I did some work on the ETMY real and Sim.
It seems like there is still a problem with the input whitening filters. I believe the Xycom logic is set such that the analog whitening of the OSEM signals is turned ON only when the FM1 is turned OFF. Joe has got to fix this (and elog it) so that we can damp the suspension correctly. For now, the damping of the ETMY and the SETMY require different servo gains and signs, probably because of this.
Using 2 dBm for a Level 7 mixer is so bogus, that I will dismantle this as soon as I come over.
Its going to need some kind of way to locate the PMC on the top. In the previous design, we had the 3 balls to decouple the body from the base. That design was flawed due to the roughness of the holes in the PMC body.
Also probably need some kind of relief on the bottom. Its possible that it would be OK like this, but I am unsure if the shop can maintain the flatness we want over the whole length and/or the flatness of any given (OLD) optical table over ~8". Its probably not a good idea to have to torque this (aluminum?) to make it conform to the optical table's shape.
Ooh. Can you explain the purpose of the resistors which are connected to the (+) inputs? It looks like some real electronics ninjitsu.
I am a little concerned about using these low pass filters so close to the band edge. Recall that there is no on-board preamp for the RF input to the mixer.
So, if the input impedance of the filters is not 50 Ohms, we will get some unwanted reflections and sensitivity to cable length.
I think its worth while to check the impedance or S-parameters of these things with the LO activated to find out if we need to remove them or not.
One way to avoid some of the bad stuff in there is to take the 1 dBm input and amplify it to ~21 dBm before splitting and sending in to the Level 17 mixers.
One way to do this is by using the A3CP6025 from Teledyne-Cougar. Its an SMA connectorized amp which can put out 25 dBm and has a gain of 24 dB. We can just glue it onto the demod boards. Then we can remove the ERA-5 amplifiers and just use the broadband splitter as Kiwamu mentioned.
The performance plots for POX_11 in the wiki are horrendous and the schematic is missing.
I opened up the box and found all kinds of horrors. There were multiple tunable parts and a flurry of excess nonsense.
The top 2 worst offenders:
1) The main tunable inductor was busted. I removed it and found that the coil was open. Too much indelicate soldering in its vicinity had melted the wire. Someone had put extra inductors and capacitors around it to make it seem as if the PD was working fine, but the noise performance was off by a factor of ~100.
2) The MAX4107 had a 1.4k series resistor. This make the output go through a 1450/50 voltage division which is not nice for the SNR. I removed it.
I then struggled for awhile to get a sensible response. It turned out that the TEST IN input was not giving me a sensible TF. Jenne and I fired the Jenne laser at it and found that the 11 MHz main resonance is there. In the morning I'll finish this off and post more results. I think its going to end up being fine.
I used the Jenne AM laser to tune up the PD (used to be POX_11 but now is called REFL_11). In addition to the notch at 22 MHz, I have also put in a LC notch at 5*f = 55.3 MHz. The transfer function below shows the RF OUT of the PD v. the drive to the laser. I didn't divide out by the 1811 because its not on the EE bench.
I worked on AS_11 today. Its ready for its noise / optical gain calibrations. I have left it on Suresh's desk.
This was one of the 24.5 MHz Black Box (Ben Abbott) style RFPDs rescued from LLO. The tunable inductor that was installed was too small to get the frequency down to 11 MHz and so I swapped in one of the shielded, ferrite core ones from our '7mm' CoilCraft kit. It had a range of 1.2 - 1.8 uH according to the datasheet.
I wasn't able to simulataneously get the peak at 11.06 MHz and the notch at 59.3 MHz and so I took Koji's advice and tuned the peak best. The plot above shows how the notch is slightly off. I think its not a problem; to get it better we would have to change out the inductor for the "2-omega" notch, but I was too lazy. The thinking is that its more important to have the gain be symmetric around the signal readout frequency so as to not imbalance the audio sidebands.
Since this one is going to be AS_11, we think that the 22 MHz signal will be tiny: the transmission of the 11 MHz sidebands to the dark port is small. If we later want to put in a 22 MHz notch anyway, there is space to do this via the 'active notch' pads around the MAX4107.
For the above plot, I used the Jenne laser. The DC output of the PD was ~30 mV (~0.6 mA). The RF drive to the laser was -10 dBm: no saturations. I have calibrated out the cable responses, but not using the 1811 setup, so the absolute calibration has yet to be done.
Also, it needs some new stickers. It would be handy if someone can figure out how to get some sheets of stickers that we can put into the printer. Then we can laser printer all of the data onto the stickers and stick them to the RFPD box.
* Farfalla, a lab laptop, seems out of network.
If you look at the real host table instead of the misleading host table in the wiki, you will see that someone has deleted Farfalla from there. She needs to be re-added.
I found that the MC autolocker was OFF. Kiwamu says he turned it off because its slow. Suresh says that he has some feelings that maybe something is wrong. I'll let them describe what they know about the MC in an elog.
I checked the trend of the MC and PMC transmissions for the past 30 days:
Looks like the alignment has been drifitng. PMC was corrected recently by Koji, but the alignment of the input beam to the MC or the MC itself has to be fixed. Has someone been twiddling the MC SUS alignment biases??
I think that the gain ramping time (_TRAMP) should be set to 1 second for all filter modules by default. We don't want them to switch instantaneously except in a few special cases.
So Jamie and I wrote a script (in scripts/general/) which sets all of these fields to 1 for a given system. The name of the system is an argument to the script. e.g.
> setTRAMP LSC 1
The idea is that we set it once and then from then on, its captured by the autoBURT. Of course, we have to run this script each time we add new filter modules to a model.
It seems like the best option would be to make the MCASS just adjust the SUS biases and center the beams on the suspended optics. Is this not possible somehow?
I looked at the PSL temperature box. It started out as D980400-B-C. Then it was revised by Peter King as per the LHO mods E020247.
There are some more things to do to it to make it useful for us:
** Frank reminds me that we don't use the TIdal or VME external inputs anymore since we moved to the EPICS/Perl PID control. So all we have to do is make sure these inputs are hardware disabled/disconnected.
I re-installed the box (@ ~8:15) after reflowing some of the solder joints. I will observe it over night and then remove the 1K resistors. Attached is a 8 hour minute-trend.
I compared this 24 hour trend with the one from this day exactly one year ago. Seems the same, so now I can make the resistor change.
I found that a He-Ne laser which has been used for ETMX_OPLEV was NOT giving the light.
Since I didn't find the switch key for it I have no idea if the laser is simply off or dead.
The dead laser was replaced by new JDSU 1104P of 2.6mW. The return beam is big ~5 mm diameter of 0.3 mW, 1400 counts
Whenever replacing any Oplev laser, please also put into the ELOG when it was installed so that we have an electronic record of the laser lifetime.
Rana also advised that we must use the boards which have the piggy-back amplifiers on those signals which are most useful. We referred to Alberto's thesis and chose POY55 (MICH and SRCL), REFL11(PRCL) and AS55 (DARM) as the most useful signals. We currently have these amps on AS11, REFL11 and AS55. We need to convert either AS11 or REFL11 into a POY55. Since we need to troubleshoot REFL11, I thought we might as well modify that and in the process also fix its Q output. So I renamed AS11 as REFL11 and will convert the old REFL11 into POY55 tomorrow.
I think we should leave them as is; the AS11 was made by taking into account the SB levels at the AS port and should not become REFL11. We should instead convert one of the old 25 or 33 MHz diodes into a POY55.
We decided to rename the Input Beam channels (while keeping temporary backwards compatible aliases) as:
C1:ASC-IB_POS_X, C1:ASC-IB_POS_Y, C1:ASC-IB_ANG_SUM, etc.
Looks like 2 different MEDM Snapshot functiions (at least) are broken.
The regular update of the screens here as well as the usual "Update Snapshot" and view "previous snapshot" button on all of the auto-generated screens.
Also, how do we add the snapshot button to the custom made screens?
There has been some input matrix diagonalization in the past by Yuta and Kiwamu, but I find the automation to be not totally satisfactory.
It would be better if we could automatically fit the data to find the Suspended optic eigenfrequencies and then use that to get the matrix. So I wrote a peak fitter to get the matrix.
It gets the data from mafalda with NDS2, then it makes the PSDs, and then starts with some initial guesses (based on looking at the plots) and them uses fminsearch to get the peak frequencies and Q's.
Using the output of this, we can use Yuta's method and take the passive transfer functions with the free swing data (from April 30, so we got do do it quick) to get the input matrix.
Doing the SUS input matrix is nice for having good damping (as long as we remember to include SIDE), but my motivation is to produce a good null stream from the 4 face sensors so that we can estimate the sensor noises at all times.
Just FYI, the 3113 is a 12-bit ADC, so we won't get very good resolution out of these. We should get one of those purple boxes.
Also, I corresponded some with Dave Barker. The 40m Wiki at LHO is down because of disk errors. He's working on it and will let us know. But suggests that we move it to Caltech since he'll turn the box off at the end of the year.
Mon May 16 13:57:49 2011 Wiki is back up.
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.
Also, I think a nice mod to all the matrices would be if the ORANGE triangle was only visible when there's a signal flowing through it.
Aka, from a hotel in Pisa.
Restarted Thu May 19 00:21:49 2011 to recover from Jenne's Italian terrorism.
I've moved all of my SOS peak fitting stuff into the scripts area so that Leo can make it better:
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.
I've finished tuning POY11 and it is now sitting on top of the analyzer waiting for Koji to test its noise.
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...
I focused these lenses so that we could get a clean image of the mirrors and the OSEMs.
Our goal is to have an image where the optic diameter almost fills the entire monitor. We want the focus to be adjusted for the YAG beam (which is almost the same as focusing for the OSEMs). This will NOT produce a nice image of the cage using visible light, but that is just fine.
When Justin Garofoli was here he found a nice lens combo that did the job, so if anyone can find his old email or elog, lets just go back to that.
For now, we do not need a camera/lens system to focus very tightly on the center of the optic.
While answering a quick question by Kiwamu, I noticed we only had second trends going back to 99050000 GPS time, May 27th 2011.
Trends (I thought) were intended to be kept forever, and certainly longer than full data, which currently goes back several months.
Jamie will need to look into this.
Our concept is to keep second trends for 1-2 months and minute trends forever. The scheme that Alan had worked out many years ago had it such that we could look back to 1998 and that the minute trends would be backed up somehow.
If its not working, we need to get Alan's help to recover the previous configuration.
Koji and I found 2 RFPD boxes to send to LLO. We've put them onto Steve's desk to be overnighted to Valera.
One of them is our old 21.5 MHz gold box RFPD from the FSS (which we don't use). The other one is a 2mm gold box one which was previously tuned for 66 MHz.
They shipped out on Friday
There was a rogue, undocumented, gateway process running on NODUS since ~4 PM. This guy was broadcasting channels back into the Martian and causing lockups in the IOO controls. I did a kill -9 on its process.
Someone will pay for this.
I put a paper Peet's bag with half of the Mini-Moos into George.
All the suspensions are bad until you fix them. But, ... there is a script which can be used to diagnose them today:
When I try to get minute trend, it says "word too long".
I have updated the scripts/SUS/peakFit/ directory so that it now finds the SUS input matrix coefficients in addition to just finding the free-swinging peaks.
The attached PDF shows how much rejection of the unwanted DOFs we get between the existing diagonal input matrix and this new empirical matrix. Previously, the decoupling was only a factor of a few for some of the modes. Now the decoupling is more like orders of magnitude (at least according to this calculation). It will be worse when we load it and then try another free swinging run. However, the fact that the suppression can be this good means that the variation in the coefficients at the ~hours time scale is at least this small (~< 0.1%)
That's the basic procedure, but there are a lot of important but mainly technical details:
I'll set the optics to be aligned and then swing tonight.
I used scripts/SUS/freeswing-all.csh to give the optics a kick and then turn off their watchdogs and collect the free swinging data. Final script end time = 993173551. Start taking data ~ 993173751
I had to fix up the script a little: it had amateur stuff in there, such as undefined variables.
It still doesn't work that well. On the new Ubuntu workstations, pianosa, it fails by just not setting some of the EPICS variables using the EZCA stuff.
On Allegra, it failed on ~1 out of 10 commands by returning "epicsThreadOnce0sd epicsMutexLock failed" ???
On Pianosa, it sometimes says, instead, "epicsThreadOnceOsd: pthread_mutex_lock returned Invalid argument.". Ah...now I understand?
epicsThreadOnceOsd: pthread_mutex_lock returned Invalid argument.
So finally, I had to run the script on op340m to get it to actually run all of its commands. That's right; I used a 15 year old Solaris 9 Blade 150 because none of our fancy new Linux machines could do the job reliably.
Fixing our EZCA situation is a pretty high priority; if the locking scripts fail to run ~1 command every hour its going to completely derail the lock acquisition attempts.
If you want to use the IFO tonight, just run the script again on op340m again when you're done.
Since the MC1 LRSEN channel is not wasn't working, my input matrix diagonalization hasn't worked today wasn't working. So I decided to fix it somehow.
I went to the rack and traced the signal: first at the LEMO monitor on the whitening card, secondly at the 4-pin LEMO cable which goes into the AA chassis.
The signal existed at the input to the AA chassis but not in the screen. So I pressed the jumper wire (used to be AA filter) down for the channel corresponding to the MC1 LRSEN channel.
It now has come back and looks like the other sensors. As you can see from this plot and Joe's entry from a couple weeks ago, this channel has been dead since May 17th.
993190663 = free swinging ringdown restarted again
The slow readback of the ETMX side seems to also have something flaky and bi-stable. This is not an issue for damping, but it disables the SIDE watchdog for ETMX and makes it unsafe if we accidentally use the wrong damping sign.
Chris Wipf tells me that the EPICS Mutex Jumbo Mumbo can be overcome by upgrading our EPICS. We should get one of Jamie's assistants to get this going on one of the Ubuntu workstations.
Today I wanted to investigate the MC Length path situation for obscure reasons.
Jamie has started to revert the "ALTPOS" effect on the MC mirrors. So far, the screens and SLOW channels have been fixed, but the fast channels still say "ALTPOS" in the dataviewer instead of "MCL".
I also noticed that all of our old ADCU channels for diagnosing the PSL, MC, ISS, PMC ,etc. are completely AWOL. Let's blame Joe.
I think that there are probably some ADC channels available and that we'll just have to figure out what Joe intended for this. We certainly need it if we want to diagnose our PMC, ISS, FSS, MC, etc. Kiwamu tells us that the old PSL/IOO AA chassis is being used for some of the GCV signals, so its likely that we just have to do the appropriate channel name mapping in the DAQCONFIG tool.
Forging ahead with no data, I made up some filters in the MC2-MCL filter bank so that there could be a stable crossover between the laser path. I was able to turn it on and get some suppression of the FSS-FAST control signal, but there's no way to be sure without the fast channels. We gotta get Jamie to help us out once he finished the ETM BO mess.
As I recently had trouble getting all of the SUS SENSOR channels at once from NDS2, I asked J.Z. for help. He found that the number of buffers on mafalda was set to only allow a small amount of data to be requested at one time.
He's going to have to figure out a more permanent fix, but for now he's increased the data buffer size to allow somewhat larger chunks to be gotten. I have made a work around in matlab, which gets smaller chunks and then cats them together.
Its in SUS/peakFit/.
What is implicit in Suresh's entry is that we decided to run the WFS with the 10 dB internal attenuation set to ON as the nominal. In the past, we have always had all the attenuation OFF for max gain. The layout of the WFS is such that we get that nasty 200 MHz oscillation due to crosstalk between the 2 MAX4106 opamps for each quadrant. The 10 dB attenuator is able to reduce the positive feedback enough to damp the oscillation.
In principle, this is still OK noise-wise. I think the thermal noise of the resonant circuit should be ~2-3 nV/rHz. Then the first opamp has a gain of 5, then the -10 dB attenuator, then another gain of 5. The noise going to the demod board is then ~10-15 nV.
The real noise issue will be the input noise of the demod board. As you may recall, the output of the AD831 mixer goes to a AD797. The AD797 is a poor choice for this application. It has low noise only at high frequencies. At 10 Hz, it has an input voltage noise of 10 nV/rHz and a current noise of 20 pA/rHz. If we wanted to use the AD797 here, at least the RC filter's resistor should be reduced to ~500 Ohms. Much better is to use an OP27 and then choose the R so as to optimize the noise.
We should also be careful to keep the filter frequency low enough so as not to rate limit the OP27. From the schematic, you can see that this circuit is also missing the 50 Ohm termination on the output. There ought to be the usual high-order LC low pass at the mixer output. The simple RC is just not good enough for this application.
As a quick fix, I recommend that when we next want to up the WFS SNR, we just replace the RC with an RLC (R = 500 Ohms, L = 22 uH, C = 1 uF).
Actually, ETMY was the only good one. They should all have the 30 Hz High pass as the damping filter. I think these details are in the elog entry that we originally made while doing ETMY.
They should all also have a 3:30 in the XXSEN to compensate the whitening. The logic is supposed to be that FM1 is ON when the hardware whitening is ON. This is the opposite of the old logic and its why the damping filter has to be moved from 3 to 30 Hz.
MC1 MC2 MC3 ETMX ETMY ITMX ITMY PRM SRM BS mean std
Pitch 0.671 0.747 0.762 0.909 0.859 0.513 0.601 0.610 0.566 0.747 0.698 0.129
Yaw 0.807 0.819 0.846 0.828 0.894 0.832 0.856 0.832 0.808 0.792 0.831 0.029
Pos 0.968 0.970 0.980 1.038 0.983 0.967 0.988 0.999 0.962 0.958 0.981 0.024
Side 0.995 0.993 0.971 0.951 1.016 0.986 1.004 0.993 0.973 0.995 0.988 0.019
There is a large amount of variation in the frequencies, even though the suspensions are nominally all the same. I leave it to the suspension makers to ponder and explain.
This CSHRC mangling on Feb 4 did more than re-arrange FB binaries.
It broke the path to MEDM for the 32-bit machines in the lab (e.g. mafalda) and stopped the MEDM snapshots from being posted onto our MEDM Status Web Page.
This is because, in addition to the paths mentioned in the above elog, the paths to the EPICS directories were also commented out. I've re-inserted them into our
.cshrc file in the 32-bit section; the statScreen CRON that Yoichi set up is now back in business.
* for some reason, the 'cronjob.sh' script is wiping out its own log file. It would be great if someone who understands stderr output re-direction can fix it so that the log-file from each run is retained until the next time cron runs.
This is getting closer, but with the whitening left OFF and the cts2um filter also OFF, none of the suspensions are working correctly. I'm shutting down all the watchdogs until someone gets around to setting the damping gains and filters correctly.
I'm attaching a screenshot of some of the problems I see so far with MC3.
I'm going to try to get the MC suspensions working OK for tonight so that we can use them for the PRMI locking work.
Update #1: None of the MC SUS DAQ channels are found by dataviewer....SUS debugging speed reduced by 10x. Tue Jul 05 21:38:17 2011
Update #2: POS/PIT/YAW BIAS sliders now seem to work, but are ~1000x too weak to do anything. Tue Jul 05 21:41:38 2011
In addition to the OL quadrants, you need to plot the OPLEV_PERROR and OPLEV_YERROR signals since these are the real signals we use for finding the mirror motion. If they're not in the Dataviewer, Jamie should add them as 256 Hz DAQ channels (using these names so that we have the continuity with the past). These DAQ channels correspond to the IN1 channels for the OL filter banks.
Also JPG are banned from the elog - you should put all of the plots into a single, multipage PDF file in honor of the new Wagonga.
At 0 dB, the resistor noise is only 30 nV/rHz, whereas the ADC noise is more like 10000 nV/rHz...
I installed Virtual Box on rossa. Then I put Windows 7 in there and am now installing Altium.
You can run Windows on rossa by just clicking Applications -> System Tools -> Virtual Box.