ID |
Date |
Author |
Type |
Category |
Subject |
4793
|
Tue Jun 7 11:39:27 2011 |
Jamie | Update | SUS | No binary output module in ETMY |
Quote: |
1) The FM1 files in the XXSEN modules should switch the analog shadow sensor whitening. I found today that, at least on ETMY and ETMX, they do nothing. This needs to be fixed before we can use the suspensions.
|
Joe discovered today that ETMY in fact has no binary output module at all, so there is actually no digital control of the whitening filters at ETMY.
We suspect that the ETMY binary output module was maybe harvested to put in the LSC rack, but we're not sure.
We found a spare binary output adapter pcb, which I will try to assemble into a module to install in ETMY.
This does not explain what's going on with ETMX, though. ETMX has a binary output module, that appears to be properly hooked up. I'll try to debug what's going on there as well.
In the mean time, I've removed the ETMX binary output module to use as a reference for putting together another identical module for ETMY. |
4792
|
Mon Jun 6 23:56:16 2011 |
rana, valera | Configuration | SUS | ETMX/ETMY OSEM whitening |
We measured the OSEM PD whitening transfer function of the ETMX OSEM UL whitening stage (D000210) by comparing the input signal to the whitening amplifier (single pin LEMO monitor) to the output signal - both were piped into the DAQ. The transfer function was close to constant 0 dB/180 deg independent of the whitening switch selection (FM1 filter engaged/disengaged) up to ~20 Hz where we run out of coherence. All other ETMX and ETMY spectra at the input of the digital whitening compensation don't change when the whitening is switched on/off so by induction we conclude that all the ETMX/ETMY OSEM PD hardware whitening filters are not on. |
4791
|
Mon Jun 6 22:41:22 2011 |
rana | Update | SUS | Switching problem in SUS models |
Some weeks ago, Joe, Jamie, and I reworked the ETMY controls.
Today we found that the model rebuilds and BURT restores have conspired to put the SUS damping into a bad state.
1) The FM1 files in the XXSEN modules should switch the analog shadow sensor whitening. I found today that, at least on ETMY and ETMX, they do nothing. This needs to be fixed before we can use the suspensions.
2) I found all of the 3:30 and cts2um buttons OFF AGAIN. There's something certainly wrong with the way the models are being built or BURTed. All of our suspension tuning work is being lost as a consequence. We (Joe and Jamie) need to learn to use CONLOG and check that the system is not in a nonsense state after rebuilds. Just because the monitors have lights and the MEDM values are fluctuating doesn't mean that "ITS WORKING". As a rule, when someone says "it seems to work", that basically means that they have no idea if anything is working.
3) We need a way to test that the CDS system is working... |
Attachment 1: a.pdf
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4790
|
Mon Jun 6 18:29:01 2011 |
Jamie, Joe | Update | CDS | COMPLETE FRONT-END REBUILD (WITH PROBLEMS (fixed)) |
Today Joe and I undertook a FULL rebuild of all front end systems with the head of the 2.1 branch of the RCG. Here is the full report of what we did:
- checked out advLigoRTS/branches/branch-2.1, r2457 into core/branches/branch-2.1
- linked core/release to branches/branch-2.1
- linked in models to core/release/src/epics/simLink using Joe's new script (userapps/release/cds/c1/scripts/link_userapps)
- remove unused/non-up-to-date models:
c1dafi.md c1lsp.mdl c1gpv.mdl c1sup_vertex_plant_shmem.mdl
- modified core/release/Makefile so that it can find models:
--- Makefile (revision 2451) +++ Makefile (working copy) @@ -346,7 +346,7 @@ #MDL_MODELS = x1cdst1 x1isiham x1isiitmx x1iss x1lsc x1omc1 x1psl x1susetmx x1susetmy x1susitmx x1susitmy x1susquad1 x1susquad2 x1susquad3 x1susquad4 x1x12 x1x13 x1x14 x1x15 x1x16 x1x20 x1x21 x1x22 x1x23 #MDL_MODELS = $(wildcard src/epics/simLink/l1*.mdl) -MDL_MODELS = $(shell cd src/epics/simLink; ls m1*.mdl | sed 's/.mdl//') +MDL_MODELS = $(shell cd src/epics/simLink; ls c1*.mdl | sed 's/.mdl//') World: $(MDL_MODELS) showWorld:
- removed channel files for models that we know will be renumbered
- For this rebuild, we are also building modified sus models, that are now using libraries, so the channel numbering is changing.
- make World
- this makes all the models
- make installWorld
- this installs all the models
- Run activateDQ.py script to activate all the relevant channels
- this script was modified to handle the new "_DQ" channels
- make/install new awgtpman:
cd src/gds make cp awgtpman /opt/rtcds/caltech/c1/target/gds/bin
- turn off all watchdogs
- test restart one front end: c1iscex
BIG PROBLEM
The c1iscex models (c1x01 and c1scx) did not come back up. c1x01 was running long on every cycle, until the model crashed and brought down the computer. After many hours, and with Alex's help, we managed to track down the issue to a patch from Rolf at r2361. The code included in that patch should have been wrapped in an "#ifndef RFM_DIRECT_READ". This was fixed and committed to branches/branch-2.1 at r2460 and to trunk at r2461.
- update to core/branches/branch-2.1 to r2460
- make World && make installWorld with the new fixed code
- restarted all computers
- restart frame builder
- burt restored to 8am this morning
- turned on all watchdogs
Everything is now green, and things seem to be working. Mode cleaner is locked. X arm locked.
|
4789
|
Mon Jun 6 17:28:31 2011 |
steve | Update | Computers | still, no PEM channels |
Quote: |
AA filter box was removed and modified at 1Y7 today. The -5V power supply was current limited when I plugged it back in. It was removed for medical attention.
NO PEM channels available! because of this.
|
D68L8EX-850Hz filter chips were removed and bypassed-shorted as Rana's entry on March 17, 2006 in old elog.
This unit is still has a short somewhere. |
Attachment 1: P1070846.JPG
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4788
|
Mon Jun 6 17:22:09 2011 |
valera | Configuration | LSC | Clipping in the X arm 1064 um trans path |
I changed optics in the ETMX transmon path to remove clipping (which made a false QPD signal).
During the weekend I found that there was an offset in X arm c1ass pitch servo, which derives the signal by demodulating the arm cavity power, coming from the beam clipping in the transmon path.
The clipping was on the pair of the 1" mirrors that steer the beam after the 2" lens (see attached picture). The beam is about 5-6 mm in diameter at this distance from the lens and was not well centered.
I moved the steering mirrors downstream by about 8" where the beam is about 2-3 mm (the attached picture shows the mirrors in the new location). The Y arm layout is different from X arm and I didn't find any obvious clipping in transmon path.
The max X arm buildup went up from 1.3 to 1.5. I changed the TRX gain from -0.003 to -0.002 to obtain the normalized X arm power of 1 in this state. The MC refl DC is 1.6 out of 4.9 V and the Y arm buildup is ~0.9 so the TRX(Y) gains will have to be adjusted once the MC visibility is maximized. |
Attachment 1: XarmTransMon.pdf
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4787
|
Mon Jun 6 16:44:34 2011 |
Koji | Update | Electronics | POY11 tested |
The full characterization of POY11 is found in the PDF.
Resonance at 11.03MHz
Q of 7.6, transimpedance 1.98kOhm
shotnoise intercept current = 0.17mA (i.e. current noise of 7pA/rtHz)
Notch at 21.99MHz
Q of 56.2, transimpedance 35.51 Ohm
Notch at 55.20MHz
Q of 48.5, transimpedance 37.5 Ohm
|
Attachment 1: POY11_test.pdf
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4786
|
Mon Jun 6 02:09:39 2011 |
rana | Update | Electronics | POY11 Rework Nearly Complete |
I've finished tuning POY11 and it is now sitting on top of the analyzer waiting for Koji to test its noise.
Notes:
- R2 has been switched from a 50 -> 110 Ohm R and a (29 Ohm | 47 pF) in parallel to it. This makes the gain of the MAX4107 be ~20 above 100 MHz and ~5 around 11 MHz. The high gain at high frequency makes it stable (squashes the 200 MHz oscillation) and the low gain at low frequency is to prevent saturation (the raw 11 MHz transimpedance is too high).
- There are two notches: 22.12 MHz and 55.3 MHz.
- The TEST IN input has been disabled since it wasn't useful.
- 107 Ohms inserted into between the U11 output and the TSENSE feedthrough. This is to prevent oscillations when driving the long Dsub cable. This needs to be done on all Gold Box RFPDs.
- R4 -> 50 Ohms.
- Had trouble tuning this to get the resonance at 11.06 MHz. This turned out to be the parallel inductance coming from L3 (previously 1.45 uH) whereas we needed a total inductance of ~1.6 uH. So I changed L3 to 33 uH to get it to be negligible compared to 1.7 uH at 11 MHz. This needs to be considered for all the 11 MHz diodes.
|
Attachment 1: 777.png
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4785
|
Sat Jun 4 15:26:04 2011 |
Larisa Thorne | Update | Electronics | Seismometer Box Update |
(continuation of this)
Here are the transfer function and noise plots of the seismometer box, using the op amps that are actually indicated on the original plan (THS4131, AD826). I added them to the LISO op amp library (can be found in /cvs/cds/caltech/apps/linux64/liso/filter/opamp.lib)
Next step is to compare the noise graph below to the seismic noise curve of the interferometer to verify that the seismometer box configuration won't affect the curve... |
Attachment 1: SeisBoxLISO_transfer.pdf
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Attachment 2: SeisBoxLISO_noise.pdf
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4784
|
Fri Jun 3 18:12:03 2011 |
steve | Update | Computers | no PEM channels |
AA filter box was removed and modified at 1Y7 today. The -5V power supply was current limited when I plugged it back in. It was removed for medical attention.
NO PEM channels available! because of this.
|
4783
|
Fri Jun 3 14:27:32 2011 |
Koji | Update | Electronics | POP55 test results |
The full characterization of POP55 is found in the PDF.
Resonance at 54.49MHz
Q of 2.5, transimpedance 241Ohm
shotnoise intercept current = 4.2mA (i.e. current noise of 37pA/rtHz)
Notch at 11.23MHz
Q of 2.4, transimpedance 6.2 Ohm
Notch at 110.80MHz
Q of 53.8, transimpedance 13.03 Ohm
|
Attachment 1: POP55_test.pdf
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4782
|
Thu Jun 2 23:10:10 2011 |
Koji | Update | Electronics | REFL11 test results (Re: REFL11 fixed) |
The full characterization of REFL11 is found in the PDF.
Resonance at 11.062MHz
Q of 15.5, transimpedance 4.1kOhm
shotnoise intercept current = 0.12mA (i.e. current noise of 6pA/rtHz)
Notch at 22.181MHz
Q of 28.0, transimpedance 23 Ohm
Notch at 55.589MHz
Q of 38.3, transimpedance 56 Ohm
|
Attachment 1: REFL11_test.pdf
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|
4781
|
Thu Jun 2 16:31:41 2011 |
Jamie | Update | CDS | aquired SUS channel name suffixes changed from _DAQ to _DQ |
CDS changed the suffix for all aquired channel names from _DAQ to _DQ. When we rebuilt the sus models, described in the previous log, the channel names were changed and consequently the channel files were completely rewritten.
To fix the issue, the latest archived channel file was copied back into the chans directory, and the suffixes were changed, as so:
cd /opt/rtcds/caltech/c1/chans
cp archive/C1SUS_110602_155403.ini C1SUS.ini
sed -i 's/DAQ/DQ/g' C1SUS.ini
We then restarted the models and the framebuilder. |
4780
|
Thu Jun 2 16:23:42 2011 |
Jamie | Update | SUS | SUS control models updated to use new sus_single_control library part |
A new library part was made for the single suspension controller (it was originally made from the c1scx controller), using the following procedure:
- Opened c1scx model (userapps/trunk/sus/c1/models/c1scx)
- Cut ETMX subsystem block out of SUS subsystem
- Pasted ETMX block into new empty library, and renamed it C1_SUS_SINGLE_CONTROL
- Tweaked names of inputs, and generally cleaned up internals (cosmetically)
- Saved library to: userapps/trunk/sus/c1/models/lib/sus_single_control.mdl
Once the new sus_single_control library part was made and the library was committed to the cds_user_apps repo, I replaced all sus controller subsystems with this new part, in:
- c1scx
- c1scy
- c1sus (x5 for each vertex mass)
All models were rebuild, installed, and tested, and everything seems to be working fine. |
4779
|
Thu Jun 2 10:19:37 2011 |
Alex Ivanov | Summary | DAQ | installed new daqd (frame builder) program on fb (target/fb/daqd) |
I hope that new daqd code will fix the problem with non-aligned at 16 seconds frame file GPS times.
I have compiled new daqd program under /opt/rtcds/caltech/c1/core/release/build/mx and installed it under
target/fb/daqd, then restarted daqd process on "fb" computer. It was installed with the ownership of user root
and I did chmod +s on it (set UID on execution bit). This was done in order to turn on some code to renice daqd process
to the value of -20 on the startup. Currently it runs as the lowest nice value (high priority).
controls@fb /opt/rtcds/caltech/c1/target/fb $ ls -alt daqd
-rwsr-sr-x 1 root controls 6592694 Jun 2 10:00 daqd
Backup daqd is here:
controls@fb /opt/rtcds/caltech/c1/target/fb $ ls -alt daqd.02jun11
-rwxr-xr-x 1 controls controls 6768158 Feb 21 11:30 daqd.02jun11
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4778
|
Wed Jun 1 21:56:43 2011 |
Koji | Update | General | aLIGO BBPD / Green PD final result |
Here is the conclusive result for the circuit configuration for aLIGO BBPD and 40m Green PD.
- Use Mini-circuits MAR-6SM for the RF preamplifier. The 50Ohm input impedance is used for the RF transimpedance.
The maximum output is ~4dBm.
- Use Mini-circuits GALI-6 for the RF middle power amp. The gain is 12dB and the amplifier is linear up to +17dBm. i.e. This is still linear at the maximum output level of MAR-6SM.
- The total RF transimpedance is ~2k. The DC transimpedance is also 2k.
- The bandwidth is 80MHz with FFD100 and internal 25V bias. When S3399 is used, the bandwdith goes up to 180MHz
although the responsivity of FFD100 at 1064nm is better than S3399 by a factor of 1.5. At the 40m we will use S3399 for the green BB PD.
- By adding an LC network next to the PD, one of the unnecessary signal can be notched out.
As an example, 9MHz notch was placed for the FFD100 case.
- Noise level: ~10pA/rtHz as a floor noise level at around 30MHz. This corresponds to the equivalent dark current of 0.4mA.
Matt has finished the PCB layout. We will order small first batches, and stuff it for the test. Some of these will be the 40m green PD. |
Attachment 1: PD_response.pdf
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Attachment 2: linearity_GALI_6.pdf
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4777
|
Wed Jun 1 13:33:22 2011 |
koji, tara | Update | Electronics | TTFSS #7 |
We replaced GE81 by PZT2907A (PNP transistor) in TTFSS #7, it's working fine.
Last time I broke Q4 transistor, which is used in the low noise power module for TTFSS, (see the schematic) and could not find another PZT2907A, so GE81 was used temporarily. Now we changed it back to PZT2907A as designed. I tested it by checking the voltage outputs of the board. It works fine, all voltage outputs are correct. I labeled one of the slot on the blue cabinet tower and kept the rest of the transistors there.

Quote: |
I brought TTFSS set #7 to 40m and kept it in the electronic cabinet.
note that Q4 transistor has not been replaced back to PZT2907A yet. It's still GE82.
Q3 is now pzt3904, not PZT2222A.
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4776
|
Wed Jun 1 11:31:50 2011 |
josephb | Update | CDS | MC1 LR digital reading close to zero, readback ~0.7 volts |
There appears to be a bad cable connection somewhere on the LR sensor path for the MC1 optic.
The channel C1:SUS-MC1_LRPDMon is reading back 0.664 volts, but the digital sensor channel, C1:SUS-MC1_LRSEN_INMON, is reading about -16. This should be closer to +1000 or so.
We've temporarily turned off the LRSEN filter module output while this is being looked into.
I briefly went out and checked the cables around the whitening and AA boards for the suspension sensors, but even after wiggling and making sure everything was plugged in solidly. There was one semi-loose connection, but it wasn't on the MC1 board, but I pushed it all the way in anyways. The monitor point on the AA board looks correct for the LR channels, although ITMX LR struck me as being very low at about -0.05 Volts.
According to data viewer, the MC1 LR sensor channel went bad roughly two weeks ago, around 00:40 on 5/18 UTC, or 17:40 on 5/17 PDT.
UPDATE:
It appears the AA board (or possibly the SCSI cable connected to it) is the problem in the chain. |
4775
|
Tue May 31 17:30:42 2011 |
steve | Update | SUS | ETMY damping restored |
ETMY's watch dogs were found tripped. They were restored. |
4774
|
Tue May 31 16:07:57 2011 |
Larisa Thorne | Configuration | Electronics | Seismometer Box Update |
(Continuation of this)
I plugged the circuit into the LISO program to generate the graphs below....the first graph is a plot of frequency (f, in Hz) versus gain (in dB), and frequency (f, Hz) versus phase (in degrees). Also included is the second graph, which is a noise plot of all circuit parts which contribute to the total noise of the circuit.
The only issue I had was that two of the op amps I'd picked (see third attachment for the original circuit diagram) for the circuit were not in LISO's op amp library. So I replaced THS4131 (from the voltage buffer part) and AD826 (from the ADC driver part) with AD797 and LT1037, respectively in order to generate the plots below....
There are notes calling the AD797 "ultra low noise, low distortion", whose data sheet can be found here: AD797
Notes also call LT1037 "low noise, high speed precision op amp", whose data sheet can be found here: LT1037
I've put these in temporarily only, as I don't know if they are appropriate choices for the job or even if we have them. Suggestions? |
Attachment 1: SeisBoxLISOplot1.pdf
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Attachment 2: SeisBoxLISOplot2.pdf
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Attachment 3: STS2diagram_original.pdf
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4773
|
Tue May 31 15:45:37 2011 |
Jamie | Update | CDS | c1iscey IOchassis powered off for some reason. repowered. |
We found that both of the c1iscey models (c1x05 and c1scy) were unresponsive, and weren't coming back up even after reboot. We then found that the c1iscey IOchassis was actually powered off. Steve's accepts some sort of responsibility, since he was monkeying around down there for some reason. After powerup and reboot, everything is running again. |
4772
|
Tue May 31 14:29:00 2011 |
jzweizig | Update | CDS | frames |
There seems to be something strange going on with the 40m frame builder.
Specifically, there is a gap in the frames in /frames/full near the start of
each 100k second subdirectory. For example, frames for the following times are missing:
990200042-990200669
990300045-990300492
990400044-990400800
990500032-990500635
990600044-990600725
990700037-990700704
990800032-990800677
990900037-990900719
To summarize, after writing the first two frames in a data directory, the next ~10 minutes of frames are usually missing. To make matters worse (for
the nds2 frame finder, at least) the first frame after the gap (and all successive frames) start at an arbitrary time, usually not aligned to a 16-second boundary. Is there something about the change of directories that is causing the frame builder to crash? Or is the platform/cache disk too slow to complete the directory switch-over without loss of data?
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4771
|
Tue May 31 11:34:13 2011 |
steve | Summary | SAFETY | safety glasses checked |
1064 nm transmison were measured of 40m safety glasses as shown . Their performance did not degrade. They are as good as their labels. |
Attachment 1: P1070823.JPG
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4770
|
Tue May 31 11:26:29 2011 |
josephb | Update | CDS | CDS Maintenance |
1) Checked in the changes I had made to the c1mcp.mdl model just before leaving for Elba.
2) The c1x01 and c1scx kernel modules had stopped running due to an ADC timeout.
According to dmesg on c1iscex, they died at 3426838 seconds after starting (which corresponds to ~39 days). "uptime" indicates c1iscex was up for 46 days, 23 hours. So my guess is about 8 days ago (last Monday or Tuesday), they both died when the ADCs failed to respond quick enough for an unknown reason.
I used the kill scripts (in /opt/rtcds/caltech/c1/scripts/) to kill c1spx, c1scx, and c1x01. I then used the start scripts to start c1x01, then c1scx, and then finally c1spx. They all came up fine.
Status screen is now all green. I renabled damping on ETMX and it seems to be happy. A small kick of the optic shows the approriately damped response. |
4769
|
Mon May 30 23:14:27 2011 |
valera | Update | ASC | Y arm initial alignment |
I closed all 8 dither loops for the Y arm initial alignment: 2x2 centering servo (this worked before) and 2x2 input beam servo for both pitch and yaw.
So far it looks pretty good - the error points go to zero and the arm power goes up to 1.
The offloading to the alignment biases and the PZTs is not yet automated.
Today the PMC, MC, and Y arm were very cooperative and a pleasure to work with. |
4768
|
Fri May 27 17:52:53 2011 |
steve | Update | LSC | LSC rack cables strain relieved & labeled |
LSC rack 1Y2 cables are strain relieved and labeled. Spare and/or obsolete cables are laid out on the top of the beam tube and on the outside of the rack.
The POY 110 MHZ demodboard has a very touchy position in the VME crate. Watch out for it! It has to be fixed. |
4767
|
Thu May 26 17:10:21 2011 |
Jamie | Configuration | LSC | New digital lockin added to LSC model/screen |
Quote: |
A future improvement would be to modify the DCPD input matrix to be able to route those signals to the lockin as well. This is actually currently possible since the DCPD input matrix is just a subset of the full input matrix, but it's not available via medm yet.
|
I went ahead and added the lockin output to the DCPD input matrix.
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4766
|
Wed May 25 20:12:55 2011 |
Jamie | Configuration | LSC | New digital lockin added to LSC model/screen |
Quote: |
This is OK....but, the input matrix should come from the same place as the regular input matrix: i.e. it should be just another row like CARM, DARM, etc. rather than have its own screen.
|
You're absolutely right. That was a brain-fart oversight. I fixed the model so that the input from the lockin comes from another output row in the RFPD input matrix. I then fixed the C1LSC medm screen accordingly:

This is obviously much simpler and more straight-forward.
A future improvement would be to modify the DCPD input matrix to be able to route those signals to the lockin as well. This is actually currently possible since the DCPD input matrix is just a subset of the full input matrix, but it's not available via medm yet. |
4765
|
Wed May 25 19:19:11 2011 |
Jamie | Configuration | CDS | !!!CHECK IN YOUR MODELS!!! |
!!!CHECK IN MODEL CHANGES!!!
Today I found three models that were modified, but not checked in to the SVN repository:
M sus/c1/models/lib/sus_single.mdl
M isc/c1/models/c1lsc.mdl
M isc/c1/models/c1mcp.mdl
I checked in the c1lsc model, since I think it was just the change that Kiwamu made in http://nodus.ligo.caltech.edu:8080/40m/4749. I left the others, since I have no idea what they are or who made them.
Please please please remember to commit your model changes to the SVN after you're done. This is particularly important for important models, such as c1lsc. If you don't check in your changes I can pretty much guarantee that at some point you will loose them.
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4764
|
Wed May 25 19:03:59 2011 |
Jamie | Configuration | CDS | Update rtcds checkout of cds_user_apps with new top-level directory names. |
The top-level subsystem subdirectories in the cds_user_apps source repository were renamed today to be all lower case. This required checking out the new directory and updating all of the model links in /opt/rtcds/caltech/c1. Here is how I updated the cds_user_apps working tree:
cd /opt/rtcds/caltech/c1/userapps
mv trunk{,.bak}
svn update --depth=files trunk
svn update --depth=empty trunk/{cds,isi,isc,psl,sus}
I then fixed the links in the /opt/rtcds/caltech/c1/core/release/src/epics/simLink directory:
for link in $(find . -maxdepth 1 -type l); do ln -sf $(readlink $link | tr [:upper:] [:lower:]) ; done
A couple of things had to be cleaned up:
- /opt/rtcds/caltech/c1/userapps/trunk/cds/c1/models/c1uct.mdl was linked in, but that model doesn't seem to exist anymore, so I removed the link.
- a couple of things were linked from /opt/rtcds/caltech/c1/userapps/trunk instead of /opt/rtcds/caltech/c1/userapps/release, so I fixed those links.
- /opt/rtcds/caltech/c1/userapps/release/cds/test/models/llo/l1isctest.mdl was not checked out, so I checked it out and fixed the link (this model should really be named something different if it is of common use, or we plan on using it at the 40m).
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4763
|
Mon May 23 18:16:42 2011 |
Koji | Configuration | LSC | POY55 installed |
The DC Transimpedance of POP55 was increased from 50 Ohm to 10010 Ohm. There is the offset of 46mV. This should be cancelled in the CDS.
Quote: |
Last Saturday the POY55 RFPD (see this entry) was installed on the ITMY optical bench for the trial of the DRMI locking.
Since the amount of the light coming into the diode is tiny, the DC monitor showed ~ 3 mV even when the PRC was locked to the carrier.
In order to amplify the tiny RF signal from the photo diode a ZHL amplifier was installed next to the RFPD. The RF amp is sitting on delrin posts for insulation from the table.
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4762
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Mon May 23 18:10:41 2011 |
kiwamu | Update | LSC | f2p filters on PRM : not good |
During the DRMI trial I noticed that the f2p filters on PRM is not quite effective (i.e. pushing PRM in POS direction makes misalignments).
I checked the f2p filters in an easy way. I pushed POS at 0.01 Hz with an amplitude of 1000 counts and looked at the oplev error signals with / without the f2p filters.
The picture below is a time series of the POS excitation, the oplev's PITCH and YAW error signals.
You can see there still is a big coupling from POS to YAW after the f2p filters were enabled. (Its supposed to be like this)
I will redo the f2p measurement on PRM.

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4761
|
Mon May 23 14:28:23 2011 |
kiwamu | Configuration | LSC | POY55 installed |
Last Saturday the POY55 RFPD (see this entry) was installed on the ITMY optical bench for the trial of the DRMI locking.
Since the amount of the light coming into the diode is tiny, the DC monitor showed ~ 3 mV even when the PRC was locked to the carrier.
In order to amplify the tiny RF signal from the photo diode a ZHL amplifier was installed next to the RFPD. The RF amp is sitting on delrin posts for insulation from the table.
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4760
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Mon May 23 12:27:26 2011 |
kiwamu | Update | LSC | DRMI trial : details |
(PRMI locking with slightly misaligned SRM)
First I tried locking PRC and MICH with a little bit misaligned SRM. This condition allowed me to search for a good signal port for SRC.
In this locking, REFL11_I was used to lock PRC and AS55_Q was used for MICH. This is the same scheme as the current PRMI locking.
Since the alignment of SRM was close to the good alignment, I expected to see fringes from SRC in some signal ports (i.e. REFL55, POY55 and so on).
Sometimes a fringe of SRC disturbed AS55_Q and broke the MICH locking, so I had to carefully misalign SRM so that the SRC fringes are small enough to maintain the lock of MICH.
(Looking for a good signal port for SRC)
After I locked the PRMI with slightly misaligned SRM, I started looking for a good signal port for SRC.
At the beginning I tried finding a good SRC port by shaking SRM at 100 Hz and looked at the power spectra of all the available LSC signals.
I was expecting to see a 100 Hz peak in the spectra, but this technique didn't work well because SRC wasn't within the linear range and hence didn't produce linear signals.
So I didn't see any strong signals at 100 Hz and finally gave up this technique.
Then I started looking for a PDH-like signal in time series and immediately found AS55_I showed large PDH-like signals.
So I started using the AS55_I for the SRC locking and eventually succeeded.
(Two tips for the DRMI locking)
During the locking of DRMI, I found two tips that made the locking quite smooth.
- Triggered locking
Since every LSC signal ports showed large signals from PRC somehow, feeding back the signals made the suspensions crazy.
So I used triggered locking for the PRC and MICH locking to avoid unwanted kicks on BS and PRM.
If the DC of REFL goes above a certain level, the control of PRC starts. Also if the DC of AS goes below a certain level the control of MICH starts.
These triggers make the lock smoother.
- Do not use resonant gain filters
This is really a stupid tip. When I was trying to lock MICH, the lock became quite difficult for some reasons.
It looked there was an oscillation at 3 Hz every time the MICH control started. It turned out that a 3 Hz resonant gain filter had been making it difficult.
All the resonant gain filters should be off when a lock acquisition is taken place.
Quote from #4759 |
Eventually the DRMI was locked.
More details will be reported in the morning.
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4759
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Mon May 23 00:36:51 2011 |
kiwamu | Update | LSC | DRMI trial : sucess |
Eventually the DRMI was locked.
I was struggling to find a good signal port for SRC over the weekend and finally found AS55_I worked somehow. I used :
REFL11_I --> PRC
AS55_Q --> MICH
AS55_I --> SRC
A configuration script was prepared such that someone can try this configuration by clicking a button on the C1IFO_CONFIGURE.adl screen.
I don't think this signal extraction scheme is the best, but now we can find better signal ports by shaking each DOF and looking at each signal port.
More details will be reported in the morning.
Quote: |
I will try with POY55 that Koji prepared today.
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4758
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Sat May 21 17:02:38 2011 |
Koji | Update | Electronics | Alberto's 11MHz was modified to POP55MHz |
- Resonant at 55MHz. The transimpedance is 258Ohm. That is about half of REFL55 (don't know why).
- 11MHz&110MHz notch
- The 200MHz oscillation of MAX4106 was damped by the same recipe as REFL11.

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Attachment 1: POP55_schematic_110520_KA.pdf
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Attachment 2: POP55_transimpedance.pdf
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4757
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Sat May 21 06:19:46 2011 |
kiwamu | Update | LSC | DRMI trial : no luck |
I will try with POY55 that Koji prepared today. |
4756
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Fri May 20 11:37:44 2011 |
Koji | Update | Electronics | REFL11 fixed (REFL11 not working) |
- Found the inductor which shunts the positive input of MAX4107 was not touching the ground.
This left the positive input level undetermined at DC. This was why MAX had been saturated.
The PCB has a cut, so it was surprising once the circuit worked.
- Resoldered the inductor to the ground. This made the circuit responding to the intensity-modulated beam.
- But the resonances and the notches were totally off, and the 200MHz oscillation has resurrected.
- Attached 40Ohm+22pF network between the neg-input of MAX and the gnd. This solved the oscillation.
- Made the tuning and the characterizations. The PD is on Kiwamu's desk and ready to go.
More to come later
Quote: |
I took REFL11 out from the AS table for a health check because it wasn't working properly.
The symptoms were :
- a big offset of ~ -3 V on the RF output. No RF signals.
- The DC output seemed to be okay. It's been sensitive to light.
I did a quick check and confirmed that +/- 5V were correctly supplied to the op-amps.
It looks that the last stage (MAX4107) is saturated for some reasons. Need more inspections.
At the moment the REFL11 RFPD is on the bench of the Jenne laser.
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Attachment 1: REFL11_transimpedance.pdf
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4755
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Fri May 20 05:41:22 2011 |
Suresh | Update | RF System | Demod board measurements |
The POP110 board which had the large Amplitude and Phase unbalances was examined today. It turned out that there was some stray solder which had connected the Sum port of the PSCQ-2-120 splitter to its body (ground). After I removed that the amplitude unbalance was 0.3dB however the phase was 105deg. The phase reduced to 90 deg only if the power on the splitter is around 19 dBm. So removed the AT1 (10dB attenuator) and the phase unbalance dropped to 91 deg. However this is not a sustainable solution as the ERA-5 max output is about 19.5 dBm.
As this is a side band power monitor (and not a length sensing RFPD), we can make do with a poorer phase. I will therefore replace the AT1 and adjust the residual phase with cable delay lines.
Quote: |
I measured the amplitude and phase imbalances of the demod boards which have been modified. This is just a basic health check. We hope to use the script that Kiwamu is developing for a more accurate test. The script can also use these measurements as a sanity check. POP110 requires some further attention.

The RF distribution box outputs corresponding to the demod board (eg. AS55_LO --> AS55_demod) were used as LO sources. The RF signal was generated with a Marconi and held a kHz away from the LO frequency. The amplitude and phase unbalance were measured with SR785. The RF Power meter was used to check the LO power in each case.
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4754
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Fri May 20 03:29:04 2011 |
kiwamu | Update | CDS | Binary IO box on 1X5 : LEDs off |
[Steve / Kiwamu]
When Steve was working on the strain reliefs on 1X5 he found that some LEDs on the back side of the binary IO boxes were off.
There are 4 binary IO boxes and their power are directly supplied from Sorensens. According to the display of the Sorensens, the power are correctly generated.
Steve and I checked a picture of the boxes taken before he started working and we found it's been like this.
It might be just a problem of the LEDs or the fuses are blown, but anyway it needs an inspection.
Here is a picture of the back side of the boxes. You can see some LEDs are on and some are off.

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4753
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Fri May 20 03:01:17 2011 |
kiwamu | Update | LSC | locking status |
(PRMI locking)
Since REFL11 has gone I tried locking the PRMI with combination of REFL55 and AS55.
Without any pain the lock of PRMI was achieved successfully. AS55 was used to sense MICH and REFL55 was used for PRC.
(scripting)
Additionally I was modifying several scripts which are invoked from C1IFO_CONFIGURE.adl. Some details about the scripts will be uploaded on the wiki later.
An important thing is that now we are able to use the "restore" commands for the Y arm, X arm, Michelson and PRM locking.
The scripts will automatically acquire the lock of each DOF. The image below is just a screen shot of the medm screen where you can call the scripts.

( Still to do)
* PRM actuator response measurement
* PRC noise budget
* MICH-PRC actuator decoupling |
4752
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Fri May 20 01:02:50 2011 |
loose connection hunter | Update | SUS | loose connection on ETMY rack |
The UL signal of the shadow sensor on ETMY went to zero this evening.
This was due to a loose connection on the cross connection board on the 1Y4 rack.
In order to make them tighten, a combination of stand-offs and screws were installed on the connectors. They won't be loose any more.

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4751
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Thu May 19 19:41:17 2011 |
Suresh | Update | RF System | DAQ channel Assignments for RF PDs |
[Kiwamu, Suresh]
In trying to keep the wiring of the LSC rack as neat as possible, we came up with the following channel assignments of the RF PD signals.
PDI = PD Interface, The PD Interface D-type connectors (#1 to #12) are numbered: Top -> Bottom and Left -> Right in ascending order.
The Analog channels on the LSC Whitening Filter boards are numbered similarly, 1 to 32 in four sets.

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4750
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Thu May 19 17:53:03 2011 |
steve | Update | CDS | AA filter box modified at 1X5 |
Quote: |
[Steve, Joe]
Steve pulled the top AA filter box from 1X5 which handled some of the suspensions channels. We turned off all the watchdogs before pulling it out, as well as recorded which cables were connected to which inputs.
The case is undergoing a structural modification to have the ADC adapter card which previously was loosely connected via cables, securely attached to the case.
Steve still wants to do some cabling in the rack while the box is out, and will return it this afternoon once he has finished that.
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Job is done. Sus damping are back on. Cabling-strain reliefing are not finished yet at 1X5 and 1X4 |
Attachment 1: P1070727.JPG
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4749
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Thu May 19 16:46:20 2011 |
kiwamu | Update | LSC | c1lsc model : input channels rearanged |
According to Suresh's LSC rack design I rearranged the input channels of the c1lsc model such that the analog signals and the ADC channels are nicely matched.
Also I updated the c1lsc model in the svn with a help from Joe. The picture below is a screen shot of the input channels in the model file after I edited it.

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4748
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Thu May 19 12:09:41 2011 |
josephb | Update | CDS | AA filter box pulled from 1X5, optic suspensions currently off |
[Steve, Joe]
Steve pulled the top AA filter box from 1X5 which handled some of the suspensions channels. We turned off all the watchdogs before pulling it out, as well as recorded which cables were connected to which inputs.
The case is undergoing a structural modification to have the ADC adapter card which previously was loosely connected via cables, securely attached to the case.
Steve still wants to do some cabling in the rack while the box is out, and will return it this afternoon once he has finished that. |
4747
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Thu May 19 03:13:54 2011 |
kiwamu | Update | Electronics | REFL11 not working |
I took REFL11 out from the AS table for a health check because it wasn't working properly.
The symptoms were :
- a big offset of ~ -3 V on the RF output. No RF signals.
- The DC output seemed to be okay. It's been sensitive to light.
I did a quick check and confirmed that +/- 5V were correctly supplied to the op-amps.
It looks that the last stage (MAX4107) is saturated for some reasons. Need more inspections.
At the moment the REFL11 RFPD is on the bench of the Jenne laser.
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4746
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Thu May 19 00:23:44 2011 |
rana | Update | CDS | diagonalization of MC input matrix |
I've moved all of my SOS peak fitting stuff into the scripts area so that Leo can make it better:
/cvs/cds/rtcds/caltech/c1/scripts/SUS/peakFit
findPeaks.m gets the data and makes the fitted spectra that I put in the previous entry.
findMatrix.m is the barely started script that ought to take the TF data and output the matrix to the MEDM screen. |
4745
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Thu May 19 00:22:21 2011 |
rana | Update | elog | Restarted, Italian-style |
Quote: |
Aka, from a hotel in Pisa.
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Restarted Thu May 19 00:21:49 2011 to recover from Jenne's Italian terrorism. |
4744
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Thu May 19 00:15:20 2011 |
Jenne | Update | elog | Restarted, Italian-style |
Aka, from a hotel in Pisa. |