Work Completed :
- Transfer Function
- Quantization Noise Estimation
EPICS and Channel Readout:
Frequency Offset Locking(FOL) Box Design and Plan:
Work Plan for Upcoming Weeks:
See Attachment #1.
The beam spot on ETMY looks weird (looks almost like a TEM10 mode), but the one on ITMY seems fine, see Attachment #2. Wonder what's going on there, maybe just a focusing problem?
We need a vent to fix the suspension, but until then what we can do is to redistribute the POS/PIT/YAW actuations to the three coils.
The variable delay line has been setup for practical use. The hardware and basic software are ready.
The delay time is given by [512-1-mod(C1:LSC-BO_1_0_SET, 512)]*(1/16) ns
Giving 511 (LLLL LLLH HHHH HHHH) to C1:LSC-BO_1_0_SET makes the delayline shortest (+0ns).
Giving 0 (LLLL LLLL LLLL LLLL) to C1:LSC-BO_1_0_SET makes the delayline longest (~32ns).
The SR785 was removed from the rack for our access >> Eric
- Three CONTEC DO-32L-PE cards are found in the Yarm digital cabinet. (I brought a card from WB, but will bring it back).
- The card was installed in the C1LSC chassis.
- The models for c1x04 and c1lsc were modified to include the card. Once they are restarted, the card was recognized without problem.
The frame builder also needed to be restarted (Attachment 1&2). The changes were committed to the repository.
- MEDM screen "CDS_BO_STATUS.adl" has been modified to include the bit monitors for the new DO card. (Attachment 3)
Epics values "C1:LSC-BO_1_0_SET" and "C1:LSC-BO_1_1_SET" are hooked up to the DO block.
- The DO board has DB37(F). I made a I/F cable with a DB37(M) crimp connector, DB25 breakout board, and a ribbon cable.
Pin 1 is connected to pin 14 of the DB25 (GND of the delayline circuit).
Pin 2~10 are connected to pin 1~9 of the DB25 (Switch 1~9 of the delayline circuit)
Pin 18 is connected to X01 (external = spare) (Attachment 4)
- [CONFESSION] A bench +15V power supply was prepared to power the transisters of the DO (Attachment 6). The hot side is connected to X01 (not connected to the DB25),
and the cold side is connected to pin 14 of the DB25. Once we find this is a useful setup we need to make a dedicated interface unit to convert DB37
into DB25 (and provide more connectivities).
- A DB25 M-F cable was installed on the cable tray above the LSC racks.
Delay line unit
- The delay line box was mounted on 34H of the LSC analog rack (Attachment 5).
- The side cross connect power supply was not available (to be described later). Therefore we decided to use the same +15V supply as the one for the DO card.
- Checked the functionarity of the local switches using a function generator @30MHz and the front panel switches. The maximum (~32ns) delay was confirmed.
(Just not enough to have 360 deg shift).
- Now the delay line function was tested with the front panel swicth at "ext". We confirmed that the delay time changes with the number given to C1:LSC-BO_1_0_SET.
What we need further
- Implement delay time slider control (511 = 0ns, 0 = 31.94ns). The delay time is given by
[512-1-mod(C1:LSC-BO_1_0_SET, 512)]*(1/16) ns
- Some independent RF issues I found. (Next entry)
All the details are in E2000436, and documents linked from there, I think an elog would be much too verbose. In summary, a workable setup consisting of
Last night, I locked the PRMI with the carrier resonant, and convinced myself that the DCPD null stream was sensing the MICH degree of freedom (while it was locked on AS55_Q) with good SNR below ~60 Hz. Above ~60 Hz, in this configuration, the ADC noise was dominating, but by next week, I'll have a whitening board installed that will solve this particular issue. With the optical gain of MICH in this configuration, the ADC noise level was equivalent to ~500 nrad/rtHz of phase noise above ~60 Hz (plots later).
Now, I can think about how to commission this setup interferometrically.
[josephb, osamu, kiwamu]
We worked over by the 1Y2 rack today, trying to debug why we didn't get any signal to the c1lsc ADC.
We turned off the power to the rack several times while examining cards, including the whitening filter board, AA board, and the REFL 33 demod board. I will note, I incorrectly turned off power in the 1Y1 rack briefly.
We noticed a small wire on the whitening filter board on the channel 5 path. Rana suggested this was to part of a fix for the channels 4 and 5 having too much cross talk. A trace was cut and this jumper added to fix that particular problem.
We confirmed would could pass signals through each individual channel on the AA and whitening filter boards. When we put them back in, we did noticed a large offset when the inputs were not terminated. After terminating all inputs, values at the ADC were reasonable, measuring on from 0 to about -20 counts. We applied a 1 Hz, 0.1 Vpp signal and confirmed we saw the digital controls respond back with the correct sine wave.
We examined the REFL 33 demod board and confirmed it would work for demodulating 11 MHZ, although without tuning, the I and Q phases will not be exactly 90 degrees apart.
The REFL 33 I and Q outputs have been connected to the whitening board's 1 and 2 inputs, respectively. Once Kiwamu adds approriate LO and PD signals to the REFL 33 demod board he should be able to see the resulting I and Q signals digitally on the PD1 I and Q channels.
In an unrelated fix, we examined the suspensions screens, specifically the Dewhitening lights. Turns out the lights were still looking at SW2 bit 7 instead of SW2 bit 5. The actual front end models were using the correct bit (21 which corresponds to the 9th filter bank), so this was purely a display issue. Tomorrow I'll take a look at the binary outputs and see why the analog filters aren't actually changing.
After hardware errors prevented me from using optimus, I switched my generation of summary pages back to the clusters. A day's worth of data is still too much to process using one computer, but I have successfully made summary pages for a timescales of a couple of hours on this site: https://ldas-jobs.ligo.caltech.edu/~praful.vasireddy/
Currently, I'm working on learning the current plot-generation code so that it can eventually be modified to include an interactive component (e.g., hovering over a point on a timeseries would display the GPS time). Also, the 40m summary pages have been down for the past 3 weeks but should be up and working soon as the clusters are now alive.
Ok, after a few minutes of talking to Alex, I got the correct "GUI syntax" through my head, and we now have a simple working green end control which in fact puts signals out through the DAC.
Note to self, do not put any additional filters or controls in the IOP module. Basically just change the master block with GDS numbers, DCU_ID numbers, etc. When using a control model, copy the approriate ADC and ADC selector or DAC to the control model. It will magically be connected to the IOP.
A correct example of a simple control model is attached.
Next in line is to get the adapter boxes for SUS into the new 1X5 rack and get started on SUS filter conversion and figuring out which ADC/DAC channels correspond to which inputs.
TL;DR: I am now able to inject a swept sine and measure a transfer function with python on my Red Pitaya! Attached is a Bode plot for a swept sine from 1 - 30 MHz, going through a band pass filter of 9.5 - 11.5 MHz.
Steve and Koji
- We removed old ITMX/Y from the chambers. Now they are temporarily placed on the flow table at the end. Steve is looking for nice storages for the 5inch optics.
- We wiped new ITMX/Y by isopropanol as they were dusty.
- We put them into the corresponding towers. Checked the balancing and magnet arrangements with the OSEMs. They were totally fine.
- We clamped the mirrors by the EQ stops. Wrapped the towers by Al foils.
Tomorrow we will put them into the chambers.
I'm currently working on a set of scripts which will be able to parse a "template" mdl file, replacing certain key words, with other key words, and save it to a new .mdl file.
For example you pass it the "template" file of scx.mdl file (suspension controller ETMX), and the keyword ETMX, followed by an output list of scy.mdl ETMY, bs.mdl BS, itmx.mdl ITMX, itmy.mdl ITMY, prm.mdl PRM, srm.mdl SRM. It produces these new files, with the keyword replaced, and a few other minor tweaks to get the new file to work (gds_node, specific_cpu, etc). You can then do a couple of copy paste actions to produce a combined sus.mdl file with all the BS, ITM, PRM, SRM controls (there might be a way to handle this better so it automatically merges into a single file, but I'd have to do something fancy with the positioning of the modules - something to look into).
I also have plans for a script which gets passed a mdl file, and updates the C1.ipc file, by adding any new channels and incrementing the ipcNum appropriately. So when you make a change you want to propagate to all the suspensions, you run the two scripts, and have an already up to date copy of memory locations - no additional typing required.
Similar scripts could be written for the DAQ screens as well, so as to have all the suspension screens look the same after changing one set.
I've opened the AP table and I'm working on it.
I re-aligned the Faraday on the AP table. I also aligned the beam to the periscope on the PSL and all the other optics along the beam path. Now I have a nice NPRO beam at the PLL which overlaps with the PSL beam. The alignment has to be further improved because I see no beat yet.
I wonder if the all the tinkering on the PSL laser done recently to revive the power has changed the PSL NPRO temperature and so its frequency. That could also explain why the beat doesn't show up at the same temperature of the NPRO as I used to operate it. Although I scanned the NPRO temperature +/- 2 deg and didn't see the beat. So maybe the misalignment is the casue.
Not feeling very well right now. I need to go home for a while.
AP table closed at the moment.
NPRO shutter closed
I re-aligned the Faraday on the AP table. I also aligned the beam to the periscope on the PSL and all the other optics along the beam path. Now I have a nice NPRO beam at the PLL which overlaps with the PSL beam. The alignment has to be further improved becasue I see no beat yet.
I wonder if the all the tinkering on the PSL laser done recently to revive the power have changed the PSL NPRO temperature and so its frequency. That could also explain why the beat doesn't show up at the same temperature of the NPRO as I used to operate it. Although I scanned the NPRO temperature +/- 2 deg and didn't see the beat. So maybe the misalignment is the casue.
We definitely changed the PSL NPRO temp while fiddling around, trying to increase the laser power. I think it's noted in the elog both times that it's happened in the last few months (once when Rana, Koji and I worked on it, and then again when it was just Koji), but we opened up the side of the MOPA box so that we could get at (and change) the potentiometer which adjusts the NPRO temp. So you may have to search around for a while.
Yes it did.
For long time, the crystal temperature C1:PSL-126MOPA_LTMP was 43~46deg. Now it is 34deg. Try ~10deg lower temperature.
I wonder if the all the tinkering on the PSL laser done recently to revive the power have changed the PSL NPRO temperature and so its frequency. That could also explain why the beat doesn't show up at the same temperature of the NPRO as I used to operate it. Although I scanned the NPRO temperature +/- 2 deg and didn't see the beat.
Also auxiliary NPRO turned on and mechanical shutter opened.
Beat found at 30MHz with auxiliary NPRO temperature of 37.19 degrees, vs. ~48 deg as it used to be.
The beat is small (-70dBm). PLL alignment has to be improved.
PLL alignment improved. Beat amplitude = -10dBm. Good enough.
DC readouts at the PLL photodiode:
V_NPRO = -4.44V
V_PSL = -3.76V
The NPRO beam is attenuated by a N.D.=1 attenuator just before going to the photodiode.
Something strange happened at the last. Right before -10dBm, the amplitude of the beat was about -33dBm. Then I was checking the two interfering beams with the IR card and saw that they overlapped quite well. I then turned my head back to the spectrum analyzer and suddenly the beat was at -10dBm. Not only, but a bunch of new peaks had appeared on the spectrum. Either I inadvertently hit the PD moving it to a better position or something else happened.
Like if someone was making some other modulation on the beam or the modulation depth of the PSL's sidebands had gone up.
I'm working on the AP table. I also opened the auxiliary NPRO shutter. The auxiliary beam is on its path on the AP table and PSL table.
NPRO shutter closed
I opened the auxiliary laser's shutter.
I'm currently working on the AP table.
I finished working on the table.
I closed the AUX NPRO's shutter.
We are currently using the SUS wiring diagram found on Ben Abbott's page (link here) to determine the ADC/DAC/BO channel numbers for each individual optics inputs and outputs. Basically it involves tracking the paths back from the Pentek's, XY220, and IC110Bs to a point where we can identify it as a Coil UL or a PD whitening filter control or whatever it might be.
Once done we will have a nice wiki page describing what the final wiring is going to be, along with which ADC effectively plugs into which analog board and so forth.
The mode cleaner FF static filtering is by no means done. More work has to be done in order to succefuly implement it, by the means of fine tuning the IIR fit and finding better MISO Wiener filters.
I have begun to look at implementing FF to the YARM cavity for several reasons.
1) Even if the mode cleaner FF is set up as best as we can, there will still be seismic noise coupling into the arm cavities.
2) YARM is in the way of the beam path. When locking the IFO, one locks YARM first, then XARM. This means that it makes sense to look at YARM FF first rather than XARM.
3) XARM FF can't be done now since GUR2 is sketchy.
I'm planning on using this eLOG entry to document my Journey and Adventures (Chapter 2: YARM) to the OPTIMAL land of zero-seismic-noise (ZSN) at the 40m telescope.
donatella was one of our last workstations running ubuntu12. we installed SL7 on there today
Then there are ~20 errors related to gds-crtools that look like this:Error: Package: gds-crtools-2.18.12-1.el7.x86_64 (lscsoft-production) Requires: libMatrix.so.6.14()(64bit)
Batteries + power cables replaced, and computers back on UPS from today ~3pm.
The UPS is now incessantly beeping. I cannot handle this constant sound so I shut down all the control room workstations and moved the power strip hosting the 4 CPUs to a wall socket for tonight. Chub and I will replace the UPS batteries tomorrow.
We got a new computer from Xi computer corp. I am currently installing Ubuntu 10.04 LTS on to it to start with and then will move on to 12 if we can figure out a way to test it besides "I guess it should work?"
Rosalba has been removed and put onto the old Jamie desk. Old Jamie desk also has a Mac Mini running on there.
At the meeting tomorrow we need to decide on a new Italian baby girl name for this new machine.
I've finished setting up the fstab on Chiara and the upgrade to Ubuntu 12 seems to have gone well enough. She's fast:
but I forgot to make sure to order a dual head graphics card for it. So we'll order some dual DVI gaming card that the company recommends. Until then, its only one monitor.
Still, its ready for testing control room tools on. If everything works OK for a couple weeks, we can go to 12 on all the other ones.
1)The PDFR scripts have all been migrated into /scripts/PDFR/
2) The MEDM screen to run PDFR is /medm/MISC/PDFR.adl
3) A new button has been added on sitemap to open the above medm window.
4) All data and plots generated will sit in /scripts/PDFR/"PD Name"/
5) All features are working after the migration and absolute file paths are being used.
Work Remaining : Manual for others to make changes and keep using my system.
We dither locked the X arm and then aligned the green beam to it using the PZTs. Everything looks ready for us to do a mode scan tomorrow.
We got buildup for Red and Green, but saw no beat in the control room. Quick glance at the PSL seems OK, but needs more investigation. We did not try moving around the X-NPRO temperature.
Tomorrow: get the beat, scan the PhaseTracker, and get data using pyNDS.
Den and I spent some time with the interferometer last night with hopes of bringing in the AO path, but were stymied by the (re)occurrence of the anomalously high low frequency motion of the Xarm, as seen by fluctuations of TRX from .9 to .2 while "held" on resonance.
Jenne reported that they weren't seeing it earlier in the evening, and then it started again when I showed up. Holding the arms on IR, we could see a fair amount of excess low frequency noise in the BEATX_FINE_PHASE_OUT_HZ channel, as compared to BEATY, bringing its RMS to 5 times that of the Y arm. From the shape of the excess noise (broad slope from DC to tens of Hz), Rana suspected air currents and/or scattering effects being the culprit.
Den poked around a bit on the PSL table, which didn't really change much. He then went down to the X end table to inspect the table, and while he was there, I noticed the noise go down to being in line with the Yarm. I joined him at the end, and we found the beat phase noise in the frequency region of concern to be hugely sensitive to tapping on the enclosure, air current, etc. There is also a ton of green light everywhere, and multiple spots of green light around the green refl PD.
At that point however, the quiescent noise was acceptable (TRX fluctuations of <.2), so we went back to the control room to try to lock. Unfortunately, after a few attempts, the noise was back. At this point, we went home. The layout of the end table likely needs some attention to try and minimize our susceptibility to excess scatter effects.
Turn off the AC and flow bench please.
Leaving LSC mode OFF for now while CDS is still under investigation
Not really related to this work: We saw that the safe.snap file for c1oaf seems to have gotten overwritten at some point. I restored the EPICS values from a known good time, and over-wrote the safe.snap file.
My motivation tonight was to get an up-to-date spectrum of a calibrated measurement of the out-of-loop displacement of an arm locked on ALS (using the PDH signal as the out-of-loop sensor) to compare the performance of ALS control noise with the Izumi et al green locking paper.
I was able to fish out the PSD from the paper from the 40m svn, but the comparison as plotted looks kind of fishy. I don't see why the noise from 10-60Hz should be so different/worse. We updated the POX counts to meters conversion by looking at the Hz-calibrated ALSX signal and a ~800Hz line injected on ETMX.
It seems that just repeating the measurement was enough to get a good transfer function of the x arm cavity. Here's what I got.
I'm going to fit the data on matlab, but at first sight, the pole seems to be at about 1.7KHz (that is where the phase is 45deg): as expected.
Probably it was useful to realign the beam on the Transmission PD. (btw, I'm using the PDA255 that was still on the X end table since the AbsL experiemtn that measured the arm length)
I measured the transfer function between MC_TRANS and TRX and I'm attaching the result.
That looks quite strange. Something's wrong. I'll repeat it tomorrow.
for the night I'm putting everything back. I'm also reconnecting the OMC_ISS_EXC and opening again the test switch on the ISS screen.
The RFAM monitor remains disable
I would have guessed that you have to calibrate the detectors relative to each other before trying this. Its also going to be tricky if you use 2 different kinds of ADC for this (c.f. today's delay discussion in the group meeting).
I think Osamu used to look at fast transmission signals by making sure the PD at the end had a 50 Ohm output impedance and just drive the 40m long cable and terminate the receiving end with 50 Ohms. Then both PDs go into the SR785.
On Rana's suggestion I measured the trasfer function between the two photodiodes PDA255 that I'm using.
I took the one that I had on the end table and put it on the PSL table. I split the MC transmitted beam with a 50% beam splitter and sent the beams on the two diodes. (Rana's idea of picking off the beam and interposing the PDs before the ISS PDs was not doable: ISS PDs would be too close and there would be no room to install the PDA255 before them). See picture with the final setup.
The transfer function also includes the 40m long cable that I was using for the Arm Cavity measurement.
Here's what I got. It looks rather flat. Yesterday the calibration was probably not the problem in that measurement.
I'm now going to install the PD back on the end table and measure the TFs between the excitation and several points of the loop.
(Trivia. At first, the PDs were saturating so Koji attached attenuation filters on to them. Suddenly the measurement got much nicer)
Rana suspects that the lack of X beatnote is related to the PSL laser temperature change (ELOG 11294).
I used the information on the wiki and old elogs (wiki-40m, ELOG 6732), to deduce that the new end laser temperatures should be:
I went out to the X end and found the laser crystal temperature set to 40.87, which is not what the measurements I linked to suggest would be the ideal temperature for the previous NPRO laser temperature of 30.89, which would be 37.02. I could not find any elog describing the choice of this setpoint.
I've changed the X end laser crystal temperature to the value above. I've hooked up the X IR and green beatnotes to go the control room analzyer, and have been looking for the beatnote as I adjust the digital temperature offset, but haven't found it yet...
If this proves totally fruitless, we can just put the lasers back to their original temperatures, since it's unclear if it helped the PC drive noise levels.
Meh. I've searched in steps of 20 counts in C1:GCX-SLOW_SERVO2_OFFSET units (16 bit +\- 10V DAC, and 1GHz/V coeffecient for the Xgreen aux laser means this is ~0.6MHz per 20 count step). I went from -400cts to +800 cts and haven't found the beatnote yet. Meh.
Both PSL green and Xgreen beams are going to the Xgreen BBPD. Both beams are easily visible, so while I didn't actually measure the power, it should be sufficient. The arm is being re-locked in green for each step, but it's not locked in IR, but that doesn't matter for just finding the beatnote.
I've got the output of the BBPD directly connected to the 50 ohm input of the HP8591E spectrum analyzer, with the freq span from 10MHz to 120MHz. The BBPD is supposed to be good up to ~100MHz, so I should catch any beatnote that's there. I have to head out, so I guess I'll continue the search tomorrow.
One of Kiwamu's suggestions was that, since no one is using the Ygreen concurrent with my fiddling, I rotate the waveplate after the PSL doubling oven so that max power goes to the Xgreen path, thus giving myself a bigger signal. I'll try that tomorrow. Today, I didn't ever touch the waveplate.
There are no more double sided tape on this table.