Jim Krishna Hugh
The gain was too close to the UGF and there was very little margin. The zero in the boost where it meets the main controller was lowered from 1.75 to 0.75 hz. This lowered the boosted gain but it is only a position loop anyway.
I have created an MEDM showing the Guardian states for each suspension. It is linked from the SITEMAP screen through the GRD pull down menu.
Earlier this week I revisited tilt decoupling at ETMX. I thought that maybe since the local to cart matrices had been modified since the tilt decoupling was done, maybe the align elements would need tweaking. Happily (or not as I had hoped this would explain why Krishna's tilt subtraction wasn't working as well as it could) everything stil looks pretty good. Attached plots are for X, first is the tilt measurement, red off, blue on. Second pic is the flex modes from the T240s for the tilt off measurement, they didn't appear to change for on or off. I did Y as well. Everything is in the ETMX/Misc/TIlt_Decoupling folder of the SVN.
TCS: Aidan is leaving today. Alistar will continue TSC commissioning next week. PEM: Filiberto pulling PEM cables at both end stations. PCal: Travis will be working on PCal cameras at both end stations. Commissioning: In addition to general commissioning, Keita is working on the PR2 clipping problem. Charge Testing: Rai W. continues working on charge testing experiment at End-Y.
Last night, we tried Z HEPI sensor correction on the BS. It did not go well. When I look at the data this morning, I didn't see the usual reduction in Z motion on the ISI seismometers, with low frequency re-injection. Instead, all we got was bad low frequency reinjection. The attached PDF shows performance from last night on the first 2 pages, with perfromance from the previous night on the last 2. The attached png shows the coherence between the ground STS and the ISI's St1 T240's. The solid lines are with sensor correction on, dashed are with sensor correction off. For some reason turning on Z sensor correction reduces coherence in the Y direction. Jeff and Fabrice have both suggested that maybe the op-lev damping is interfering with the sensor correction. The ground STS that was used for the sensor correction also is having issues, which Hugh has noted before. We'll keep digging.
The table below shows a comparison of the optical levers motion meaured during the five mornings of this week. We used ETMX to evaluate several configurations:
- Monday Oct 27, 3am - 4am, ETMX Stage 1 Z in Low Blend, Sensor Correction Off
- Tuesday Oct 28, 3am - 4am, ETMX Stage 1 Z in Low Blend, Sensor Correction Off
- Wednesday Oct 29, 3am - 4am, ETMX Stage 1 Z in High Blend, Sensor Correction Off
- Thursday Oct 30, 3am - 4am, ETMX Stage 1 Z in Low Blend, Sensor Correction On
- Friday Oct 31, 3am - 4am, ETMX Stage 1 Z in Low Blend, Sensor Correction On. BS sensor correction also ON (BS servo still engaged)
(Jim, please correct if my description of the controls configurations is inacurate)
Results: optical levers RMS motion
ETMX (Pitch/Yaw) Other test masses average (Pitch/Yaw) BS - Op Lev servoed (Pitch/Yaw)
Monday 15nrad /20nRad 30nrad / 30nRad 20nrad / 10nRad
Tuesday 20nrad / 35nRad 35nrad / 35nRad 15nrad / 35nRad
Wednesday 100nrad / 15nRad 40nrad / 35nRad 15nrad / 10nRad
Thursday 12nrad / 10nRad 30 nrad / 40nRad 13nrad / 10nRad
Friday 30 nrad / 10 nRad 30 nrad / 30 nRad 50 nrad / 50 nRad
Comments:
- On Monday and Tuesday, ETMX pitch motion was better than the other test masses, even though using the same configuration
- Wednesday results on ETMX show why we need to blend low on Stage 1 Z to reduce the pictch motion (at the cost of amplifying Yaw)
- Thursday results on ETMX with Sensor Correction On are excellent. The angular motion is as low as on the BS that is servoed.
- Friday results on ETMX are not as good in Pitch as the night before, but it is still much lower than usual in Yaw. The angular motion BS is very high. We might want to disable the op lev servo while testing the sensor correction on this unit. Jim is about to comment on BS sensor coreection activities.
M. Coughlin, K. Venkateswara
Michael noticed the earthquake on October 14th (M7.3 off of Nicaragua) was nicely visible in the seismometers and the BRS. I have attached the timeseries plots. I've also attached ASD plots of about 2 hours of data during the earthquake. GPS time = 1097293900.
The first ASD plot shows the T240X and the BRS RY out signals. Our guess for the horizontal displacement coupling was about 2e-4 rad/m. Multiplying this number with the T240 displacement output gives the red curve in the second plot. This seems to explain the signal in the BRS very well. The plot also shows the approximate estimate of the expected tilt signal assuming
theta ~ (2pi/wavelength) * X
where wavelength = velocity / frequency (assuming sound velocity of 5 km/s). This gives the light blue curve, which is a factor of ~5 below the displacement coupling in the 50-100 mHz range.
The third plot also shows the residual between the BRS RY out and the displacement coupling which is close to the light blue curve, but without knowing the displacement coupling in an independent measurement, we cannot estimate the tilt component. The fourth plot shows the coherence between the two instruments.
This is a good confirmation of the expected horizontal displacement coupling in the BRS and a measurement of the distance between the COM and the pivot, which appears to be 30 +/-5 micrometers. If |d| had been <3 micrometers, this would have enabled a direct measurement of the tilt component of earthquakes.
no restarts reported.
Lisa, Rana, Evan, Sheila, Chris, Kiwamu,
The DRMI was stable tonight. So we did several attempts for reducing the CARM offset and the smallest we got tonight was 125 Hz in IR. We will performe careful analysis of lock losses tomorrow.
Lock loss events to lock at are: 7:59:30, 8:11:09 and 8:56 UTC. The second one reached 200 Hz in IR and the last reached 125 Hz. We decreased the MICH gain from 7.9 to 3.0 because its UGF was found to be too high when the arm cavities were held at a off resonant point. According to the lockin demodulators, all the loops stayed without a significant gain change or anything. ALS COMM seemed to tend to lose its lock when it is "IR FINE TUNE". We need to investigate what causes lock losses.
I made an offline analysis of the last lock loss event.
It looks like some kind of instability happened and all the three loops oscillated at 5 or 6 Hz. Since all of them showed similar oscillatory behavior, it is difficult point out which loop was unstable. My guess is that this instability was induced by alignment fluctuation of the DRMI which eventually resulted in a mod hop in SRC -- the hopping-ish events are visible between t= -2.2 and -2.0 where POP18 is glitchy and AS90 went to negative and positive values back and forth. The CARM offset was set to 125 Hz in IR at this time.
As requested by Jim, I loaded the filters in BS HEPI and then ran the Switch_To_Test.py for setting the BS ISI to the test configuration at around 9:05 in UTC or 2:05 in PDT. Note that the oplev damping loops are running.
Peter F, Rana, Kiwamu,
As a preparation for the full lock study, we experimentally tried adjusting good coefficients for decoupling MICH from the other two in the LSC output matrix. Here are the results.
Precision for the PR2 and SR2 coefficients seem to be roughly a few % and 10 % respectively.
(Adjusting coefficients using the realtime lockin oscillators and demodulators)
We used the LSC realtime lockin oscillators and demodulators to find out the good output matrix for MICH. We drove BS at 131 Hz with an amplitude of 1000 cnts. At first, in order to find out the coefficient for removing PRCL out of MICH, we locked the sideband PRMI. We shook the M2 stage of both BS and PR2 in the longitudinal while changing the coefficient for PR2 manually until in-phase signal vanished at REFLAIR_RF45. We, of course, assumed REFLAIR_RF45 to be well tuned in its demod phase. Before the measurement we copied BS's inversion filter over to PR2 such that their frequency responses as seen from the LSC frontend are identical. In PR2, all other filters should be off and gain should be just unity.
Moving onto DRMI, we then shook PR2, BS and SR2. The coefficients for PR2 and BS were set to 1.0 and 0.02 so that we shake MICH more purely. Experimentally adjusting the coefficient for SR2, we found it to -0.014. The sign is negative because the effect of BS onto PRCL and SRCL are different and therefore it makes sense. We don't know why the PRC and SRC coefficients are different by 40% or so.
(Some tricks in SR2 M2 stage)
So for the setup in SR2, since one of the coil actuators had been dead, we used only LL and UR coils such that they still actuate without a large cross-couplings to the angular degrees of freedom at a cost of losing the half of actuation efficiency. This factor of two was then compensated in the Euler matrix by increasing them by a factor of two. We also copied the same BS inversion filter to SR2.
Rana, Kiwamu, Lisa, Alexa, Sheila, Evan
We took some time to measure the 1f and 3f DRMI sensing matrices.
To do this, we used the digital lock-in oscillators on the LSC screen to feed back onto some of the DRMI optics (PR2, SRM, BS, and a combination of 1×BS + 0.02×PR2 that we refer to below as BS+PR2).
The procedure was as follows:
cdsutils servo -r LSC-LOCKIN_1_DEMOD_5_Q_OUTPUT -g -10 -s 0 -t 100 LSC-LOCKIN_1_DEMOD_5_PHASE.z avg -s 8 to average them.Results for the 1f sensing matrix are as follows. The drive amplitudes have been divided out (and the entire matrix normalized).
| 1f | PR2 | SRM | BS | BS+PR2 |
| 9I | 2604(2) | 0.136(4) | −51.60(9) | −3.56(2) |
| 9Q | 107.5(9) | −0.0364(3) | −2.254(15) | −0.035(2) |
| 45I | 2015(4) | −3.70(4) | −39.69(6) | −5.51(5) |
| 45Q | −693(7) | −0.469(6) | 29.58(8) | 18.70(5) |
The matrix elements for SRM (in red) are probably bogus, because we were saturating the SRM actuator while driving.
Then we repeated this for the 3f signals, with REFLAIR27I→DEMOD 11, REFLAIR27Q→DEMOD 12, REFLAIR135I→DEMOD 13, and REFLAIR135Q→DEMOD 14. The drive amplitudes were 15, 9333, and 1999 counts for PR2, SRM, and BS. The results are as follows. Again the drive amplitudes have been divided out (and the entire matrix normalized).
| 3f | PR2 | SRM | BS |
| 27I | 9400(40) | −2.560(11) | −173.5(3) |
| 27Q | −154(8) | 0.618(9) | 14.72(5) |
| 135I | 2940(50) | −7.96(7) | −58.3(5) |
| 135Q | −22 550(90) | −0.17(7) | 543(2) |
DRMI lost lock before we were able to get the BS+PR2 measurement for 3f.
Kiwamu did some work to figure out what output matrix values are needed to drive mostly MICH; it is 1×BS + 0.02×PR2 − 0.014×SRM. Rana then measured the sensing matrix with 333 counts on MICH, 17 counts on PRM, and 18999 counts on SRM (and without saturation). WFS were engaged, and the loops were notched at the drive frequency (131.7 Hz).
Here is the 1f sensing matrix, with the drives appropriately divided out.
| 1f | MICH | PR2 | SRM |
| 9I | 0.921(26) | 1329.0(3.4) | 0.04300(70) |
| 9Q | 0.1122(58) | 76.43(46) | -0.02287(16) |
| 45I | 0.234(76) | 1635.6(3.1) | -3.3273(58) |
| 45Q | 20.922(62) | -262.6(5.7) | -0.4903(13) |
And likewise for 3f.
| 3f | MICH | PR2 | SRM |
| 27I | 4.32(21) | 5410.9(5.8) | -1.7543(47) |
| 27Q | 8.431(72) | -157.0(2.5) | 0.4443(43) |
| 135I | -8.5(2.1) | 1389.4(22.9) | -7.289(59) |
| 135Q | 125.6(2.4) | -12638.3(77.9) | -0.135(63) |
Also last night, we took similar measurements of the PR2/SR2 portions of the DRMI sensing matrices while we tried bringing in the arms. Sheila started at ≈ 7.5 nm and over a few minutes brought the arms to slightly under 4 nm, at which point we lost lock (the conversion from displacement to detuning is 7 nm / Hzgreen). So the attached plots should be read from left to right.
The big jump at 6.5 nm is because Kiwamu had to tune up the DRMI alignment to prevent lock loss. So the jump in the sening matrix elements isn't surprising. Beyond that, the values appear more or less constant, to within uncertainty.
It seems as though an oscialltion in the BS (visible on the stage 2 GS13) caused a DRMI lock loss. The oscillation seems to be in the ISI channels, but I don't see it in the control signals or on the OpLevs.
HAM3 also just tripped, we don't think there is anyone in the LVEA right now
Chris, Kiwamu, Suresh, Sheila
We have had several more of these odd HAM3 trips tonight. We chased it down to a problem in the IMC_LOCK guardian, where a huge impulse is sent to MC2 in the down state. We are strongly suspicious of a the lines where the gain of MC2_M2_LOCK_L and M1_LOCK_L are set to zero, and the integrator in M1 and boost in M2 are switched off. Both of these filters are switched with zero history, immediately. We changed the boost in M2 to have the output ramped off over 5 seconds. We also changed the code to nicely clear the integrator in M1:
ezca.switch('SUS-MC2_M1_LOCK_L', 'INPUT', 'OFF')
ezca.get_LIGOFilter('SUS-MC2_M1_LOCK_L').ramp_gain(0, 5)
ezca['SUS-MC2_M1_LOCK_L_RSET'] = 2
ezca.switch('SUS-MC2_M1_LOCK_L', 'FM1', 'OFF')
ezca['SUS-MC2_M1_LOCK_L_GAIN'] = -1
We haven't loaded this, since by the time we figured this out we had already moved onto locking DRMI.
One thing that is different tonight is that we started trying to use the ISC_LOCK guardian, which is managing the IMC_LOCK guardian. It's not clear why this would have caused these kicks to the IMC. There is some kind of bug in the way that the ISC_LOCK is managing its subordinates, so sometimes they hang up, and do not leave a state which has finished even though there is a path to the requested state.
Fixing this problem in the ISC guardian may help to prevent the HAM ISI trips that we have occasionally had on restarting beckhoff code.
Continuing a trend of stealing from LLO without shame, I looked at the L1 ISI foton file (via LLO's DAQ svn) to see what filters they were using for St1 sensor correction. I've attached some plots comparing some of the filters. It would be helpful if someone at LLO could summarize (again) what is being used in a complete and accurate way, because some of the filters have very similar names. FF is a common name for different filters. In the first plot, the green (I think) line is the sensor correction a version of the filter Rich Mittleman designed, that we have been using at ETMX with the BRS. The other lines, with an rdr are Ryans filters that I found in the LLO ITMY foton file, which I named based on what direction I found them. Second plot is the phases of same filters, with the same color scheme and order.
zpk's for the different filters:
rdr X,Y & Z Senscor
zpk([0.005868986282643151+i*0.005869222531082809;0.005868986282643151-i*0.005869222531082809;0;0;0;
0],[0.02121320343296193+i*0.0212131204375177;0.02121320343296193-i*0.0212131204375177;0;0;
5.326821252114442e-10;0.03999999945769176;0.0999999989897627;1.299999570000159;
6.999932741807108],6217465930.447066,"n")
rdr Y Senscor
zpk([0.006840399999901201+i*0.01879390059988029;0.006840399999901201-i*0.01879390059988029;
0.06062180000003715+i*0.03500000003808696;0.06062180000003715-i*0.03500000003808696;0],
[0.01368079999995818+i*0.03758769978878637;0.01368079999995818-i*0.03758769978878637;
0.03500000000007082+i*0.0606217999686012;0.03500000000007082-i*0.0606217999686012;
0.01000000066387688;0.03999999933609382],99.46935875676593,"n")
Mittleman Senscor
zpk([0.05785089999994956+i*0.06894400006181636;0.05785089999994956-i*0.06894400006181636;0;0;
1.054942208843087e-09;0.009999998945009785],
[0.003420200000103372+i*0.00939692986876447;0.003420200000103372-i*0.00939692986876447;
0.01267849999986304+i*0.02718920009938821;0.01267849999986304-i*0.02718920009938821;
0.04499510000006567+i*0.05362309993610679;0.04499510000006567-i*0.05362309993610679;
0.005000000000048375],0.006161864174656091,"n")
rdr Z Senscor
zpk([0;0;0],[0.003535529999897033+i*0.003535531890194072;0.003535529999897033-i*0.003535531890194072;
0.000868241000053361+i*0.004924041464289278;0.000868241000053361-i*0.004924041464289278;
50.0000000000001],252959718.8553666,"n")
The "Mittleman" and rdr Z" Filters (pink and green?) are both for use only with Z or a tilt correct tranlsation signal using Krishna's tilt meter.
The red, "rdr X,Y & Z" is Ryans 0.5Hz notch filter deisgned to be used in parallel with low frequency stage 1 feedback.
The blue is a substitute for the FIR filter chain(the FIR filter probably is better), obvously has a different sign from the others.
08:00 resarted Alarm Handlers; CDS overview: noticed some conflicting counts on fw1 and some timing flags at the mid station; Vacuum: noticed IP-01 flashing red. Sent out emails to the corresponding folks for a check-out.
08:30 ISS loop coming in and out of saturation. Diffracted power all over the place. I bumped the refsignal up a click and the diff power stabilized. I tried a series of clicks following and got the diff power back up to ~7.6%
09:09 Betsy and Travis out to West bay to work on 3IFO Quad.
09:10 Andres out to W Bay
09:20 Peter F out to LVEA
09:55 J Bartlett, also Andres out of LVEA
10:25 Ryan reported a possible network outage lasting ~10 minutes maybe upstream of PM&L
? Alastair putting power meter on TCS X arm table (WP 4925)
11:12 Robert working in beamtube between mid Y and end Y (shaking tests)
11:21 Dan to end X to look for equipment
11:56 Shivaraj to end X and end Y to mount magnetometers on tripods
12:38 ISS first loop went erratic again until ~
13:19 Karen at end Y
13:51 Karen out of end Y
14:30 Dan H out to HAM6
15:20 Rana brought to my attention folks entering VEA areas. Not everyone is reporting their desire to enter to the operator. Cleaning personell are calling after they've arrived at end stations.
The ISS loop was sporadic all afternoon
J. Kissel, R. Abbott Was checking the status of the ETMX optical lever against Doug's status report (see LHO aLOG 14711) before I took some measurements using it, and found that the ETMX optical lever's compensation filters (i.e. H1:SUS-ETMX_L3_OPLEV_SEG?) have to filters, "gain2" and "gain1.4" (which are gains of 0.5 and 0.707, respectively) that are turned ON. I couldn't find any aLOGs about these filters, and it doesn't really make sense to me to compensate for any analog gain, given that we normalize by the SUM. Anyone know anything about this? %%%%%%%%%% EDIT %%%%%%%%%%% Doug's status chart reports values exactly backwards and bit-shifted up 1. "HIGH" bits are LO, and "B1" = B0. The confusion arised from Evan's convention for high vs. low, and that the switches are numbered starting at 0 on the board, and 1 right next to the switch. Therefore, the ETMX is compensated for correctly. Will post corrected assessment shortly. %%%%%%%%%% Historical Log, for future reference %%%%%%%%%%%%% Piecing together the puzzle, from Doug's aLOG (LHO aLOG 14711), and the various circuit schematics (Configuration Daughter Board D1001631, Chassis Assembly, ), Evan's recent PR3 tune up (LHO aLOG 14631), my aLOG from many moons ago (LHO aLOG 3619), and a phone call to R. Abbott, I can determine that having each channel in the following configuration (as indicated by Doug's aLOG, where B0-B7 is the configuration for the first channel, and the remaining 3 channels, B8-B15, B16-B23, and B24-31 are in the same configuration), Switch Function Setting Status Name HI LO B0 G = 24 [dB] X ON B1 G = 12 [dB] X ON B2 G = 6 [dB] X OFF B3 G = 3 [dB] X OFF B4 1:10 Whitening X ON B5 1:10 Whitening X OFF B6 1:10 Whitening X ON B7 Latch X ON Note -- and this seems to be a common misconception -- when the switch is LO (or "0", or away from the chassis as installed) the switch is ON / ENGAGED. Therefore, the total transfer function: G = 36 [dB], two stages of (1:10) whitening. (filter zero and pole notation is (z:p) -- note that the poles and zeros is INCORRECT [i.e. inverted] in my old aLOG) Thus, the current compensation scheme, with FM1 (10:1) with FM4 and 5 (the "gain" filters mentioned above), it seems as though the switches have been interpreted in exactly the opposite fashion as the schematic intends. Even worse -- the LATCH is ON, which means it's actually telling the board to engage whatever the settings were *before* the latch were engaged, and the current status of the bits B0 through B7 DON'T MATTER. #facepalm Will get with Rana / Evan / Doug / Jason about this.
PeterF, Rana
We checked out the SR3 optical lever signals and determined that we needed to turn on one stage of whitening (1:10) and no whitening gain stages to get us cleanly above ADC noise everywhere.
Based on the TCSX central heating calibration (62.3 micro-diopters single-pass per Watt) and the calculated static lens of -80213m, we require:
Edited 31-Oct-2014: this isn't correct because of an error in the laser power calibration
The calibration of defocus vs delivered power is incorrect as the delivered power channel, H1:TCS-ITMX_CO2_LSRPWR_MTR_OUTPUT, was not calibrated correctly.
I went back and reviewed the delivered power for this measurement:
Before thermal lens: H1:TCS-ITMX_CO2_LSRPWR_MTR_INMON = 172.7 counts
During thermal lens H1:TCS-ITMX_CO2_LSRPWR_MTR_INMON = 2113.4 counts
The new gain through the filter banks is 7.2087E-4 Watts per count.
This means 1.399 Watts was applied to ITMX during the thermal lens measurement.
Further analysis of the HWS measurements of the thermal lens show:
Based on the TCSX central heating calibration and the calculated static lens of -80213m, we require:
Optical Lever Whitening Chassis Rack Locations and Chassis Locations and Current Binary Output Module Status at LHO: D.Cook 10/29/2014 Rack SUS H1-R1: Chassis cabled - Board 1- HAM 2 = No BOM installed Chassis cabled - Board 2- HAM 3 = No BOM installed Rack SUS H1-R2: Chassis cabled - Board 1- HAM 2 = No BOM installed Chassis cabled - Board 2- PR3 = BOM installed B1, B2, B4, B9, B10, B12, 17, B18, B20, B25, 26, B28 set HIGH (the rest set LOW) Rack SUS H1-R3: Chassis cabled - Board 1- HAM 5 = No BOM installed Board 2- SR3 = BOM installed B4, B12, B20, B28 set HIGH Rack SUS H1-R4: Chassis cabled - Board 1- HAM 4 = No BOM installed Chassis not cabled - Board 2- Empty Rack SUS H1-R5: Chassis cabled - Board 1- BSC 8 Pier (temp ?) = No BOM installed (jumpered connecter) Chassis cabled - Board 2- BS = BOM installed B1, B3, B4, B9, B11, B12, 17, B19, B20, B25, 27, B28 set HIGH (the rest set LOW) Rack SUS H1-R6: Chassis cabled - Board 1- ITMx = BOM installed B4, B5, B12, 13, B20, B21, B28, B29 set HIGH (the rest set LOW) Chassis not cabled - Board 2- Empty Rack SUS H1-R1 ETMy: Chassis cabled - Board 1- ETMy = BOM installed B4, B5, B12, 13, B20, B21, B28, B29 set HIGH (the rest set LOW) Chassis not cabled - Board 2- Empty Rack SUS H1-R1 ETMx: Chassis cabled - Board 1- ETMx = BOM installed B2, B3, B5, B10, B11, B13, B18, B19, B21, B26, B27, B29 set HIGH (the rest set LOW) Chassis not cabled - Board 2- Empty
This entry has several bugs making the data incorrect. A corrected status chart can be found in LHO aLOG 14749
Here is before and after plots--it seems pretty obvious that this was a problem. Very interesting how it affects things below 100mHz--see Krishna's alog. The first is before, the second after the change.--Need to svn the foton file.