2:30 pm local Took 24 sec. to overfill CP3 by doubling LLCV to 36% open. TC plot attached.
Evan G., Keita K. Summary: We analyzed the measurements made at the end station (see LHO aLOG 30854). The measured delay of a 960 Hz digital sine wave excitation to the output of the analog AI is 205.7 usec. The expected delay is 203.6 usec. The difference of 2.1 usec could be the result of small differences in analog AA/AI electronics. The measurements also reveal the DAC delay = 63 usec (61 usec expected, again probably the difference is the small variability of the AA/AI electronics), ADC delay = approx. 1 usec (<1 usec expected). Additionally, digital excitations are found to be advanced by 61 usec. This is important because we need to independently measure the the timing of the analog signal relative to the witness GPS 1 PPS signal to determine the timing of the ADC. We also independently measure the timing of the DAC relative to the witness GPS 1 PPS signal by using the digital system to produce an excitation that is measured in the analog world. Details: The oscilloscope measurements are analyzed using the duotoneDelay.m script which directly computes the Fourier coefficients of a DuoTone time series with two sine wave signals at 960 and 961 Hz. The Fourier coefficients yield the amplitude and phase, where the phase delay is interpreted as a time delay. The time series input is synchronized to the 1 PPS signal from the witness GPS receiver located at each end station (time series is triggered on the rising edge of the 1 PPS). The oscilloscope is set to produce 1e6 samples per trace. We saved two different duration traces: 1 sec (1e6 samples/sec) and 2 sec (5e5 samples/sec). Oscilloscope ------------ 1 PPS --| CH1 | ==> Time series with pulse leading edge = 0 sec | | Pcal/DuoTone --| CH2 | ==> Fourier coefficient of time series with timestamps referenced to 1 PPS yields delay ------------ Analog measurement Delay (usec) ---------------------------------------- Pcal X excitation (1 sec) 145.2 Pcal X excitation (2 sec) 144.1 Pcal Y excitation (1 sec) 144.4 Pcal Y excitation (2 sec) 144.9 DuoTone X (1 sec) 257.9 DuoTone X (2 sec) 258.0 DuoTone Y (1 sec) 257.2 DuoTone Y (2 sec) 256.6 We saved a 2-second DTT time series of H1:CAL-PCAL*_DAC_FILT_DTONE_IN1_DQ and H1:CAL-PCAL*_EXC_SUM_DQ (where * = X or Y). The time series starts on an integer second. Using the same duotoneDelay.m script, we compute the delay of the digital Pcal excitation signals and the digital DuoTone signal. Digital measurement Delay (usec) ------------------------------------------------ H1:CAL_PCALX_EXC_SUM_DQ -61.0 H1:CAL_PCALY_EXC_SUM_DQ -61.0 H1:CAL-PCALX_DAC_FILT_DTONE_IN1_DQ 340.4 H1:CAL-PCALY_DAC_FILT_DTONE_IN1_DQ 339.8 (Note the 61 usec advance of the excitation signal) To determine the analog output delay of an excitation, we subtract the measured delay of the digital Pcal excitation from the measured analog delay and compute the mean value, yielding a delay of 205.7 usec. We expect a delay of 203.6 usec (61 usec delay from USER model to IOP model, 43.5 usec from phase effect in digital AI, 3 IOP DAC FIFO cycles, 0.5 IOP cycles from DAC zero-order-hold, 0.5 IOP cycles from DAC clock offset, and approx. 38 usec from phase effect in analog AI). The difference of 2.1 usec is likely due small differences in the analog AI filters. To determine the DAC delay, we can remove the analog and digital AI filtering, and the 61 usec delay from USER to IOP models. This yields a delay of 63 usec, compared to the expectation of 61 usec. The difference is, again, likely due to small differences in the analog AI filtering. The ADC delay can be determined using the difference between the measured delay of the DTONE_IN1_DQ channels and the delay measured in the analog DuoTone signals. We also need to remove the analog and digital AA filtering. This yields an ADC delay of approx 1 usec (we expect a delay of <1 usec). Small differences in the analog AA filtering may be the reason for this difference. Analysis script can be found at: /ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/PreER10/H1/Scripts/timing/analyzeTimingMeasurements.m
Summary: new ISS 2nd loop gain = 17 dB.
Since we have changed the amount of light on the inner loop PD (PDA, alog30871) and also decided to lock with an input light power of 25 W, these let us re-tune the gain of the ISS second loop. The goal of this adjustment is to maintain the intended UGF in the second loop. This morning, I have measured the open loop and adjusted the gain. The measurements were done with the IMC locked at 25 W and the second loop locked with the DC-coupling enabled. The inner loop was closed with a gain of 18 dB and a diffracted power of 4% as usual (30871).
The attached image shows the measured open loop transfer function of the ISS second loop. The UGF was tuned to 19 kHz (which used to be 18 kHz back in this September alog29915) where the phase margin is almost the same value of 45 deg. The gain margin is found to be 7 dB. Everything seems good. Additionally, the raw data files are attached.
I saw the lock degrading in the same way H1 had issues at the end of O1, and tweaked TMSX and TMSY to regain range and quiet arm powers.
Lock lasted 7+ hours.
Did we have a servo on TMS back then? Is it commissioned and running now?
Jim was trying some different EQ sensor correction filters on the HAMs yesterday. The operator, likely, reverted these to normal around 6pm. In the future, please make a log when this is done.
State of H1: locked in NLN 7 hours
Details / Activities:
My TCS alog 30955.
As I watch, range has held steady around 60MPc.
State of H1: Nominal Low Noise
Range: 68MPc
Target for changing TCS: 9:10UTC
PEM injections completed for tonight
State of H1: relcoked in Low Noise
Outgoing Ops: TJ
On Site: Robert, doing PEM injections in the LVEA
Details:
TITLE: 10/28 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Commissioning
INCOMING OPERATOR: Cheryl
SHIFT SUMMARY: Locking is much better than the past few days, the only thing to mention is that BS seems to be drifting in pitch at times. While locking DRMI I'll adjust it, and meanwhile AS90 will slowly drift down, adjusting the BS P again seems to bring it right back to was. After locklosses BS P always seemed to be off by a bit as well. The MICH ASC error signal seems to be the noisiest during lock, but maybe this is normal, I can't remember. I didn't want to mess up Robert while he was doing work so I haven't tried adjusting it to maybe correct for the downward trend in the range.
The PR2 Roll mode has been reduced in the DARM spectrum by adding 1Hz wide bandstops (centered at 40.9Hz) to all the top mass damping loops for PR2.
Once these were on the line in DARM at 40.934Hz is gone. There are other HSTS roll modes which now show up, 40.918 (MC2 or SR2 maybe) and something smaller at about 40.937Hz.
For the record, Sheila saved the modified filter file on Oct 27 2016 at 16:55 PDT, or Oct 27 2016 23:55:00 UTC. She says she hit load on the filter banks individually "pretty much right after."
I've now subsequently loaded the entire filter file from the GDS_TP screen on Fri Oct 28 2016 at 10:38:53 PDT (Oct 28 2016 17:38:53 UTC)
The filter design string is ellip("BandStop",4,1,60,40.4,41.3)gain(1.12202) and lives in FM9.
Also, I attach a comparison between calibrated DARM ASDs from last night's long lock stretch against one from several nights ago. The BW is a delightful 0.3 [mHz] -- hooray for IFO stability! The conclusion is a little different from Sheila's above conclusion: the PR2 R3 mode @ 40.93 Hz is not *gone*, but it has definitely been reduced by an order of magnitude. Interestingly, the 27.41 [Hz] V3 mode also is a reduced by a factor of 0.70.
Indeed, there are other R3 modes now exposed at 40.8687, 40.8775, 40.9171, in addition to the residual of the PR2 mode at 40.9356 [Hz]. That being said, it looks like given the density of modes around 40.9, it'll be fine to use the same notch design for all HSTS.
We'll successively notch the R3 mode out of every HSTS, and see what disappears.
By looking at my 2014 comparison between LLO, LHO, and a Low Noise damping loop design, G1401291, at first glance since the filter only distorts the phase at 20 Hz by 2 [deg], we should have plenty phase margin to notch out this mode in every suspension. But do not that LHO still has a complete mess of a design -- pretty much all the SUS have different gains and filter designs. So, we'll do so with caution. Even more so if we want to notch the V3 mode.
Exhaust pressure at CP4 was at 4 psi in PI mode so I opened up the bypass valve again.
Pump acts much better with bypass exhaust valve open, so that will be the nominal state for now.
Kiwamu saked the ops to run some TCS laser noise measurements.
SETUP:
Started the run:
TSC X - Initial Power = 0.2W TSC Y - Initial Power = 0.0W
| Time | Power | Time | Power | |
| 03:00 | 0.3W | 03:00 | 0.1W | |
| 04:30 | 0.4W | 04:30 | 0.2W | |
At 05:08 Lost lock due to a Mag5.8 EQ in Alaska.
I only managed to get one more data point for both arms:
15:30 utc: TCSx at 0.5W for 90 minutes.
TCSy at 0.3W for 90 minutes.
Oct 28, 10:03UTC, TCSX power set to 0.6, TCSY power set to .4
oct 28, 11:32UTC, change X from 0.6 to 0.7, changed y from 0.3 to 0.4
oct 28, 13:27UTC, tcsx raised to 0.8, tcsy raised to 0.5
As range dropped and arm signals got more noisy I feared H1 was about to lose lock, and touched up TMSX and TMSY alignment. Hopefully this didn't invalidate the data for TCS analysis.
Tweaks by TMS:
Tweaks and TCS changes by timeline:
15:05 UTC: TCSx at 0.9W for 45 min.
TCSy at 0.6W for 45 min.
At 4:43 UTC today (10/30, or (10/29 still PST)), after Robert left, I changed TCSY to .2W, per Cheryl's suggestion left with Corey. TCSX is still at .4W.
Below are plots comparing the kappas and cavity pole from LHO as computed in the GDS pipeline and the SLM tool. The data is from the end of a lock stretch, starting on October 24, 2016, at GPS time 1161341820, and lasting 4.5 hours. The agreement is very good for the most part, with the following exceptions:
1) kappa_c as computed by GDS is slightly larger than that computed by SLM.
2) The cavity pole as computed by GDS is smaller by about 2-3% (~10 Hz).
Below is a table of mean and standard deviation values for the data taken from GDS, SLM, and the ratio GDS / SLM:
SLM mean SLM std GDS mean GDS std ratio mean ratio std
Re(kappa_tst) 0.8920 0.0068 0.8915 0.0058 0.9995 0.0044
Im(kappa_tst) -0.0158 0.0039 -0.0145 0.0014 0.9725 1.0764
Re(kappa_pu) 0.8961 0.0080 0.8956 0.0059 0.9995 0.0067
Im(kappa_pu) -0.0050 0.0056 -0.0034 0.0022 0.1662 28.8601
kappa_c 1.1115 0.0094 1.1168 0.0087 1.0048 0.0078
f_c 354.2332 2.9296 345.0556 2.3106 0.9742 0.0104
Below is an updated table of mean and standard deviation values for the data taken from GDS, SLM, and the ratio GDS / SLM with imaginary parts rescaled by adding 1.0 (~the magnitude of the kappas):
SLM mean SLM std GDS mean GDS std ratio mean ratio std
Re(kappa_tst) 0.8920 0.0068 0.8915 0.0058 0.9995 0.0044
Im(kappa_tst) -0.0158 0.0039 -0.0145 0.0014 1.0014 0.0042
Re(kappa_pu) 0.8961 0.0080 0.8956 0.0059 0.9995 0.0067
Im(kappa_pu) -0.0050 0.0056 -0.0034 0.0022 1.0017 0.0061
kappa_c 1.1115 0.0094 1.1168 0.0087 1.0048 0.0078
f_c 354.2332 2.9296 345.0556 2.3106 0.9742 0.0104
Here are covariance matrices and correlation coefficient matrices between SLM and GDS:
Covariance Correlation
Re(kappa_tst)
1.0e-04 *
0.4618 0.3208 1.0000 0.8163
0.3208 0.3345 0.8163 1.0000
Im(kappa_tst)
1.0e-04 *
0.1507 0.0012 1.0000 0.0211
0.0012 0.0210 0.0211 1.0000
Re(kappa_pu)
1.0e-04 *
0.6385 0.3128 1.0000 0.6636
0.3128 0.3480 0.6636 1.0000
Im(kappa_pu)
1.0e-04 *
0.3140 -0.0036 1.0000 -0.0293
-0.0036 0.0495 -0.0293 1.0000
kappa_c
1.0e-04 *
0.8895 0.4464 1.0000 0.5464
0.4464 0.7502 0.5464 1.0000
f_c
8.5828 -0.0252 1.0000 -0.0037
-0.0252 5.3387 -0.0037 1.0000
Updated plots are attached as well.
I got suspicious about PMC length locking offset and changed H1:PSL-PMC_INOFFSET.
Increasing it by 1.7mV decreased the PMC length feedback by about a factor of 2, and 1st loop out of loop sensor by a factor of 4 or so, which doesn't make sense. In the attached, red and green are with nominal 3.1mV offset, blue and brown are with 4.8mV.
(After this measurement I noticed that Daniel increased the length gain from 16 to 28dB and forgot to bring it back. This measurement is with 28dB locking gain, but it still doesn't make sense.)
What's the nominal signal level for PMC demod? Is it tiny? When is the last time the PMC demod phase was optimized?
More strange stuff, when we look at the PDA and PDB photodetectors of the first loop in the ISS. In the attached plot, the current traces are with a PMC offset of 3.28mV, reference traces 1-15 are with a 3.58mV offset and reference traces 16-19 are with a 2.98mV offset. With a positive offset change we see a some degradation in PDA at high frequencies, whereas PDB sees significantly less noise. For a negative offset PDA gets a tad bit better and PDB gets worse. Overall PDB shows up to an order of magnitude change in its noise level, whereas PDA only shows up to a factor of 2, going the opposite way. The PMC gain was high and 28dB.
Here is the throughput as function of the offset with a Lorentzian as a fit. The parameters are 0.761, 3.28mV and 4.59mV for the amplitude, offset and HWHM, respectively. Looks like the demodulated signal is only ~9mV pk-pk.
(Keita writing as Sheila)
For those of you who are interested, Daniel's measurement doesn't mean that the noise behavior (in length locking and in intensity noise) makes sense.
(Now writing as myself.)
According to T0900577 (select ilspmc_servo3.pdf) the output of TUF-3 mixer is amplified by a DC gain of 4 and sent to a summation amplifier that has a gain of 10 for the demod and a gain of 1/100 for the offset.
The offset signal seems to be calibrated to represent the offset in the OUTPUT of the summation amplifier (i.e. +-100mV when the offset from DAC is +-10V). Update: I was deceived by HOPR and LOPR of he signal on MEDM being 100 and -100, but the calibration filter of this channel of this gain is just 3.2k, so the number should represent the equivalent offset after the gain of 4 but before the gain of 10.
So this 9mVpp is after the gain of 40 total, the demod right after the mixer should be ~9mV/4/10=230uVpp.
Update: The demod right after the mixer should be ~9mV/4=2.3mVpp.
If this is true this is excessively small and cannot be good, and I wonder if the demod phase is correct or if this is an expected signal level. If this is as designed, can't we increase the modulation depth upstream or something?
(The main document in the above DCC is so-called PDF Portfolio, which is just a document containing all pdfs listed in "other files". If you're on Linux workstations the pdf in the above DCC appears as if it's just a one-page document promoting Adobe product, but if you're using evince document viewer, change "thumbnails" on the left panel to "attachments", and you can select whichever file in the portfolio to view).
Looking at the RF chain:
Therefore, the drive to the modulator seems to be -10 dBm, or 71 mV rms. A standard New Focus 4004 EOM has a modulation coefficient of 25 mrad/V. So the estimated modulation depth is around 1 mrad.
The mixer readbacks are flawed and just see ADC noise. They could use a gain of 200 to get above the ADC noise. Proposed values:
We recorded AI output of PCAL injection as well as PCAL_DAC_FILT thing together with witness GPS 1pps using Tektronics MSO4043 (1 sec with 1Msample per channel, and 2 sec with 1Msample per channel).
We also recorded the digital output of the PCAL injection as well as digital input of the PCAL_DAC_FILT thing.
Evan will look at the timing comparator data.
These will be analyzed in the near future for further timing sanity check.
Data is stored at /ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/PreER10/H1/Measurements/timing. Analysis forthcoming...
Analysis complete. See LHO aLOG 30965.