2007 |
rana | Summary | IOO | MC/FSS Frequency Noise |
The FSS frequency noise is not very bad.
I compared the MC_F spectra between Hanford and the 40m using DTT and its 'User NDS' option.
After Sam, Jenne, and DavidM installed the new MC Servo some time ago, the MC_F spectrum here
has had some whitening before it goes into the DAQ (on board; same as LLO & LHO). The tuning
coefficient of the VCO is also basically the same between all PSLs since everyone has the same
chip in the VCO driver.
Therefore, at the frequencies where the MC gain is more than ~4, the MC_F signal calibration is
the same here as anywhere. Since its the servo control signal, its basically a measure of the
frequency noise incident on the MC -- its just what comes out of the FSS with the table noise on
top. At low frequencies (< 100 Hz) its a measure of the motion of the MC mirrors.
Above 200 Hz ours is the same as theirs; except for the enormous power line spikes. I think that's
either all on the light. But our acoustics are better and the noise above 1 kHz levels off at the
same flat floor (the phase noise of the VCO) as H1. The huge lump around 100 Hz is the MC2 DAC noise and
it goes down to the H1 levels when we flip on the dewhites. The giant excess from 5-50 Hz is just the fact
that our stacks don't do much until 20-30 Hz.
So we can stop blaming the FSS and move on with life as soon as Tobin gets the ISS back in shape. |
| Attachment 1: fly.pdf
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177
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Thu Dec 6 19:30:43 2007 |
tobin | Update | PSL | ISS 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
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176
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Thu Dec 6 19:19:47 2007 |
Andrey | Configuration | SUS | Suspension damping Gain was restored |
Suspension damping gain was disabled for some reason (all the indicators in the most right part of the screen C1SUS_ETMX.adl were red), it is now restored. |
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175
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Thu Dec 6 18:11:15 2007 |
rob | HowTo | Computer Scripts / Programs | Making DMF monitors |
I was able to use the matlab compiler to compile a version of the linetracker written by Rana, and run the compiled version on mafalda.
I believe I made the necessary edits to our mDV config file so that it should be easy for others to follow these steps:
1) Write the DMF routine you want, as a matlab function (not a script).
2) If it runs correctly in matlab, then from the matlab command line compile
it using the -m flag (i.e., mcc -m myfun.m). You should run the
compiler from the directory where you want the executable to end up (don't use the mDV/extra
directory so it doesn't get all cluttered).
3) prior to running the resulting executable (which should be called simply myfun),
prepend the directories
/cvs/cds/caltech/apps/linux/matlab/bin/glnx86
/cvs/cds/caltech/apps/linux/matlab/sys/os/glnx86/
to the LD_LIBRARY_PATH enviroment variable. These directories must be prepended as the
versions that already exist in /usr/lib don't work; I'm loathe to do this in the cshrc.40m
for fear of later conflicts, so it will need to be done in some sort of shell script which
calls the matlab executable.
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174
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Thu Dec 6 15:22:42 2007 |
Andrey | Summary | Electronics | Pictures of the inside of He-Ne laser |
Steve gave me an old "dead" He-Ne laser that long time ago was used for ETMX optical lever.
I dismantled it (cutting the metallic enclosure with a metallic saw), and these are two pictures of what is inside. |
| Attachment 1: DSC_0226.JPG
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| Attachment 2: DSC_0228.JPG
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173
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Thu Dec 6 15:21:59 2007 |
alberto | Frogs | Electronics | RF Transfer Function of Stiff Aluminum Wires |
| Transfer function of 3cm long Aluminum wires and of 3cm stranded wires |
| Attachment 1: TF_3cm_stiff_wires.amplitude.png
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| Attachment 2: DSC_0225compressed.JPG
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| Attachment 3: TF_3cm_stranded_wires.amplitude.png
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172
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Wed Dec 5 23:19:03 2007 |
Andrey | Configuration | PEM | Accelerometers are turned on |
All accelerometers have been turned on, as Alan asked during Wednesday meeting.
Typical power spectra and coherence plots are attached below.
"East" in the name means that the previous location of accelerometrs was to the east from "Beamsplitter" (the location for "east" accelerometers was not changed, actually, it is still near ITMX), while "west" means that previously accelerometers were to the west from the BS, but now their new location is near the ETMX.
I will change the names of the channels tomorrow (Thursday) when someone (Tobin?) will show to me how to do it.
P.S. (addition made on Dec. 19th, 2007, by Andrey) I intended to change the names of accelerometers the next day, Thursday Dec. 06,
but I did not do it that day (did not understand how to do it), then I fell ill, and eventually
I changed the names of accelerometers on December 19th, see entry to ELOG #204) |
| Attachment 1: Power_Sp_and_Coh_XY-EAST.pdf
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| Attachment 2: Coherence-ZX_East.pdf
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| Attachment 3: Coherence-ZY_East.pdf
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| Attachment 4: Power_Sp_WEST.pdf
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| Attachment 5: Coherence-ZX_West.pdf
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| Attachment 6: Coherence-XY_West.pdf
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| Attachment 7: Coherence-YZ_West.pdf
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171
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Wed Dec 5 20:32:51 2007 |
tobin | Update | PSL | ISS 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.  |
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170
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Wed Dec 5 19:25:07 2007 |
rana | DAQ | CDS | DMF |
I made a database file on C1AUX called dmf.db. It has 9 DMF EPICS channels which are also trended
so that one can now write data to those channels from a DMF Monitor and the data will be records.
New channels:[C1:DMF-SEIS_1]
[C1:DMF-SEIS_2]
[C1:DMF-SEIS_3]
[C1:DMF-LINE_1]
[C1:DMF-LINE_2]
[C1:DMF-LINE_3]
[C1:DMF-MC_1]
[C1:DMF-MC_2]
[C1:DMF-MC_3]
I added these to C1AUX because it doesn't do much and can be booted without having much effect.
(it controls Mech Shutters, Video, and Illuminators. It used to also do the EO Shutter but I
removed that from its startup.cmd and it will no longer load those records). |
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169
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Wed Dec 5 18:22:03 2007 |
tobin | Update | PSL | ISS 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
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168
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Wed Dec 5 18:08:36 2007 |
Andrey | Update | ASC | Optical Lever laser for ETMX is installed |
A new laser with \lambda=633nm has been intalled and the mirror adjusted so that the signal hits the center of the photodetector.
Output power level of that laser is 3.45 +- 0.05 mW.
Only about 0.29mW hits the photodetector.
Cable clips have been used to firmly fix the power supply cable for the laser.
See attached photopicture of the ETMX - "oplev" - optical - table. |
| Attachment 1: DSC_0199.JPG
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167
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Wed Dec 5 17:49:57 2007 |
tobin | Update | PSL | ISS |
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
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166
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Wed Dec 5 16:57:36 2007 |
tobin | HowTo | Computer Scripts / Programs | SR785 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. |
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165
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Wed Dec 5 13:49:08 2007 |
alberto | Update | Electronics | RF AM PD lines monitor |
In the last weeks I’ve been working on the design of an electronic board to measure directly the power of the main spectral lines on of the RF-AM photodiode from as many independent outputs. The idea is to have eventually a monitor channel in the CDS network for the power of each line.
Looking at at the spectrum from the RF-AM PD (see attached plot), there are 5 main lines:
Frequency
3 fsr = 33 195 439 Hz
4 fsr = 66 390 878 Hz
12 fsr = 132 781 756 Hz
15 fsr = 165 977 195 Hz
18 fsr = 199 172 634 Hz
Two main approaches have been proposed for the circuit depending on the way followed to isolate the lines:
1) Filters: the frequencies are separated by narrow notch filters, then a diode bridge rectifies and a low pass filter extracts the DC component.
2) Mixers: for each frequency there is a mixer driven by a copy of the correspondent modulation frequency provided by the function generators (the Marconi). The mixers automatically give the DC component of the rectified signals.
Because of the phase lags that we should compensate if we used mixers, we would prefer the first approach, if it works.
Starting with a tolerance of about 10% between the channels, the spectrum (see attachment) sets the constraint to the filter’s suppression:
Filter central frequency [MHz]******Suppression within 30 Mhz [dB]
33*********************************-7-20 = -27
66**********************************7-20 = -13
133*********************************12-20 = -8
166********************************-12-20 = -32
199*********************************10-20 = 10
So far I’ve tried two kinds of designs for the filters, Butterworth (see attachment) and LC and I'm measuring transfer functions tuning the components to match the central frequency and the bandwdth of the filters with the requirements.
The frequencies we’re dealing with are rather high and several adjustments had to be done to the measurement system in order to shield the circuit from the impedance of the input and the output line (i.e., amplifier turned out to be necessary). Also, an the mixer had to be replaced to an RF one.
It seems I'm now measuring new transfer functions (which look quite different from what I've got with no amplifiers).
To be posted soon. |
| Attachment 1: alberto.spectrum2.png
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| Attachment 2: Butterworth.PNG
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164
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Wed Dec 5 10:57:08 2007 |
alberto | HowTo | Computers | Connecting the GPIBto USB interface to the Dell laptop |
| The interface works only on one of the USB ports of the laptop (the one on the right, looking at the computer from the back). |
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163
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Tue Dec 4 23:16:35 2007 |
tobin | Update | PSL | ISS |
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. |
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162
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Mon Dec 3 22:20:09 2007 |
tobin | Configuration | PSL | ISS |
| 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. |
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161
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Mon Dec 3 19:44:58 2007 |
Accelerometers on new mounts | Configuration | PEM | Andrey |
I (Andrey) continued today working with new accelerometer mounting. (see entry #151 about my Friday work).
I bought screws/washers and attached those mounts with accelerometers to metallic frames which are firmly cemented to the floor.
One such mount with three accelerometers (in X-, Y-, Z-directions) is installed near the ITMX (in the previous location, but NOT on top of the unused stack as before Friday), the other mount with three accelerometers in three orthogonal directions is installed near ETMX in the east end of the room (this set of accelerometers was installed between MC and BS before Friday). I uncoiled the cables, put them into the cable tray towards the ETMX, and hooked-up the three accelerometers near ETMX in the east end of the room.
Now all six accelerometers are hooked-up (that is, connected to power supply board with cables).
We decided with Steve Vass to put red cones (similar to those that are on highways in the road construction zones) in order to prevent people from bumping into accelerometers. Please use caution when walking along the X-arm.
I took several pictures of the new accelerometer setup. Picture "DSC_0194.JPG" shows the mount with accelerometers near the the ITMX and the beamsplitter chamber,
picture "DSC_0195.JPG" is the "zoomed-in" view of the same accelerometers, while picture "DSC_0196.JPG" shows the mount with accelerometers near ETMX in the east end of the room.
Many thanks to Mr. Steve Vass for his thorough explanation/showing me how to drill the metal and put threads in the holes. |
| Attachment 1: DSC_0194.JPG
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| Attachment 2: DSC_0195.JPG
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| Attachment 3: DSC_0196.JPG
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Mon Dec 3 19:06:49 2007 |
rana | DAQ | Computer Scripts / Programs | linemon |
I turned up my nose at Matlab's special tools. I modified the linetracker to use the
relationship phase = 2*pi*f*t to estimate the frequency each minute. The
code uses 'polyfit' to get the mean and trend of the unwrapped phase and then determines
how far the initial frequency estimate was off. It then uses the updated number as the
initial guess for the next minute.
I looked at a couple hours of data before letting it run. It looks like the phase of the
'60 Hz' peak varies at 20 second time scales but not much faster or rather anything faster
would be a glitch and not a monotonic frequency drift.
From the attached snapshot you can see that the amplitude (PZT1_PIT) varies by ~10 %
and the frequency by ~40 mHz in a couple hour span. |
| Attachment 1: spd64d1.jpg
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Mon Dec 3 17:55:39 2007 |
tobin | HowTo | Computer Scripts / Programs | linemon |
| 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. |
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Mon Dec 3 16:24:47 2007 |
tobin | HowTo | Computers | GNU 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. |
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Mon Dec 3 00:10:42 2007 |
rana | DAQ | Computer Scripts / Programs | linemon |
I've started up one of our first Matlab based DMT processes as a test.
There's a matlab script running on Mafalda which is measuring the height of the 60 Hz peak
in the MC1 UL SENSOR and writing it to an unused EPICS channel (PZT1_PIT_OFFSET).
The purpose of this is just to see if such a thing is stable over long periods of time. Its
open on a terminal on linux3 so it can be killed at any time if it runs amok.
Right now the code just demods the channel and tracks the absolute value of the peak. The
next upgrade will have it track the actual frequency once per minute and then report that
as well. We also have to figure out how to make it a binary and then make a single script
that launches all of the binaries.
For now you can watch its progress on the StripTool on op540m; its cheap and easy DMT viewer. |
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Sun Dec 2 21:13:16 2007 |
rana | Configuration | IOO | MC SUS re-alignment |
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| Attachment 1: e.png
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Sun Dec 2 21:07:39 2007 |
rana | Configuration | IOO | MC SUS re-alignment |
you asked for: diff 2007/12/01,4:58:48 2007/12/03,4:58:48 utc 'MC.*COMM'
LIGO controls: differences, 2007 12/01 04:58:48 utc vs. 2007 12/03 04:58:48 utc
__Epics_Channel_Name______ __Description__________ __value1____ __value2____
C1:SUS-MC1_YAW_COMM -0.273460 -0.503460
C1:SUS-MC2_PIT_COMM 3.624020 3.632020
C1:SUS-MC2_YAW_COMM -0.936800 -1.038800
C1:SUS-MC3_YAW_COMM -3.129000 -3.369000 |
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Sun Dec 2 21:02:12 2007 |
rana | Configuration | IOO | MC SUS re-alignment |
The spot on MC2 was not centered, so I put it back in the center:
- Made sure MC trans was high with the WFS off.
- Moved the Sliders on the MC Align screen until spot was centered (by eye)
- Moved some more until power was maximized.
- Unlock MC
- Center spots on McWFS
- Re-enable autolocker and McWFS loops.
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153
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Sun Dec 2 17:37:33 2007 |
rana | Omnistructure | Computers | Network Cabling in the Office |
We all know that we've spent many integrated man hours trying to figure out why our network connections
in the office area don't work. Usually its because of the bad hub around the Tobin/Osamu desk.
I pried open some of the wall conduit today and it looks pretty easy to fish cables through. I think
its time we finally did that. It may be a little disruptive, but I propose we get Larry to come over
and figure out what needs to happen for us to get regular 100 Mbit ports on the walls. These can
then all go over and get connected to a switch in the rack that holds linux1.
Opinions / comments ? |
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Fri Nov 30 21:27:24 2007 |
rana | DAQ | PEM | weather / stacis / c1pem1 |
I was trying to add some Seis BLRMS channels to the c1pem1 processor so that we could have DMT trends.
Then I found that none of the Weather channels have been working for a year or so. I could also not
telnet into it. I tried resetting it but no luck. There was no entry in the Wiki for it so I added
a place holder.
Have the weather channels ever worked? Do we have those sensors? I think I've never actually looked
for this. Seems like a fine ugrad job. |
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Fri Nov 30 20:17:26 2007 |
Andrey | Configuration | PEM | Accelerometers and alum.plates for them |
All 6 accelerometers which were located near the ITMX are turned off and disconnected from the power cords.
Actually these accelerometers are now in the office area on the electronics bench (to the left from Steve Vass' place).
I made today 4 new aluminum mounting plates for the accelerometers (I drilled holes and made threads in them). On Monday I will buy short screws and install accelerometers on these new mounting plates. These mounting plates will be screwed directly into the metallic frame which is firmly cemented to the ground. Before yesterday accelerometers were mounted on top of blue stack towers, not on the ground directly, so we hope that new measurements of the ground noise will be more realistic.
The 4 mounting plates are on the same desk -> on the electronics bench (to the left from Steve Vass' place). Please do not displace them.
Attached is a drawing of the aluminum mountain plate. |
| Attachment 1: Scheme_Aluminum_Piece-inches.pdf
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Fri Nov 30 20:13:57 2007 |
dmass | Summary | General | HeNe UniPhase Laser |
Data for the Uniphase 1.9 mW HeNe laser (labeled: "051507 From ISCT-BS") SN: 1284131 Model: 1103P
I used the Photon Beamscanner to obtain all data, then fit w(z) as shown on the plot with parameters w_0, z_R, and hidden parameter delta,
where z = delta + x, z is waist distance, x is distance from the laser.
Copies of the matlab code used to fit (/plot) are attached in .zip below. |
| Attachment 1: Matlabcode.zip
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| Attachment 2: UniPhaseWaist.jpg
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Fri Nov 30 19:46:58 2007 |
rana | Configuration | Computers | EPICS Time Bad again |
The time on the EPICS screens is off by 10 minutes again. Por Que?
Its because the ntpd on scipe25 wasn't restarted after the last boot. If someone
knows how to put the ntpd startup into that machine, please do so.
This time I started it up by just going sshing in as controls and then entering:
sudo /usr/sbin/ntpd -c /etc/ntp.conf
which runs it as root and points to the right file.
It takes a few minutes to get going because all of the martian machines have to first fail to
connect to the worldwide pool servers (e.g. 0.pool.ntp.org) before they move on and try linux1
which has a connection to the world. Once it gets it you'll see the time on the EPICS screens
freeze. It then waits until the ntp time catches up with its old, wrong time before updating
again.
According to the Wikipedia, this time is then good to 128 ms or less. |
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Fri Nov 30 19:29:14 2007 |
rana | Configuration | SUS | new screen |
Andrey is working on a new screen to show us the drift of the optics by alarming on
their osem values. You can find it under SUS as 'Drift Mon' from the site map.
To aid in this I ran the following csh commands which effect all optics:
foreach opt (ETMX ETMY ITMX ITMY MC1 MC2 MC3 BS PRM SRM)
foreach dof (POS PIT YAW)
ezcawrite C1:SUS-${opt}_SUS${dof}_INMON.PREC 0
end
end
This should make the DOF readouts more readable. |
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Fri Nov 30 19:11:05 2007 |
rana | Configuration | Electronics | ETMX oplev dead again |
I removed the ETMX HeNe and put in on a test table and it fired up fine. In its
previous location the light on the HeNe power supply was not lighting up. If
that's still on over the weekend we'l blame the power strip; the HeNe is a JDS
2.7 mW laser from 2002. |