 Mon Mar 15 20:22:01 2021, gautam, Update, ASC, c1rfm model restarted 
|
On Friday, I felt that the ASC performance when the PRFPMI was locked was not as good as it used to be, so I looked into the situation a bit more. As
part of my ASC model revamp in December, I made a bunch of changes to the signal routing, and my suspicion was that the control signals weren't even
reaching the ETMs. My log says that I recompiled and reinstalled the c1rfm model (used to pipe the ASC control signals to the ETMs), and indeed, the file |
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Fri Mar 12 21:15:19 2021, gautam, Update, LSC, coronaversary PRFPMi
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Attachment #1 - proof that the lock
is RF only (A paths are ALS, B paths are RF).
Attachment #2 - CARM OLTF. |
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Fri Mar 12 19:44:31 2021, gautam, Update, LSC, Delay line
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I may want to use the delay line phase shifter in 1Y2 to allow remote actuation of the REFL11 demod phase (for the AO path, not the low bandwidth one).
I had this working last Feb, but today, I am unable to remotely change the delay. @Koji, it would be great if you could
fix this the next time you are in the lab - I bet it's a busted latch IC or some such thing. I did the non-invasive tests - cable is |
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Fri Mar 12 18:10:01 2021, Anchal, Summary, Computer Scripts / Programs, Installed cds-workstation on allegra
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allegra had fresh Debian 10 installed on it already. I installed cds-workstation packages (with the help of Erik von Reis). I checked that command line
caget, caput etc were working. I'll see if medm and other things are working next time we visit the lab. |
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Fri Mar 12 11:44:53 2021, Paco, Anchal, Update, training, IMC SUS diagonalization in progress
|
[Paco, Anchal]
- Today we spent the morning shift debugging SUS input matrix diagonalization. MC stayed locked for most of the 4 hours we were here, and we
didn't really touch any controls. |
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Thu Mar 11 14:27:56 2021, gautam, Update, CDS, timesync issue?
|
I have recently been running into hitting the 4MB/s data rate limit on testpoints - basically, I can't run DTT TF and spectrum measurements that
I was able to while locking the interferometer, which I certainly was able to this time last year. AFAIK, the major modification made was the addition
of 4 DQ channels for the in-air BHD experiment - assuming the data is transmitted as double precision numbers, i estimate the additional load due to this |
 Thu Mar 11 18:46:06 2021, gautam, Update, CDS, cds reboot
|
Since Koji was in the lab I decided to bite the bullet and do the reboot. I've modified the reboot script - now, it prompts the user to confirm that
the time recognized by the FEs are the same (use the IOP model's status screen, the GPSTIME is updated live on the upper right hand corner).
So you would do sudo date --set="Thu 11 Mar 2021 |
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Fri Mar 12 03:28:51 2021, Koji, Update, CDS, cds reboot
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I want to emphasize the followings:
FB's RTC (real-time clock/motherboard clock) is synchronized to NTP time.
The other RT machines are not synchronized to
NTP time.
My speculation is that the RT machine timestamp is produced from |
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Fri Mar 12 11:02:38 2021, gautam, Update, CDS, cds reboot
|
I looked into this a bit today morning. I forgot exactly what time we restarted the machines, but looking at the timesyncd logs, it appears that the
NTP synchronization is in fact working (log below is for c1sus, similar on other FEs):
-- |
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Fri Mar 12 03:23:37 2021, Koji, Update, BHD, DO card (DO-32L-PE) brought from WB
|
| I've brought 4 DO-32L-PE cards from WB for BHD upgrade for Jon. |
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Fri Mar 12 03:22:45 2021, Koji, Update, General, Gaussmeter in the electronics drawer
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For magnet strength measurement: There is a gaussmeter in the flukes' drawer (2nd from the top). It turns on and reacts to a whiteboard
magnet. |
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Thu Mar 11 20:18:00 2021, gautam, Update, LSC, High bandwidth POY
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I repeated the high bandwidth POY locking experiment.
The "Q" demod output (SMA) was routed to the common mode board (it appears in the past I used the LEMO "MON"
output instead but that shouldn't be a meaningful change).
As usual, slow actuation --> ETMY, fast actuation --> IMC error point.
Loop |
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Thu Mar 11 14:03:02 2021, gautam, Update, LSC, AO path
|
There is some evidence of weird saturation but the gain balancing (0.8dB) and orthogonality (~89 deg) for the daughter board on the REFL11 demod board
that generates the AO path error signal seem reasonable. This board would probably benefit from the AD797-->Op27 and thick-film-->thin film swap
but i don't think this is to blame for being unable to execute the RF transition. |
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Thu Mar 11 02:10:06 2021, Koji, Summary, BHD, BHD Platform vertical dimentions
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Stephen and I discussed the nominal heights of the BHD platform components.
The beam height from the stack is 5.5"
The platform height is 1.5" and the thickness of 0.4", according to
the VOPO suspension, which we want to be compatible with.
Thus the beam height on the BHD platform is 4".
The VOPO platform |
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Wed Mar 10 00:32:03 2021, gautam, Update, LSC, PRFPMi
|
The interferometer can nearly be locked again. I was unable
to fully hand off control from ALS-->RF, I suspect I may be using the wrong sign on the AO path (or some such other sub-optimal CM board settings).
I'll hook up the SR785 and take some TFs tomorrow, that should give more insight into what's what. With the arms held off resonance, the PRMI acquires |
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Thu Mar 11 01:45:42 2021, gautam, Update, LSC, PRFPMi
|
PRM satellite box indeed seems to have been the culprit - shortly after I swapped it to the SRM, its shadow sensors went dark. I leave the watchdog
tripped.
I still was unable to realize the RF only IFO
Clearly my old settings don't work, so I tried to go about it systematically.
First, try and transition CARM to RF, leave DARM on ALS.
As usual, I can realize the state were the arm powers are ~100, and the two paths |
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Wed Mar 10 19:58:27 2021, gautam, Update, LSC, SR785 hooked up to CM board
|
| In preparation for later today evening. The TT alignment wasn't visibly disturbed. |
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Wed Mar 10 11:55:22 2021, gautam, Update, SUS, PRM suspension suspect
|
The procedure is that the optic is kicked to excite it, and allowed to ring down for ~1ksec, with damping turned off. The procedure is repeated 15 times
for some averaging.
Attachment #1 - sensor spectra |
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Wed Mar 10 17:35:47 2021, gautam, Update, SUS, Spooky action at a distance
|
As I am sitting in the control room, the PRM suspension watchdog tripped again. This time, there is clearly no seismic activity. Yet,
the BS suspension also shows a slight disturbance at the same time as the PRM. ITMY shows no perturbation though. My best hypothesis here is that
the problem is electrical. In Attachment #1, |
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Thu Feb 18 15:15:12 2021, yehonathan, Update, SUS, OSEM testing for SOSs
|
I am setting up a testing rig for the OSEMs we recently obtained. I found the schematic
for the OSEM assembly from which the pin assignment can be read.
I connected the OSEM's pin plate to a female DB15 on a breakout board. I find the pin assignment (attachment 1, sorry for the image quality) |
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Mon Feb 22 14:06:49 2021, Yehonathan, Update, SUS, OSEM testing for SOSs
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Continuing with the OSEM testing. I measure the resistance of the wires from the RLC meter to the coil to be ~ 0.9ohm. I will subtract this number from
the subsequent coil resistance measurements.
I took the old MC1 satellite box for powering the PD and LED in the OSEM assemblies. I connected an idc breakout board to J4 and powered the |
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Wed Feb 24 10:23:03 2021, Yehonathan, Update, SUS, OSEM testing for SOSs
|
Continuing with the new rig, I measure the resistance of the cable leading to the coil to be 0.08+(0.52-0.08)+(0.48-0.08)=0.9ohm.
S/N
Coil Resistance |
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Wed Mar 3 11:51:07 2021, Yehonathan, Update, SUS, OSEM testing for SOSs
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I finished testing the OSEMs. I put all the OSEMs back in the box. The OSEMS were divided into several bags. I put the OSEM box next to the south flow
bench on the floor.
I have uploaded the OSEM catalog to the wiki. I will upload the LED spot images later. |
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Tue Mar 9 14:30:22 2021, Yehonathan, Update, SUS, OSEM testing for SOSs
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I finished ranking the OSEMS on the OSEM wiki page.
I also moved the OSEM data folder from /home/export/home to /users/public_html and created a soft link instead. I have done the same for the
40m_TIS folder that I uploaded there a while ago. |
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Tue Mar 9 15:19:03 2021, Koji, Update, SUS, OSEM testing for SOSs
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| How were the statistics of them? i.e. # of Good OSEMs, # of OK OSEMs, etc... |
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Tue Mar 9 18:49:28 2021, Yehonathan, Update, SUS, OSEM testing for SOSs
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29 Good OSEMs, of which 1 is questionable (089) with PD voltage of 1.5V, 5 need some work (pigtailing, replace/remove/add screws). We have 4 pigtails.
Schematics.
20 OK OSEMs (Slightly off-centered LED spot), of which 3 need some work (pigtailing, replace/remove/add screws). |
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Tue Feb 23 20:55:19 2021, Koji, Update, SUS, OSEM testing for SOSs
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I can't obtain a consistent view between the existing drawings/photographs and your pin assignment. Please review the pin assignment again to check
if yours is correct.
|
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Wed Feb 24 10:09:16 2021, yehonathan, Update, SUS, OSEM testing for SOSs
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Yes, my phone camera mirrored the image. Sorry for the confusion.
I see you already uploaded the correct pin assignment.
Quote:
|
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Tue Mar 9 10:57:06 2021, Paco, Anchal, Summary, IMC, XARM lock and POX spectra
|
[Paco, Anchal]
- Upon arrival, MC is locked, and we can see light in MON5 (PRM) (usually dark).
# XARM locking |
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Tue Mar 9 14:37:26 2021, gautam, Summary, SUS, PRM suspension
|
The PRM got tripped ~5AM this morning. The cause is unclear - the seismometer reports elevated activity ~10 minutes before the ringdown starts (as judged
using the OSEMs). But the other optics didn't seem to receive as much of an impulse (I only show the BS sensors here as it sits on the same stack as
the PRM). Anyway it certainly wasn't me trying to make life difficult for the morning team. |
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Tue Mar 9 15:22:56 2021, Koji, Summary, SUS, PRM suspension
|
I just saw the PRM watchdog tripped at ~15:20 local (23:20UTC). I restored the PRM but I saw only the side watchdog tripped.
Again at 15:27
17:55 I found the PRM was oscillating while the watchdogs were not tripped. I turned off the OPLEV servos and this made the PRM calmed down. |
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Tue Mar 9 12:41:29 2021, Koji, Summary, Electronics, Investigation on the invacuum Dsub cables
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I believe the aLIGO style invac dsub cables and the conventional 40m ones are incompatible.
While the aLIGO spec is that Pin1 (in-vac) is connected to the shield, Pin13 (in-vac) is the one for the conventional cable. I still have to
check if Pin13 is really connected to the shield, but we had trouble before for the IO TTs https://nodus.ligo.caltech.edu:8081/40m/7864. |
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Sun Mar 7 15:26:10 2021, gautam, Update, LSC, Housekeeping + more PRMI
|
Beam pointing into PMC was tweaked to improve transmission.
AS110 photodiode was re-installed on the AS table - I picked off 30% of
the light going to the AS WFS using a beamsplitter and put it on the AS110 photodiode.
Adjusted ASDC whitening gain - we have been running nominally
with +18dB, but after Sept 2020 vent, there is ~x3 amount of light incident on the AS55 RFPD (from which the ASDC signal is derived). I want to run the |
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Mon Mar 8 22:01:26 2021, gautam, Update, LSC, More PRMI
|
There are still many mysteries remaining - e.g. the MICH-->PRCL contribution still can't be nulled. But for now, I have the settings that keep
the PRMI locked fairly robustly with REFL55I/Q or REFL165I/Q (I quadrature for PRCL, Q for MICH in both cases), see Attachment #1 and Attachment |
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Mon Mar 8 20:11:51 2021, rana, Frogs, Computer Scripts / Programs, activate_matlab out of control on Megatron
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there were a zillion processes trying to activate (this is the initial activation after the initial installation) matlab 2015b on megatron, so I killed
them all. Was someone logged in to megatron and trying to run matlab sometime in 2020? If so, speak now, or I will send the out-of-control process
brute squad after you! |
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Mon Mar 8 17:09:29 2021, gautam, Update, SUS, PRM coil actuators heavily imbalanced
|
I realized I hadn't checked the PRM actuator as thoroughly as I had the others. I used the Oplev as a sensor to check the coil balancing, and I noticed
that while all 4 coils show up with the expected 1/f^2 profile at the Oplev error point, the actuator gains seem imbalanced by a factor of ~5. The phase
isn't flat because of some filters in the Oplev electronics I guess. The Oplev loops were disabled for the measurement, and the excitations were small |
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Mon Mar 8 12:54:54 2021, gautam, Update, Equipment loan, 40m-->Cryo
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Busby box
SR554 transformer preamplifier
|
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Sat Mar 6 12:34:18 2021, gautam, Update, LSC, Sensing matrix settings messed with
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To my dismay, I found today that somebody had changed the oscillator frequencies for the sensing matrix infrastructure we have. The change happened 2
days and 2 hours ago (I write this at ~1230 on Saturday, 3/6), i.e. ~1030am on Thursday. According to the elog, this is when Anchal and Paco were working
on the interferometer, but I can find no mention of these settings being changed. Not cool guys 😒 . |
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Sun Mar 7 19:56:27 2021, Anchal, Update, LSC, Sensing matrix settings messed with
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I understand this mst be frustrating for you. But we did not change these settings, knowingly atleast. We have documented all the things we did there.
The only thing I can think of which could possibly change any of those channels are the scripts that we ran that are mentioned and the burt restore that
we did on all channels (which wasn't really necessary). We promise to be more vigilant of changes that occur when we are present in future. |
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Tue Mar 2 19:52:46 2021, gautam, Update, LSC, REFL55 demod board rework
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There were multiple problems with the REFL55 demod board. I fixed them and re-installed the board. The TFs and noise measured on the bench now look more
like what is expected from a noise model. The noise in-situ also looked good. After this work, my settings for the PRMI sideband lock don't work anymore
so I probably have to tweak things a bit, will look into it tomorrow. |
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Wed Mar 3 22:13:05 2021, gautam, Update, LSC, REFL55 demod board rework
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After this work, I measured that the orthogonality was poor. I confirmed on the bench that the PQW-2-90
was busted, pin 2 (0 degree output) showed a sensible signal half of the input, but pin 6 had far too small an output and the phase difference was more
like 45 degrees and not 90 degrees. I can't find any spares of this part in the lab - however, we do have the equivalent |
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Thu Mar 4 23:16:08 2021, Koji, Update, LSC, REFL55 demod board rework
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A new hybrid splitter (DQS-10-100) was installed. As the amplification of the final stage is sufficient for the input level of 3dBm, I have bypassed
the input amplification (Attachment 1). One of the mixer was desoldered to check the power level. With a 1dB ATTN, the output of the last
ERA-5 was +17.8dBm (Attachment 2). (The mixer was resoldered.) |
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Fri Mar 5 13:53:57 2021, gautam, Update, LSC, REFL55 demod board rework
|
0 dBm ~ 0.63 Vpp. I guess there is ~4dB total loss (3dB from splitter and 1dB from total
excess loss above theoretical from various components) between the SMA input and each RF input of the JMS-1-H
mixer, which has an advertised conversion loss of ~6dB. So the RF input to each mixer, for 0dBm to the front panel SMA is ~-4dBm (=0.4 Vpp), and the |
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Fri Mar 5 15:31:23 2021, Koji, Update, LSC, REFL55 demod board rework
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Missed to note: The IF test was done at TP7 and TP6 using pomona clips i.e. brefore the preamp.
|
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Fri Mar 5 16:24:24 2021, gautam, Update, LSC, REFL55 demod board re-installed in 1Y2
|
I don't have a good explanation why, but I too measured similar numbers to what Koji measured. The overall conversion gain for this board (including
the +20dB gain from the daughter board) was measured to be ~5.3 V/V on the bench, and ~16000 cts/V in the CDS system (100Hz offset from the LO frequency).
It would appear that the effective JMS-1-H conversion loss is <2dB. Seems fishy, but I can't find anything else obviously wrong with the circuit |
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Fri Mar 5 22:25:13 2021, gautam, Update, LSC, PRMI 1f SB locking recovered
|
Now that the REFL55 signal chain is capable of providing balanced, orthogonal readout of the two quadratures, I was able to recover the 1f SB resonant
lock pretty easily. Ran sensing lines for ~5mins, still looks weird. But I didn't try to optimize anything / do other checks (e.g. actuate MICH using
ITMs instead of BS) tonight, and I'm craving the Blueberry pie Rana left me. Will continue to do more systematic tests in the next days. |
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Thu Mar 4 23:57:35 2021, Koji, Summary, Electronics, Inspection of the new custom dsub cables 6x
|
I made the inspection of the new custom DSub cables (came from Texas).
The shelled version gives us some chance to inspect/modify the internal connections. (good)
The wires are well insulated. The conductors are wrapped with the foils and then everything is in the braid tube shield. The braid is soldered on |
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Thu Mar 4 10:54:12 2021, Paco, Anchal, Summary, LSC, POY11 measurement, tried to lock Green Yend laser
|
[Paco, Anchal]
- First ran burtgooey as last time.
- Installed pyepics on base environment of donatella |
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Thu Mar 4 11:59:25 2021, Paco, Anchal, Summary, LSC, Watchdog tripped, Optics damped back
|
Gautam came in and noted that the optics damping watchdogs had been tripped by a >5 magnitude earthquake somewhere off the coast of Australia. So,
under guided assistance, we manually damped the optics using following:
Using the scripts/SUS/reEnableWatchdogs.py script we re-enabled all the watchdogs.
Everything except SRM was restored to stable |
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Thu Mar 4 15:48:26 2021, Koji, Summary, PEM, Watchdog tripped, Optics damped back
|
EQs seen on Summary pages
https://nodus.ligo.caltech.edu:30889/detcharsummary/day/20210304/pem/seismic_blrms/ |
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Wed Mar 3 23:23:58 2021, gautam, Update, ALS, Arm cavity scan
|
I see no evidence of anything radically different from my PSL table optical characterization
in the IMC transmitted beam, see Attachment #1.
The lines are just a quick indicator of what's what and no sophisticated peak fitting has been done yet (so the apparent offset between the transmission |
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Wed Mar 3 12:00:58 2021, Paco, Anchal, HowTo, IMC, MC_F ASD
|
[Paco, Anchal]
- Saved BURT backup in /users/anchal/BURTsnaps/
- Copied existing code for mode cleaner noise budget from /users/rana/mat/mc. Will work on this from home to convert it inot new pynb way. |
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Thu Nov 14 23:56:18 2019, rana, Update, LSC, off the bad Violin filters
|
We turned off many excessive violin mode bandstop filters in the LSC.
Due to some feedforward work by Jenne or EQ some years ago, we have had ~10 violin notches on in the LSC between the output matrix and the outputs
to the SUS. |
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Fri Nov 15 11:58:12 2019, gautam, Update, LSC, off the bad Violin filters
|
The clue was that the loop X arm POX loop looked to have low (<3dB)) gain margin around 600 Hz (and again at 700 Hz). Attachment #1 shows a comparison of the OLTF for this loop (measured using
the IN1/IN2 method) before and after our change. We hypothesize that one |
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Mon Mar 1 16:27:17 2021, gautam, Update, LSC, PRM violin filter excessive?
|
The PRM violin filter seems very suboptimal - the gain peaking shows up in the MICH OLTF, presumably due to the MICH-->PRM LSC output matrix. I plot
the one used for the BS in comparison in Attachment #1,
seems much more reasonable. Why does the PRM need so many notches? Is this meant to cover some violin modes of PR2/PR3 as well? Do we really need that? |
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Tue Mar 2 13:39:31 2021, rana, Update, LSC, PRM violin filter excessive?
|
agreed, seems excessive. I always prefer bandstop over notch in case the eigenfrequency wanders, but the bandstop could be made to be just a few Hz wide.
|
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Mon Mar 1 11:40:15 2021, Anchal, Paco, Summary, IMC, getting familiar with IMC controls
|
[Paco, Anchal]
tl;dr: Done no harm, no lasting change.
Learn burtgooey
- Use /cvs/cds/caltech/target/c1psl/autoBurt.req as input to test snapshot "/users/anchal/BURTsnaps/controls_1210301_101310_0.snap" |
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Mon Mar 1 12:36:38 2021, gautam, Summary, IMC, getting familiar with IMC controls
|
Pretty minor thing - but PMCT and PMCR were switched on Quad 2 for whatever reason. I switched them back because I prefer the way it was. I have saved
snapshots of the preferred monitor config for locking but I guess I didn't freeze the arrangement of the individual quadrants within a quad. This would
be more of a problem if the ITMs and ETMs are shuffled around or something like that. |
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Sun Feb 28 16:59:39 2021, rana, gautam, Update, LSC, more PRMI checks here: what it is ain't exactly clear
|
On Friday evening we checked out a few more things, somewhat overlapping with previous tests. All tests done with PRMI on carrier lock (REFL11_I
-> PRC, AS55_Q-> MICH):
check that PRC drive appropriately minimizes in REFL55_Q. I:Q ratio is ~100:1; good enough.
put sine waves around 311 and |
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Sun Feb 28 22:53:22 2021, gautam, Update, LSC, more PRMI checks here: what it is ain't exactly clear
|
I looked into this a bit more and crossed off some of the points Rana listed. In order to use REFL 55 as a sensor, I had to fix the frequent saturations
seen in the MICH signals, at the nominal (flat) whitening gain of +18 dB. The light level on the REFL55 photodiode (13 mW), its transimpedance (400 ohm),
and this +18dB (~ x8) gain, cannot explain signal saturation (0.7A/W * 400 V/A * 8 ~ 2.2kV/W, and the PRCL PDH fringe should be ~1 MW/m, so the PDH fringe |
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Sat Feb 20 16:20:33 2021, gautam, Update, General, Housekeeping + PRMI char
|
In prep to try some of these debugging steps, I did the following.
ndscope updated from 0.7.9 to 0.11.3 on rossa. I've been testing/assisting the development for a few months now and am
happy with it, and like the new features (e.g. PDF export). v0.7.9 is still available on the system so we can revert whenever we want.
Arms |
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Sun Feb 21 20:51:21 2021, rana, Update, General, Housekeeping + PRMI char
|
I'm curious to see if the demod phase for MICH in REFL & AS chamges between thi simple Mcihelson and PRMI. IF there's a change, it could
point to a PRCL/f2 mismatch.
But I would still bet on demod chain funniness. |
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Tue Feb 23 00:10:05 2021, gautam, Update, General, Demod char part 1
|
I measured the conversion efficiencies for all the RFPD demod boards except the POP port ones. An RF source was used to drive the PD input on the demod
board, one at a time, and the I/F outputs were monitored on a 300 MHz oscilloscope. The efficiency is measured as the percentage ratio V_IF / V_RF.
I will upload the full report later, but basically, the numbers I measured today are within 10% of what I measured |
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Wed Feb 24 11:53:24 2021, gautam, Update, General, Demod char part 2
|
I measured the noise of the I/F outputs of all the LSC demodulators. I made the measurement in two conditions, one with the RF input to the demodulators
terminated with 50 ohms to ground, and the other with the RFPD plugged in, but the PSL shutter closed (so the PD dark noise was the input to the demodulator).
The LO input was driven at the nominal level for all measurements (2-3 dBm going in to the LO input, measured with the RF power meter, but I don't |
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Wed Feb 24 12:11:08 2021, gautam, Update, General, Demod char part 3
|
I did the characterization discussed at the meeting today.
RF signal at 100 Hz offset from the LO frequency was injected into the PD input on the demod boards.
The digitized CDS channels
were monitored. I chose to look at the C1:LSC-{PD}_I_OUT |
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Thu Feb 25 16:50:53 2021, gautam, Update, General, PRMI sensing matrix
|
After all the work at the LSC rack over the last couple of days, I re-locked the PRMI (ETMs misaligned), and measured the sensing matrix once again.
The PRMI was locked using 1f error signals, with AS55_Q as the MICH sensor and REFL11_I as the PRCL sensor. As shown in Attachment #1, the situation has not changed, there is still no separation |
|
Thu Feb 25 20:37:49 2021, gautam, Update, General, Setting modulation frequency and checking IMC offset
|
The Marconi frequency was tuned by looking at
The ~3.68 MHz (= 3*f1 - fIMC) peak at the IMC servo error point, TP1A, and
The ~25.8 MHz (= 5*f1 - fIMC) peak at the MC REFL
PD monitor port. The IMC error point is not a good place to look for this signal because of the post-demodulation low pass filter (indeed, I didn't |
|
Wed Nov 4 17:14:49 2020, gautam, Update, CDS, c1bhd setup
|
I am working on the setup of a CDS FE, so please do not attempt any remote login to the IPMI interface of c1bhd until I'm
done.
|
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Fri Nov 6 14:27:16 2020, gautam, Update, CDS, c1bhd setup - diskless boot
|
I was able to boot one of the 3 new Supermicro machines, which I christened c1bhd, in a diskless way (with the boot image hosted on fb, as is the case
for all the other realtime FEs in the lab). This is just a first test, but it is reassuring that we can get this custom linux kernel to boot on the new
hardware. Some errors about dolphin drivers are thrown at startup but this is to be expected since the server isn't connected to the dolphin network |
|
Thu Feb 25 14:30:05 2021, gautam, Update, CDS, new c1bhd setup - diskless boot
|
I've set up one 2U server unit received from KT in the control room area (the fans in it are pretty loud but other than that, no major issues
with it being tested here). The IPMI interface is enabled and
the machine is also hooked up to the martian network for diskless boot (usual login creds). I also installed a Dolphin interface card and the one-stop-systems |
|
Wed Feb 24 12:29:18 2021, gautam, Update, General, Input pointing recovered
|
While working at the LSC rack, I lost the input pointing into the IFO (the TT wiring situation is apparently very fragile, and this observation supports
the hypothesis that the drifting TTs are symptomatic of some electronics issue). After careful beam walking, it was recovered and the dither alignment
system was used to maximize TRX/TRY once again. No lasting damage done. If I can figure out what the pin-mapping is for the TT coils in vacuum, I'm |
|
Tue Feb 23 23:12:37 2021, Koji, Summary, SUS, SUS invacuum wiring
|
This is my current understanding of the in-vacuum wiring:
1. Facts
We have the in-air cable pinout. And Gautam recently made a prototype of D2100014 custom cable, and it worked as expected.
The |
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Mon Feb 22 14:53:47 2021, gautam, Update, CDS, dtt-ezca-tools installed on rossa
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The defaults cds-crtools didn't come with some of the older ezcautils (like ezcaread, ezcawrite etc). This is now packaged for debian, so I installled
them with sudo apt update && sudo apt install dtt-ezca-tools
on rossa. Now, we don't have to needlessly substitute the commands in our old shell scripts with the more modern |
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Fri Feb 19 13:38:26 2021, gautam, Update, LSC, PRFPMI
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I forgot that I had already done some investigation into recovering the PRFPMI lock after my work on the RF source. I don't really have any ideas
on how to explain (or more importantly, resolve) the poor seperation of MICH and PRCL sensed in our 3f (but also 1f) photodiodes, see full thread here.
Anyone have any ideas? I don't think my analysis (=code) of the sensing matrix can be blamed - in DTT, just looking the spectra of the _ERR_DQ |
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Fri Feb 19 18:22:42 2021, rana, Update, LSC, PRFPMI sensiing matrix woes
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I would:
look at the free swingin michelson. Should be able tu null that siggnal in all ports to define the Q phase.
If things are
weird, put an RF signal nto the demod board mhich is offset from the LO by ~100 Hz and verify the demod/whitening chain is kosher.
Lock PRMI |
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Fri Feb 19 15:17:51 2021, Jordan, Update, SUS, CoM Range on 3"->2" Adapter Ring for SOS
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Adjusting the thickness of the cylindrical hole for the mirror on the 2" optic sleeve, from .6875" to .61" thick, moves the CoM to 0.0003"
out of plane from the suspension wire. This is with the dumbell at its neutral point.
How close to zero do we need this to be? More fine tuning of that thickness can get it to zero, but this would require much tighter machining |
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Fri Feb 19 16:06:01 2021, Koji, Update, SUS, CoM Range on 3"->2" Adapter Ring for SOS
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We want to move the CoM with the adjustment range so that the residual deviation is adjusted by the bottom dumbbell. 0.0003" is well within the
range and good enough.
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Fri Feb 19 16:14:16 2021, gautam, Update, SUS, CoM Range on 3"->2" Adapter Ring for SOS
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I briefly talked with Jordan about this. This suspension will have OSEMs right? With 400ohm series resistance for the coil drivers, we will have ~+/-20mrad
actuation range. Of course we'd like to use as much of this for interferometry and not
static pitch alignment correction (possibly even increase the series resistance to relax the dewhitening requirements). But what is the target |
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Fri Feb 19 16:55:26 2021, Koji, Update, SUS, CoM Range on 3"->2" Adapter Ring for SOS
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Jordan's screenshot actually shows that the vertical distance (Y) is 0.0000". We want to have the vertical distance of CoM from the wire clamping
point to be 0.9mm in the nominal SOS design (this might need to be adjusted to have a similar pitch resonant freq for the different inertia of moment).
Let's say it is ~mm ish. |
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Tue Feb 16 14:56:44 2021, gautam, Update, SUS, aLIGO Sat Amp installed, powered
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[jordan, gautam]
Ran 60ft long cables from 1X4 to MC1/MC3 chamber flange, via overhead cable tray, and top of PSL enclosure for the last ~20ft. Note that
it may be that the overhead cable trays cannot support the weight of the cables for 15 SOSs (total 30 shielded cables with 37 wires as twisted pairs) when |
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Wed Feb 17 16:11:53 2021, gautam, Update, SUS, aLIGO Sat Amp installed, powered
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There is some non-trivial sign flipping in the sensors/coils in this new setup because it is a hybrid one with the old interfacing electronics (D000210,
D010001) and the new Satellite Amplifier (D080276). So I haven't yet gotten the damping working. I am leaving the PSL shutter closed and will keep
working on this today/tomorrow. I have made various changes to the c1mcs realtime model and the c1susaux database record where MC1 is concerned. I have |
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Thu Feb 18 15:33:21 2021, gautam, Update, SUS, aLIGO Sat Amp installed, powered and commissioned
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The WFS servo was recommissioned. The matrix can be tuned a bit more, but for now, I've recovered the old performance and the alignment doesn't
seem to be running away, so I defer further tuning for later. The old Satellite box was handed over to Yehonathan for his characterization of the "spare"
OSEMs. |
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Thu Feb 18 18:05:04 2021, gautam, Update, SUS, aLIGO Sat Amp characterization
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Before installation, I performed a bunch of tests on the aLIGO sat amp. All the measurements were made with the dummy suspension box substituting for
an actual suspension. Here are the results.
Attachment #1: Transimpedance |
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Thu Feb 18 20:20:25 2021, Koji, Update, SUS, aLIGO Sat Amp characterization
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Yeah, it's really inconsistent. You had 35mA LED drive and the current noise of the noisy channel was 5e-7 A/rtHz at 1Hz. The RIN is 1.4e-5 /rtHz.
The approx. received photocurrent is 30uA as we discussed today and this should make the noise around 4e-10 A/rtHz at 1Hz. However, the readout noise level
is better than this level. (well below 1e-10 A/rtHz) |
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Thu Feb 18 03:20:09 2021, Koji, Summary, Electronics, Current Rack Map
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| For your planning: |
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Fri Feb 12 15:03:48 2021, Jordan, Update, SUS, CoM on 3"->2" Adapter Ring for SOS
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As it currently stands the Center of Mass of the Adapter Ring/Optic assembly is 0.0175" out of the plane formed by the suspension wire. See Attachments.
The side plate, along with the EQ stops are hidden to show the CoM and the plane.
Note: The changes discussed in the meeting with Calum have not been added and are a work in progress. These changes include: |
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Wed Feb 17 13:59:43 2021, Koji, Update, SUS, CoM on 3"->2" Adapter Ring for SOS
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Note from today's meeting:
1. Can we adjust the thickness of the cylindrical hole for the mirror to move the COM in the plane of the wires. (We should be able to do that) |
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Wed Feb 17 13:59:35 2021, gautam, Update, DetChar, Summary pages
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The summary pages had failed because of a conda env change. We are dependent on detchar's
conda environment setup to run the scripts on the cluster. However, for some reason, when they upgraded to python3.9, they removed the python3.7 env,
which was the cause of the original failure of the summary pages a couple of weeks ago. Here is a list of thoughts on how the pipeline can be made better. |
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Thu Feb 11 18:21:39 2021, gautam, Update, SUS, MC suspension glitches
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MC1 suspension is glitching again, so this is
a good chance to install the new sat box and test it in the field. |
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Wed Jan 20 18:07:09 2021, Anchal, Summary, BHD, HAM-A Coil Driver measurements before modifications 7x
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I have taken transfer functions and noise measurements of the two HAM-A coil driver boxes D1100687 #S2100027 and #S2100028. All transfer functions look
as expected. I'm not sure about the noise measurements. If anyone sees flaw in my measurement method, please let me know. I'm not sure why in some
channels I got 10Hz harmoni peaks in the noise. That was very strange. Also let me know if my current noise estimate is wrong. |
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Mon Jan 25 18:18:04 2021, Anchal, Summary, BHD, Satellite Amplifier Transfer Functions and noise
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I took transfer function and noise measurement of satellite amplifier box's photodiode transimpedance circuit. For the measurement, I created
a makeshift connector to convert backside DB25 into DB9 with the 4 channels for PDA input. The output was taken in differential form at the front PD Output |
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Wed Feb 3 16:27:19 2021, Anchal, Summary, BHD, Satellite Amplifier Transfer Functions and noise After modifications
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I have made modifications recommended in this doc. The changes made are:
R24: 19.6k to 4.99k Ohms
R20: 19.6k to 4.99k Ohms
R23: 787 to 499 Ohms
Removed C16.
I
took transfer function measurements, fitted them with zeros and poles and plotted it against the zero |
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Wed Feb 10 11:45:59 2021, Anchal, Summary, BHD, Satellite Amplifier Very Low frequency noise After modifications 6x
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As suggested, I wrapped the satellite amplifier box D10028128 S2100029 in blanket and foam and took very low frequency spectrum starting from 32 mHz
to 3 Hz. The results are attached along with stiched high frequency measurements from 40m/15793.
Very Low Frequency Spectrum Measurement
D1002818 S2100029 box was powered and covered in a foam blanket.
Additionally, |
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Wed Feb 10 15:07:50 2021, Anchal, Summary, BHD, Satellite Amplifier Output Offset measurements
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I measured the output DC voltage of the satellite amplifier box at PDMon port when the PDA input was shorted and got following offsets:
CH
Output |
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Wed Feb 10 15:25:45 2021, gautam, Summary, BHD, Satellite Amplifier Output Offset measurements
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Why not just do this test with the dummy suspension box and CDS system? I think Rich's claim was that the intrinsic LED RIN was dominant over any
drive current noise but we can at least measure the quadrature sum of the two (which is after all the relevant quantity in terms of what performance
we can realize) and compare to a model. |
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Wed Feb 10 17:18:03 2021, Koji, Summary, BHD, Satellite Amplifier Output Offset measurements
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Testing the satellite amp i.e. PD driver
- To test the noise of the PD transimpedance amps: Leave the PD input open (do not short the terminal goes to the PD)
- To test the current noise of the LED drivers: Short the output with an appropriate Rs to have the nominal current. |
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Thu Feb 11 11:10:05 2021, Anchal, Summary, BHD, Satellite Amplifier Very Low frequency noise After modifications
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Here is a proper measurement for PD transimpedance amplifier circuit in the Satellite amplifier box D1002818 S2100029. The input from rear DB25 connector
was left open and measurement was taken with AC coupling with correction by the AC coupling transfer function (Zero at 0, pole at 160 mHz). I have calculated
the input referred displacement noise by calculating the conversion factor of OSEM in A/m. From 40m/12470, |
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Thu Feb 11 16:58:52 2021, rana, Summary, BHD, Satellite Amplifier Very Low frequency noise After modifications
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I expect that a single OSEM channel can't be better than 1e-10 m/rHz above 5 Hz, so probably something wrong in the calibration. 1.6 V/mm seems right
to me, so could be some place else. |
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Thu Jan 28 12:53:14 2021, Anchal, Summary, BHD, HAM-A Coil Driver measurements before modifications
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I took some steps to reduce the coupling of 60 Hz harmonics in noise measurement. The box was transferred to the floor instead of on top of another instrument.
Measurement was immediately converted into single-ended using SR560 in battery mode with a gain of 10. All of the setups was covered in aluminum foil to
increase isolation. |
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Thu Jan 28 18:04:55 2021, Anchal, Summary, BHD, HAM-A Coil Driver measurements After modifications
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I did the recommended modifications on of the boards with serial number
S2100028. These included:
R13, R27: 160 -> 75
C11, C21: 470 nF -> 68nF
C19: 4.7 uF -> 470 nF
R15: 3.23 kOhm -> 1.82 |
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Thu Jan 28 21:44:45 2021, gautam, Summary, BHD, HAM-A Coil Driver measurements After modifications
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Looks fine to me visually but the verdict can only be made once the z:p locations are quantitatively confirmed, and the noise tests
pass. It would be interesting to see what kind of time-domain transient (in N of force) switching on the de-whitening introduces, i guess best done interferometrically.
Quote:
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Fri Jan 29 15:39:30 2021, Anchal, Summary, BHD, HAM-A Coil Driver measurements After modifications TF and Noise S2100027
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I fitted zeros and poles in the measured transfer function of D1100687 S2100027 and got zeros at 130 Hz and 234 Hz and poles at 10Hz and 2845 Hz. These
values are different from the aimed values in this doc, particularly the 234Hz zero which was aimed at 530 Hz in the doc.
I also took the noise measurement using the same method as described in 40m/15780. |
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Tue Feb 2 11:57:46 2021, Anchal, Summary, BHD, HAM-A Coil Driver measurements After modifications TF and Noise S2100028
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I have made the modifications on the other board D1100687 S2100028 as well. The measurements were taken as mentioned in 40m/15784.
All conclusions remain the same as 40m/15784. The attached zip file contains all measurement
data, before and after the modifications. |
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Wed Feb 10 14:14:58 2021, gautam, Update, Electronics, Custom cables received
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We received the custom cables to test the new suspension electronics. They are under my desk. So we are ready.
This batch was a small one - the company says that they can make molded cables if we have a minimum order, something to consider I gues.s.
Update 1900 11 Feb: I verified that the pin outs of the cables are as we intended (for one set of each type of cable). |
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Tue Feb 2 23:29:35 2021, Koji, Update, CDS, CDS crash and CDS/IFO recovery
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I worked around the racks and the feedthru flanges this afternoon and evening. This inevitably crashed c1lsc real-time process.
Rebooting c1lsc caused multiple crashes (as usual) and I had to hard reboot c1lsc/c1sus/c1ioo
This made the "DC" indicator of the IOPs for these hosts **RED**. |
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Wed Feb 3 15:24:52 2021, gautam, Update, CDS, CDS crash and CDS/IFO recovery
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Didn't get a chance to comment during the meeting - This was almost certainly a coincidence. I have never had to do this - I assert,
based on the ~10 labwide reboots I have had to do in the last two years, that whether the timing errors persist on reboot or not is not deterministic.
But this is beyond my level of CDS knowledge and so I'm happy for Rolf / Jamie to comment. I use the reboot script - if that doesn't work, I use |
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Wed Feb 3 18:53:31 2021, Koji, Update, CDS, CDS crash and CDS/IFO recovery
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Really!? I didn't reboot the machines between "sudo date" and "rtcds start c1x0*". I tried rtcds. If it didn't work, it used
date. Then tried rtcds. (repeat) The time was not synched at all wrt the time zones and also the time. There were 1~3 sec offset besides the TZ problem.
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Wed Feb 3 21:28:02 2021, gautam, Update, CDS, CDS crash and CDS/IFO recovery
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I am just reporting my experience - this may be a new failure mode but I don't think so. In the new RTCDS, the ntp server for the FEs are the FB,
to which they are synced by timesyncd. The FB machine itself has the ntpd service installed, and so is capable of synching to an NTP server over the internet,
but also serving as an NTP server for the FEs. The timesyncd daemon may not have started correctly, or the NTP serving from FB got interrupted (for example), |
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Tue Jan 12 08:21:47 2021, anchal, HowTo, CDS, Acromag wiring investigation
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I used an Acromag XT1221 in CTN to play around with different wiring and see what works. Following are my findings:
Referenced Single Ended Source (Attachment 1):
If the source signal is referenced single ended,
i.e. the signal is only on the positive output and the negative side is tied to GND |
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Tue Jan 12 11:42:38 2021, gautam, HowTo, CDS, Acromag wiring investigation
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Thanks for the systematic effort.
Can you please post some time domain plots (ndscope perferably or StripTool) to clearly show the different failure modes?
The
majority of our AI channels are "Referenced Single Ended Source" in your terminology. At least on the c1psl Acromag crate, there are no channels |
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Wed Jan 13 16:09:29 2021, Anchal, HowTo, CDS, Acromag wiring investigation
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I'm working on a better wiring diagram that takes into account multiple power supplies, how their GND is passed forward to the circuits or sensors
using those power supplies and what possible wiring configurations on Acromag would give low noise. I think I have two configurations in mind which I will
test and update here with data and better diagrams. |
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Tue Jan 26 12:59:51 2021, Anchal, HowTo, CDS, Acromag wiring investigation
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Taking inspiration from SR785 on how it reads differential signal, I figured that acromag too always need a way to return current through RTN ports always.
That must be the reason why everything goes haywire when RTN is not connected to IN-. Now for single ended signals, we can always short RTN to IN- and
keep same GND but then we need to be careful in avoiding ground loops. I'm gonna post a wiring diagram in next post to show how if two signal sources |
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Tue Jan 26 15:37:25 2021, Anchal, HowTo, CDS, Acromag wiring investigation
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Here I present few wiring diagrams when using Acromag to avoid noisy behavior and ground loops.
Case 1: Only single-ended sources
Attachment 1 gives a functioning wiring diagram
when all sources are single ended.
One should always short the RTN to IN- pin if the particular GND carried by that signal has not been shorted |
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Fri Jan 29 17:57:17 2021, Anchal, HowTo, CDS, Acromag wiring investigation
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I found a
white paper from Acromag which discusses how to read differential signal using Acromag units. The document categorically says that differential
signals are always supposed to be transmitted in three wires. I provides the two options of either using the RTN to connect to the signal ground (as done |
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Thu Jan 28 22:34:21 2021, gautam, Update, SUS, De-whitening
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Summary:
We will need de-whitening filters for the BHD relay optics in order to meet the displacement noise requirements set out in the DRD.
I think these need not be remotely switchable (depends on specifics of LO phase control scheme). SR2, PR2 and PR3 can also have the |
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Tue Jan 26 10:58:30 2021, gautam, Update, SUS, MC2 tickler stuck on
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For whatever reason, the autolocker didn't turn the tickle off for several
hours. Seems to work okay now. The linked plot suggests that the coil balancing on MC2 is pretty lousy. |
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Wed Jan 20 19:12:16 2021, gautam, Update, CDS, SLwebview fixed
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After fixing multiple issues, the model webviews are updating, should be done by tomorrow. It should be obvious from the timestamps on the index
page which are the new ones. These new screens are better than the old ones and offer more info/details. Please look at them, and let me know if
there are broken links etc. Once we are happy with this new webview, we can archive the old files and clean up the top directory a bit. I don't |
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Fri Dec 18 22:59:12 2020, Jon, Configuration, CDS, Updated CDS upgrade plan
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Attached is the layout for the "intermediate" CDS upgrade option, as was discussed on Wednesday. Under this plan:
Existing FEs stay where they are (they are not moved to a single rack)
Dolphin IPC remains PCIe Gen 1 |
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Mon Dec 21 09:28:50 2020, Jamie, Configuration, CDS, Updated CDS upgrade plan
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Quote:
Attached is the layout for the "intermediate" CDS upgrade option, as was discussed on Wednesday.
Under this plan: |
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Wed Dec 23 23:06:45 2020, gautam, Configuration, CDS, Updated CDS upgrade plan
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The diagram should clearly show the host machines and the expansion chassis and the interconnects between them.
We no longer have
any Gentoo bootserver or diskless FEs.
The "c1lsc" host is in 1X4 not 1Y3.
The connection between c1lsc and Dolphin switch
is copper not fiber. I don't know how many Gbps it is. But if the switch is 10 Gbps, are they really selling interface cables that have lower speed? |
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Tue Jan 19 14:05:25 2021, Jon, Configuration, CDS, Updated CDS upgrade plan
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I've produced updated diagrams of the CDS layout, taking the comments in 15476 into
account. I've also converted the 40m's diagrams from Omnigraffle ($150/license) to the free, cloud-based platform draw.io.
I had never heard of draw.io, but I found that it has most all the same functionality. It also integrates nicely with Google Drive. |
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Tue Jan 19 15:43:24 2021, gautam, Configuration, CDS, Updated CDS upgrade plan
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Not sure if 1Y1 can accommodate both c1sus2 and c1bhd as well as the various electronics chassis that will have to be installed. There may need to be
some distribution between 1Y1 and 1Y3. Does Koji's new wiring also specify which racks hold which chassis?
Some minor improvements to the diagram: |