Today's acitvities reported to the operator:
- Kyle R to LVEA to soft close GV5.
- Corey G and Keita K, working at End-X, TMS related work.
- Thomas V to work on ITM-Y OpLev, maintenance. Shutter between PSL enclosure and HAM01 was locked while work was done.
- Scott S, Mitch R and Lisa A, AOS/SLC Team to LVEA, End-X ACB build up.
- Betsy W and Travis S, End-X SUS work.
- Kiwamu I, to LVEA, check ISC table contents.
- Pablo D, Colin S and Craig C, work in the H2 PSL enclosure.
- Patrick T to both End stations, dust monitor work.
- Thomas V to remove lock from light pipe.
- Kyle R, to open GV5.
The dust monitors in the LVEA are NOT currently being recorded. It appears swapping the dust monitor in the H1 PSL enclosure has broken the communications.
Today we installed 2 more accelerometers on the PSL table, one by where the water enters the high-power amplifier and the other by the PMC. We also removed the cover from the PMC. In addition we switched out the dust monitor which has been giving a calibration error message for some time (the 300 and 500 nm cutoffs may not be well calibrated). And we put up some signage related to switching between commissioning and science mode.
Attached are a set of directions for switching the PSL HVAC system between science and commissioning modes. These are also posted at the PSL. In science mode, only the make-up air, the air that pressurizes the PSL to exclude dust, is working, and only at 20% of capacity. In commissioning mode the make-up air is set at 100%, the HEPA fans are turned on to reduce dust, and the air conditioning is turned on to handle the heat load. The 20% make-up air setting does not seem to increase the dust load in the laser room, but the dust load does increase in the anteroom because the HEPA filters are off and there is no overpressure to keep dust from the LVEA out. Figure 1 shows 60 days of dust monitoring in the PSL laser room and the anteroom – most of the plotted time is in full commissioning mode, but the last three days (blue underline) show the dust status in science mode.
Nothing coming from the h1iscey model is updating. Jeff tried restating the model, then restating h1iopiscey, its still not running.
S. Dwyer, J. Kissel Knowing little about the iscey computer or its contents, but recognizing the frozen EPICs values, I had suggested that Shiela try to restart the front end process. After this had failed to solve the problem, I suggested taking down all of the user models and restarting the IOP process (note that this includes H1SUSPEMEY; sorry Robert). When the IOP process came back up from the start up, it complained of having NO SYNC, and all of its EPICs values had not kick started. Since this could be a problem that ranges in severity from "you jus need to hard boot the computer" to "the timing has crashed for this computer," we've decided -- after a days worth of debugging cavities -- that we'll just leave it for the expertise of the CDS crew tomorrow morning. We've left H1ISCEY with a hung but "running" IOP process, and dead user models. No Arm Cavity locking for tonight, kids.
[Stefan, Jeff K., Kiwamu]
We have aligned the BS this afternoon to maximize the amount of H1:ALS-C_TRY_A_DC.
This took some time since there was some confusion in the BS oplev and BS HEPI.
Current alignment biases :
H1:SUS-BS_M1_OPTICALIGN_P_OFFSET = -23
H1:SUS-BS_M1_OPTICALIGN_Y_OFFSET = 9
Current oplev nominal readout :
H1:SUS-BS_M3_OPLEV_PIT_OUTPUT ~ 5
H1:SUS-BS_M3_OPLEV_YAW_OUTPUT ~ 52
After aligning BS, H1:ALS-C_TRY_A_DC_VOLTS went to 0.3 which is higher than the value these days by a factor of 3. Also I see the red transmitted light becoming brighter as I aligned BS. This indicates that we are going back to the previous good alignment.
Before maximizing it we accidentally screwed up the BS alignment. It seems before Thomas centered the BS oplev the BS HEPI tripped for some reason. Therefore unfortunately the oplev centering was done with the wrong alignment. This complicated our alignment. Jeff untripped the BS HEPI with the intentional offsets enabled in V1 and V4 actuators which is the nominal configuration these days. Then we recovered the BS alignment by adjusting the top mass alignment biases. At the beginning we brought BS to roughly a good alignment by looking at the oplev trend and subtracting the offset introduced by the centering business. A fine alignment was done by maximizing H1:ALS-C_TRY_A_DC.
We were able to get H1:HPI-BS (in BSC2) running on Level 2, by - Running "ctrlDown BS" - Resetting all watchdogs - Turning on the master switch - Slowly ramping on the offsets using the master gain (which appears not to be controlled or used by the command scripts) - Hitting "isolate BS lvl2" The offsets buried in the V1 and V4 actuator filter banks, which are +2000 and -10000, respectively, were the major source of the H1 SUS BS misalignment. In case you missed it (like I did), Of the HEPIs involved in HIFO-Y, H1 HPI ETMY (in BSC6) H1 HPI BS (in BSC2) H1 HPI HAM1 are unlocked and floating, and controllable. H1 HPI ITMY (in BSC1) H1 HPI HAM2 H1 HPI HAM3 are locked.
I fixed a minor naming cut-n-paste error in h1iopsusex. I restarted all the SUS EX models to install the change. We will complete this modification tomorrow when we restart the DAQ (EDCU is purple partly due to this).
The EX software watchdog medm screen was created.
The daqd on x1dc0, x1nds1, and x1fw1 has been built from branch 2.7 and the data concentrator has been restarted to run the branch 2.7 versions.
JimW added another ~281 lbs to HAM6 and this got the lockers in the 'nearly loose' region. Temporary Viton was added under all masses. With it still locked, we then checked the Optical Table level and found it ~35mils runout. We loosened all the Horz HEPI set screws and then dropped the West-side corners ~1/32". This lowered the runout to <10mils and that is good enough to work on the ISI Lock/Unlock/Balancing. The HEPI Set Screws were resecured. Jim then worked on setting the Vertical CPS gaps/alignment. There may be a CPS Rack issue we need FClara to address tomorrow.
The x1work computer on the DTS is now running Ubuntu 12.04, updated from Ubuntu 10.04. A 1T hard drive was added as /data for database testing. Ubuntu 12.04 was installed on a separate 250G drive, the old Ubuntu 10.04 disk has been mounted as /usr1 in case there are files that need to be transferred to the new disk. Application software has been updated to the same software running in the LHO control room. The RSA fingerprint for x1work is now d5:ff:79:df:74:73:00:5e:89:06:ce:65:3d:8b:34:17
Daniel Halbe, Jess McIver
Daniel has shown a strong, persistent line at 6.8 Hz in all DOFs of the top stage BOSEMs of the ITMY since at least June 12.
As a follow up to his study, I looked for this line in the ITMY ISI and found it in stage 2: very sharply in RX, strongly in RY, somewhat fainter in Z, and much quieter in X, Y, and RZ.
The line is not seen in any DOF in stage 1, looking at the T240s.
Normalized spectrograms of representative DOFs are attached.
I have discovered a line very similar to this at Livingston and it occurs at 7 Hz. This line is found in Roll (very strongly) and not as strong in pitch. It appears to only show up in those two degrees of freedom and only in the top SUS mass. It does not show up in the ISIWIT channels or the top stage of the ISI. Also it does not show up in any of the other suspension stages.
I looked at spectrograms, time series, and ASDs for the CPS sensors on ST2 of the H1 ITMY ISI in all global degrees of freedom, but saw no evidence for a line at 6.8 Hz. An ASD of each CPS DOF during this time is attached in .fig form.
Alexa Sheila Stefan The I mon of the demod was not broken; I was using a bad cable to look at it. Now we are using the original demod again, using the I output, and the I mon and Q mon are on the scope visible from the ceiling camera (Imon is the x axis, Q mon is Y, both 500mV/div) We have the phase shifter still on external (remote controlled); the phase we are using now is 107.82 degrees and on the servo board IN1 polarity is negative. Right now we are locked with a gain of -8dB, and a screen shot of the IQ polar plot is attached. There is a lot of noise in I.
To date and the best of my knowledge, the only measurements of the 18-bit DAC noise have been those performed by J. Heefner, documented in T0900338, where the DAC noise is quoted as 150 [nV/rtHz] (and flat in the frequency band he probed). We'd learned from eLIGO (lessons by Tobin, myself,Matt, and Nic) that a DAC's noise floor changes when excitation is present, so Jay had measured the DAC noise while injecting a single-frequency line at ~100 [Hz], and then measured the high-frequency asymptote (his plots are on a linear x axis, without a grid so one can really only see the results above 100 Hz). In the interest of suspension performance in the 0.1-10 [Hz] band where cavities are currently sensitive to their optic's motion, I've now characterized the noise in detail at low-frequency (0.05-1e3 [Hz], with focus on 0.05-50 [Hz] band), using a realistic output spectrum as the requested voltage. The results are attached and described below. Since the results are clearly non-linear, we may need to try different input spectra (working a little harder than I did to balance the SR785 range vs. noise) to really understand it. Naturally, we should also develop a model of the quantization noise, to see if we can differentiate this from just bad, non-linear electronics noise. Finally, we should also perform this same measurements on a 16-bit DAC. Note that, by default, the user-model-to-IOP-model exchange is done with zero-padding, as has become the default configuration for all models. -------- Plots and Captions 2013-07-21_2119_H1SUSMC2_DACOutput_ModeCleanerLocked_ASDs.pdf During a fully functional Input Mode Cleaner lock, this is the output voltage requested of the DAC at all three stages. The spectra seen at the TOP/M1 stage is totally confusing to me, so I ignored it, as it was distracting to this study to try and figure out. More on that to come later. As such, (and also informed by the input range vs. noise floor of the SR785 at these frequencies), I chose the Middle / M2 stage spectra as my representative spectra. experimentalsetup.pdf Diagram of how the experiment was set up. For this study, I commandeered the H1 SUS QUAD Test Stand. This is a fully-production quality test stand, running up-to-date software, and up to which nothing is hooked, so it was the perfect test bed. The Pomona box that was used to switch between output channels (borrowed from MIT) was a easy, convenient way to grab the signals, keeping them shielded, without having to mess with the usual breakout boards and clip leads -- a set up usually fraught with excess unwanted noise. 2013-07-21_H1SUSQUADTST_DACNoise.pdf The Results PG1: Here is the digitally requested spectrum, calibrated into voltage out of the AI filter (i.e. cts at the COILOUTF_??_EXC point, multiplied by the gain of the DAC, 20 / 2^18 [V/ct]). It is compared with the measurement noise floor (for the low-frequency, 0.05 - 50 [Hz] band, with -10 [dBVpk] SR785 input range), and the measured DAC noise with no digital output requested. The "traveling notches" in the requested drive are used to carve out at the DAC noise without disrupting the main frequency content of the signal. Note that because of SR785 range vs. noise issues, I sent out a requested signal with a factor of 10 less RMS voltage at 1e-2 [Vrms]. This is compared with the M2 stage (with 1e-1 [Vrms]) and PG2 - 4: The measured DAC noise output at the AI chassis for 3 DAC channels. We see, rather obviously that none of the notches below 10 [Hz], indicating a several elevated DAC noise floor. I've included a quick by-eye fit to the noise, which indicates that the DAC noise is 6e-6 * (10 [Hz] / f) [V/rtHz], with this excitation. Notes: - Even though the SR785 measurement is focused on the 0.05 - 50 [Hz] band, the full spectrum out to several [kHz] is requested during all measurements. - It's unclear to me why the shape and level of the DAC noise changes when I switch to the higher measurement band (10 to 810 [Hz]). Since I saw the DAC noise floor after the natural 100 [Hz] roll-off of the output spectra while retaining the 30 [Hz] notch (and it was Sunday at 8pm), I didn't bother traveling the notch any further, and therefore only have one measurement for each channel in this band. ----------- Details: The template for the mode cleaner output request spectra can be found here: ${SusSVN}/sus/trunk/HSTS/H1/MC2/Common/Data/2013-07-21_2119_H1SUSMC2_DACOutput_ModeCleanerLocked_ASDs.xml The input spectra is defined by the following AWGGUI Foton String which filtered white ("uniform") noise: amplitude = 100000 to get 1e-2 [Vrms] zpk([1.3;1.3;1.3;1.3;1.3;1.3],[0.3;0.3;0.3;0.3;0.3;0.3],1,"n")ellip("LowPass",4,1,80,100) notch(0.47,10,200)notch(0.5,10,200)notch(0.52,10,200) notch(0.9,10,200)notch(1,10,200)notch(1.1,5,200) notch(4.7,10,200)notch(5,10,200)notch(5.2,5,200) notch(10,5,200)notch(11,5,200)notch(12,2.5,200) notch(30,5,200)notch(32,5,200)notch(34,2.5,200) I'm *sure* there's a more elegant way of defining it, but ... so it goes. The captured digital output spectra templates can be found here: ${SusSVN}/sus/trunk/QUAD/H1/QUADTST/Common/Data/18Bit_DACNoise_2013-07-21/ 2013-07-21_H1SUSQUADTST_DACNoise_COILOUTF_AvgASDw0p45-0p5-0p55HzTipleNotch_ASDs.xml 2013-07-21_H1SUSQUADTST_DACNoise_COILOUTF_AvgASDw0p9-1-1p1HzTipleNotch_ASDs.xml 2013-07-21_H1SUSQUADTST_DACNoise_COILOUTF_AvgASDw4p5-5-5p5HzTipleNotch_ASDs.xml 2013-07-21_H1SUSQUADTST_DACNoise_COILOUTF_AvgASDw10-11-12HzTipleNotch_ASDs.xml 2013-07-21_H1SUSQUADTST_DACNoise_COILOUTF_AvgASDw30-32-34HzTipleNotch_ASDs.xml The raw SR785 data files can be found here: ${SusSVN}/sus/trunk/QUAD/H1/QUADTST/Common/Data/18Bit_DACNoise_2013-07-21/SCRN*.TXT with a key to what each number means in ${SusSVN}/sus/trunk/QUAD/H1/QUADTST/Common/Data/18Bit_DACNoise_2013-07-21/2013-07-21_MeasNotes.txt The data is analyzed, and plots are produced with the following script: ${SusSVN}/sus/trunk/QUAD/H1/QUADTST/Common/Scripts/plot18bitdacnoise_20130721.m
I used Matlab to model the quantization noise associated with Jeff's measurement. Here's the punchline: The "hiFreq" measurement series is consistent with quantization noise. The excess noise seen in the "loFreq" measurements is not.
The attached plot tells the story. The blue curve (mostly submerged under the red one) is the spectrum of Jeff's excitation, calculated with double precision as the front end would do. The solid red curve is what you get after applying 4x interpolation, and rounding the signal so it matches the 18-bit precision of the DAC. The 18-bit curve overlaps the double-precision curve almost everywhere -- except in the bottom of the notch and past the cutoff of the LP filter. In those two places, it's limited by round-off error, also known as "quantization noise". This noise floor is shown by the dotted red curve, which is the spectrum of the double signal minus the 18-bit signal.
The black curves are taken from Jeff's measurements. For the solid curves, the excitation was on; for the dotted curves it was off (requested DAC output = 0). The dotted curves are presumably limited by the electronics noise of the DAC. As for the solid curves, the "hiFreq" data reaches the quantization noise limit in the notch and outside the LP cutoff. The "loFreq" data appears to be running into some other noise floor. As Jeff noticed, the loFreq and hiFreq curves suspiciously disagree about the depth of the notch.
Side notes
Suggested next steps
The dominant noise source of a low noise DAC, when driven near its full range is the integrated non-linearity (INL). The exact shape of this noise might depend on the exact drive, ie., it could very well be different for a broadband signal vs single frequency, it might look different for high vs low frequency drive signals.
Communication was lost with the dust monitor at end X, I believe last Friday. The IOC was reporting errors like 'Command not echoed: ' and a random symbol character. Corey power cycled the Comtrol at end X for me, but this did not fix it. I went out to end X and found the dust monitor moved and off. I checked the fuse and it was blown, so I replaced it. After resetting the front panel options I called Dave and he restarted the IOC. This fixed it. I also removed the dust monitor at location 2 at end Y that was reading counts even with the zero count purge filter attached. This dust monitor is labeled 'S'.
The SEI teams at Stanford and LASTI are currently testing the new Cartesian basis bias correction in the isi/common/isi2stagemaster.mdl. Please do not svn update the trunk/isi/common directory from the cds_user_apps repository without talking to someone locally from one of the SEI teams.
For more details, see the log entry made by Hugo Paris on Friday 19 July 2013 titled "BSC/HAM ISI Models & MEDM - CART BIAS Update" in the SEI log.
Charles Celerier
Stanford SEI Team
I changed the demod for the PDH at end y over to the second channel in the same chassis. For this I had to change an SMA cable, so the phase will have shifted. While I was there I had a look on the table to see if there was any evidence of clipping, I didn't see any although the beam is kind of close to the edge of the 2 inch beamsplitter right after the periscope. I also readjusted the centering on the refl PD, mostly in yaw (the beam wasn't far off). I set up the scope in XY mode with I mon on the X axis and Q mon on the Y axis so we can use that to retune the phase. Strangely, the RF level on the bbPD for the PLL dropped suddenly at around 19:05 UTC. I'm not sure why that happened, the crystal frequency offset sent by beckhoff did not change and the FSS seemed to be locked the whole time. I changed the temperature of the end station laser from 31.35C to 31.45C, the pll is locking fine now.
The existing ASC_CUST_TIPTILT_OVERVIEW_all.adl (intended to show an overview of all HTTS/TipTilts) had been a renamed version of SUS_CUST_HAUX_OVERVIEW_all.adl with no further adaption, so I got it working.
This involved renaming a lot of buttons, signals and related displays, applying the new calling conventions via macro text files for all related displays, and compacting the layout to allow squeezing in a fifth optic at the bottom.
The new screen has been committed and linked to the LHO SITEMAP.
LLO might want to svn up and link it also.