I reported the WD plotting issue mentioned by hugh last week. Details can be found in LHO aLog #10057

I am not sure what is going on yet, scripting or server access issue, but I am looking into it.

The plotting scripts work for the HAM-ISI. WD plotting is still disfunctional on the BSC. I think it is a scripting issue in that case, and I am working towards fixing it:

The BSC-ISI WD plotting software was fixed, see LHO aLog #10258 for more details.

PRMI locks:

Today I was able to lock the PRMI with the sidebands resonant in the PRC. There were three key points:(1) the alignment was not great, (2) the notches in FM6 of MICH (see alog 10127) was too aggressive for the initial acquisition and (3) a 30 Hz low pass was not engaged in MICH's FM9 which was usually set up by the guardian.

My first guess for the MICH and PRCL gains were 40 and -0.4 respectively (see alog 10168) because these are the nominal values we have been using in the past week. However, it turned out that the alignment of PRMI was not good enough so that optical gain was smaller by a factor of between 2 and 3 for both MICH and PRCL. So I empirically ended up with gain settings of 80 and -1.4 for MICH and PRCL respectively to acquire a lock for a long period. Then tweaking PRM and PR2 gave me a high build up which was approximately 30000 counts in POPAIR_B_RF18 and this is about the same amount we saw on 11th of February. The attached is a trend of the power build up and alignment sliders. The misalignment was mainly in pitch.

At the end, the gain was at 40 and -0.6 in MICH and PRCL respectively. I didn't get a chance to measure the UGF.

Next steps:

Our short term goal is to do the "one arm + PRMI 3f" test and therefore the stability study of the 3f locking is the most critical at this moment. However I (re-)found that the daily alignment is time-consuming and is something we must automate. So I would like to get the dither system running at first before entering a serious 3f study.

Even though the PRMI didn't spontaneously drop the lock at the end of the morning commissioning, fluctuation in the intracavity power was large. The power could drop to the half of its maximum and was oscillating mainly at 0.9 Hz. Looking at the PR3 gigE camera (VID-CAM09), I found that the oscillation of the cavity power synchronized with scattered light off of the PR3 cage which looked oscillating mainly in pitch. So I tried to identify which optic was moving by using the data from this morning.

According to a coherency test (see the attachment), ITMY is the most suspicious at this point.

ITMY was oscillating at 0.4-ish Hz and shows a moderately high coherence with the POP_B_RF18. It is possible that this 0.4-ish Hz motion of ITMY then produced a fluctuation in POP_RF18 at the twice higher frequency due to the quadratic response of the cavity power. This issue is not a killer at this point, but the study will continue.

ETMX is now realigned for the blue team. Oplev is still off.

After the recent upgrade, where I rebuilt the node supervision infrastructure on h1guardian0, I did not yet get around to re-creating and restarting all of the nodes that had been running previously.  Arnaud and I are now restarting all the SUS nodes, but just in case, this should be an easy issue to resolve:

The guardctrl utility will tell you which nodes are currently running:

jameson.rollins@operator1:~ 0$ guardctrl list
IFO_IMC * run: IFO_IMC: (pid 11768) 144328s, want down; run: log: (pid 26686) 145415s
ISI_HAM4 * run: ISI_HAM4: (pid 26143) 3148s, want down; run: log: (pid 11352) 53329s
LSC * run: LSC: (pid 20593) 48884s, want down; run: log: (pid 11727) 48972s
SUS_ETMX * down: SUS_ETMX: 145415s; run: log: (pid 26687) 145415s
SUS_MC1 * run: SUS_MC1: (pid 29305) 145317s, want down; run: log: (pid 26685) 145415s
SUS_MC2 * run: SUS_MC2: (pid 29314) 145317s, want down; run: log: (pid 26863) 145413s
SUS_MC3 * run: SUS_MC3: (pid 29327) 145317s, want down; run: log: (pid 26864) 145413s
SUS_SRM * run: SUS_SRM: (pid 1869) 63862s, normally down, want down; run: log: (pid 1027) 150829s
jameson.rollins@operator1:~ 0$ 

Any node you think should be there but is not showing up, you can just create:

jameson.rollins@operator1:~ 0$ guardctrl create SUS_PRM
creating node SUS_PRM...
adding node SUS_PRM...
guardian node created:
ifo: H1
name: SUS_PRM
path: /opt/rtcds/userapps/release/sus/common/guardian/SUS_PRM.py
prefix: SUS-PRM
usercode:
  /opt/rtcds/userapps/release/sus/common/guardian/sustools.py
  /opt/rtcds/userapps/release/sus/common/guardian/SUS.py
states (*=requestable):
  0 MISALIGNED *
  1 SAFE *
  2 DAMPED *
  3 ALIGNED *
  4 INIT
  5 TRIPPED
jameson.rollins@operator1:~ 0$

Once the node is created, it is ready to start.  Before starting, I usually pop open a window viewing the log from the node so I can watch the start up.  This is most easily done by opening up the medm control panel for the node via the GUARD_OVERVIEW screen, and clicking on the "log" link.

Finally, just start the node:

jameson.rollins@operator1:~ 0$ guardctrl start SUS_PRM
starting node SUS_PRM...
jameson.rollins@operator1:~ 0$ 

We're working on making all the guardians smart enough to identify the current state of the system on startup, and identify the correct state to jump to.  The SUS guardians are programmed to go to the ALIGNED state on startup.  We're now working on enabling them to identify if the optic is currently misaligned and to go to the MISALIGNED state in that case.

During the afternoon, the locking of Green PDH was quite unstable. We suspected that there were some oscillations of the NPRO PZT and/or accidental HOM resonances (since the mode-matching / clipping is so bad).

* Sweeping the NPRO PZT with a low bandwidth PLL lock, found no substantial features in the neighborhood of the peak (~27.4 kHz). Even though there's no resonances in the TF, the peak dominates the RMS of the PDH error signal. We thought that this could perhaps be coming from an oscillation of the PSL FSS, but tweaking the FSS Fast gain doesn't change the peak frequency.

* We tried a few different modulation frequencies for PDH (23.4, 23.9, and 24.4 MHz). These were calculated to make the upper SB be at ~0.3-0.4 of an FSR. As expected we saw a big dip in the PDH loop in the 10-15 kHz range for these different modulation frequencies. These dips were not very stationary - we guessed that this was due to the alignment fluctuations.

* Daniel turned on the 1000:100 Boost in the servo board after awhile and this greatly helped the stability. At the best of times, the green arm power fluctuations were ~10%. At the worst of times, it was more like 50% and the mode would hop between 00 and 01. We had mixed results with the dither alignment and its not always working for both DOFs.

* We should use a directional coupler to check that we're at the peak frequency for the EOM.

Some observations: After reverting to the original sideband frequency we had a hard time locking. The behaviour was similar to what we experienced in the past when we had a lot of alignment fluctuations. We would stay "locked' but switch between 00 mode and a higher order transverse mode without loosing a step. In the past the transition was to a 10 mode whereas yesterday it was to a second order mode. The locking was better when we switched back again to the frequency that is 1MHz off. It turned out that the sidebands were coincidentally set near the second order transverse mode spacing. Using a frequency near nominal with the same tuning worked as well. However, it turned out the real problem was a lack of low frequency gain. With the standard network compensation we just have a pole near 1.6Hz, With the boost turned on the lock is a lot more stable. This seems especially important during elevated wind.

Changing the AA chassis didn't fix the problem. So, it is probably the ADC. To minimize the disruption we simple switched to a different channel for now.

MEDM updates completed.

BTW: the new model added one Shared Memory IPC channel on the h1oaf0 frontend:

In the latest oaf model, I intentionally deleted the IPC blocks for now which were supposed to receive signals from HEPIs and ISIs. In any case, the original motivation of starting the OAF model was to get the IMC signal received and saved as science frames, and this was achieved by this installation. At some point in the future, we should revisit the model and implement the IPC blocks back, which requires changes in some other models (see the detail in alog 9963).

Written by Yuta

I found that I forgot to put 0.05 in my OLTF model (I forgot that the output matrix H1:LSC-OUTPUT_MTRX for MICH to BS was set to 0.05). I also forgot to put sqrt(2) to convert BS motion to MICH length change. I updated the OLTF figure, and now, the missing factor is 0.024.

Written by Yuta

The missing factor 0.024 was from the conversion factor in uN/counts.
I assumed that the suspension model I use gives me the transfer function in m/counts, but it was actually in m/uN.
The conversion factor can be calculated using the parameters in G1100968 (for BS specific, see T1100479);

0.963 N/A * 0.32 mA/V * 20.0/2**18 V/counts = 2.35e-8 N/counts = 0.024 uN/counts

The OLTF now agrees well with the expected. Thanks to Jeff K. and Arnaud!
(But still, there is a missing factor in the PD signal chain. The measured value 7.6 counts/nm is used in this expected curve. See alog #9630 and #9857)

Note that this factor(uN/counts) is also missing in the current noise budget model which lives in /ligo/svncommon/NbSVN/aligonoisebudget/trunk/PRMI.