Related: https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=14567

Summary:

We're still close to the East edge of the PR2 baffle, it may be better to go further to the left for safety but we won't gain much as far as the power recycling gain goes.

The centering on PR2 is off by a centimeter-ish (or the baffle is offset from PR2 or the baffle is smaller than it should be).

The beam seems to be somewhat larger than it should be.

There is some clipping downstream of PR2 so we need more scans to find where that is.

In the right plot,  blue circle is the PR2 baffle looked down from the PR2, green circles are the IFO beam ideally located, red cross is the PRM-PR2 beam position calculated from the slider, and the red circle is the beam position calculated from the fit.

Note that red cross and red circle have +-14%-ish error bar (both position and the size), but it seems like the beam is bigger and the beam closer to the East edge than it should be.

The left plot is the same as the one in the above mentioned alog, but replotted such that the X axis was rescaled as the beam distance from the East edge of the baffle using the new calibration of the IM4 slider (explained later). This X axis itself has +-14%-ish error bar.

The curve is the fit of POP_A and POP_B combined for the left half of the plot, assuming that the baffle transmission is approximated by a beam clipped by a vertical edge. Beam radius, edge position and the overall scale were the three fitting parameters (the overall scale is necessary because we don't know if the maximum transmission corresponds to zero loss).

Green vertical line is where we were at this morning, blue is where we used to be last Tuesday.

It would appear as if we should go further to the right on the plot, but clearly there is some kind of clipping on the sled path in that direction. As far as there's no clipping in the POP_AIR path that is OK, that's yet to be seen.

Removed power to EX tiltmeter for a few minutes to dress power cable inside rack. Work was done around 9:50 AM this morning.

Jim, Dave, Hugo

at 08:03PDT Sunday Morning, 26th Oct 2014 the h1iopseih45 dac-enable was unset (8th bit of h1iopseih45 STATE_WORD). From this point onwards until the h1iopseih45 was restarted this morning no DAC drives were being sent out of this front end. This is presumably a DAC FIFO error, similar to previous such events. We are seeing them roughly once a month.

Frequency of DAC lock out events (requiring IOP model restart to fix). One more event added since my last  entryhttps://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=13930

10/26 2014 h1seih45

9/11 2014 h1seih45

9/10 2014 h1seih23

8/11 2014 h1susb123

8/9 2014 h1seih23

4/21 2014 h1sush2a

3/18 2014 h1sush2a

2/27 2014 h1seih23

12/16 2013 h1seih23

11/7 2013 h1sush2a

11/7 2013 h2sush34

8/8 2013 h1seih23

Jameson, Hugo, Hugh

Debugging the guardian, Jameson suddenly saw the guardian manage to Isolate HAM2 ISI.  But then it wouldn't..  We changed the guardian to behave closer to the command script in that it Isolates RX & RY first and then Isolates the remaining dofs second.  Now maybe that makes a difference but we've come to the conclusion that something (loops?) must be marginal.  With limited data. maybe 4 out of 5 attempts are now isolating with guardian.  If it seems to not isolate with guardian first couple times, let's just damp the ISI for a few moments before going to Isolated.

In an effort to move ahead, we corrected the matrices too and we have it under guardian control.  It has isolated again with about the same robustness (4/5.)

Further, we were going to try the new controllers but the commissioners asked for the IFO while I was running the Prepare Script which loads all the new filters into the foton file.  So HAM2 is ready to Load New Filters.  We will do this tomorrow morning now.

PSL ISS REFSIGNAL adjusted to -2.09V, bringing the Diffracted Power ~7.5%.

model restarts logged for Sun 26/Oct/2014
2014_10_26 14:33 h1fw1
2014_10_26 21:43 h1fw0

both unexpected restarts

Rana and I went out to look at the breakout board for setting the gains/whitening for PR3. We found three out of the four segments were set to have one stage of whitening; the fourth had no whitening. Regardless, all four segments had an antiwhitening filter engaged in their filter banks.

We flipped bits on the breakout board as follows: on each segment, bits 2, 3, and 5 are high; all others are low. This gives one stage of whitening, and somewhere between 5000–10000 dc counts on each segment.

JimW HugoP, (Friday Oct 24th)

Fabrice recently pointed out that ETMY-ISI was not performing as well as the other LHO BSC-ISIs.

Jim adjusted his LV3 contollers and we tried them on Friday. Only the Y controller was changed. We looked at the logitudinal motion on ST1 of the ISI, and at the Pitch and Yaw motion seen by the (re-calibrated) oplev. We compared the ASDs, and RMS motions, before and after the adjutments.

Attached plots tend to indicate that Jim's controller adjustement helped reducing the ETMY logitudinal RMS motion. The new controllers were left ON on Friday.

Found that the DRMI was misaligned this afternoon. Trends show that the HAM5 optics moved and started shaking a little around 8 AM.

I'm able to get the ISI into damped mode, but it trips its vertical actuators if I try to transition into any of the 3 isolation modes via its guardian screens.

Similar situation for HAM5-HEPI. It also trips its vertical actuators (but for this one, the 'plot ACT Trip' button fails to produce a plot; it has some NDS or channel name problems in the script).

We are trying to track down what optics have moved, but this is hampered somewhat by the lack of a SUS DRIFT screen here at LHO.

Having this running would make it easier to find what optic has moved when we have these mysterious misalignments.

model restarts logged for Sat 25/Oct/2014
2014_10_25 07:26 h1fw1
2014_10_25 18:42 h1fw0

both unexpected restarts

After the whitening gain tune up for the BS OL QPD this week, we tried using the OL damping, but found that the performance was underwhelming.

Using the HSTS BS SS model from the SUS group in the noise budget directory, I made some filters to give us gain in the 0.1-3 Hz band and some low pass filtering above 10 Hz. Also some notches for the bounce/roll modes, but since I couldn't find the measured frequencies, I just copied from LLO.

The attached Bode plot shows the modeled pitch and yaw loop shapes. The yaw one is a little less stable due to the different yaw eigenfrequencies - I just used simple poles/zeros rather than try plant inversion. Rather than fine tune the OL loops we'd be better off tweaking the BOSEM damping loop for yaw to reduce the 2.1 Hz Q. I also chose to have the lower UGF be above 0.1 Hz to prevent too much interaction with the slow WFS loops. The 0.2 Hz bump in the yaw loop is an optional 'MSboost' filter that I've added to squash a 0.15-0.25 Hz microseismic peak. I would leave it on all the time, but we could have a few of these for different microseismic states. The 4th attachment shows the step and impulses of the loops with MSboost ON. The top left plot shows the step response of the pitch loop. The bottom left the step response of the yaw loop. The plots on the right show the responses of the pitch and yaw loops to step and impulse applied to the M2_L DoF. The impulse amplitude is sized to be close to what the lock acquisition transient is in force, but probably too long in duration.

I will show the before and after spectra, but the winds started audibly shaking the control room an hour ago, making it kind of an unfair comparison.  The 0.1-1 Hz ground noise has not changed much, but the 2-30 Hz noise is up by a factor of ~10.

A piece of good news: the broadband noise seen earlier this week in the yaw error signal is gone. The broadband noise in both pitch and yaw is now 1e-10 rad/rHz above 2 Hz. The huge peak at 20 Hz in the pitch spectrum is probably the flagpole mode of the cerulean pillar.

For all OL, we should add the OL feedback signals (OLDAMP_{P/Y}_OUT)to the DAQ and remove the OLDAMP_IN2 channels (not needed since we already record M3_OPLEV_OUT). 

These will be 256 Hz channels, so impact on frame size is minimal.

After our modifications to the DRMI LSC thresholds and loop gains on Thursday night, we had several short locks. Yesterday, we saw the same good locking behavior again. We found that the reason for the short lock duration was a typo in our trigger matrix: the PRCL boosts weren't getting turned on. After switching those and tweaking some filter shapes, the locking is fast and the locks last a long time.

The first attached plot shows the minute trend of our 4 hour lock last night. The 6 WFS loops are engaged during this time, as well as the DC centering. Near the end of the lock, there is a SRC mode hop and it stays locked like that for 1 hour. There are 20% fluctuations in the SPOP18 and SASY90. The control signal plots in the left hand column are scaled so that the full y-scale is approximately the full suspension DAC range (there is a divide by 4 from the LSC to the SUS DAC outputs). The MICH and PRCL loops are pretty calm, but there are several large transients in the SRCL loop which, I believe, corresponds to the TEM00 -> TEM01/10 mode hop.

The second PDF shows the error and control signal spectra for the DRMI LSC loops during a non-hopping epoch from last night.

PRCL: The error signal is white, so not much to be gained by changing the loop shape. The control signal is dominated by 0.05 - 0.5 Hz as is expected from the ISI performance.

MICH: The error signal is dominated by sub-Hz stuff, so we could squash it better with a 1:0.1 zero:pole stage if we found it necessary. The MICH control signal is dominated more by the sub 0.1 Hz motion than anythin else in the DRMI.  Usually we think this is the seismic amplification produced by the seismic isolation system.

SRCL: Similar story to PRCL, but more noise from <0.1 Hz than 0.1-0.5 Hz.

In all spectra, the large line at 131 Hz is a calibration line used for making sensing matrix and demod phase measurements.

After the lock loss, it never got it itself together. The ASC loops stayed railed and kept it from being aligned enough to lock. 
Also, the Guardian had a filter writing problem and so it stopped restoring the correct IFO state after the DOWN state 
(it was trying to set a filter which was under the control of the LSC filter module trigger logic and stopped because it didn't 
get the correct readback. This fault condition should be added to Guardian to make the log file more informative and we 
should fix this conflict in the LSC state defs). 
After clearing all of that stuff and bypassing the Guardian temporarily, the Michelson, PRMI and DRMI all locked fine.