ID |
Date |
Author |
Type |
Category |
Subject |
16121
|
Wed May 5 13:05:07 2021 |
Chub | Update | General | chassis delivery from De Leone |
Assembled chassis from De Leone placed in the 40 Meter Lab, along the west wall and under the display pedestal table. The leftover parts are in smaller Really Useful boxes, also on the parts pile along the west wall. |
Attachment 1: de_leone_del_5-5-21.jpg
|
|
16160
|
Tue May 25 17:08:17 2021 |
Chub | Update | Electronics | chassis rework complete! |
All remaining chasses have been reworked and placed on the floor along the west wall in Room 104. |
Attachment 1: 40M_chassis_reworked_5-25-21.jpg
|
|
428
|
Fri Apr 18 19:46:08 2008 |
rana | Update | ASS | check adaptive |
I restarted the adaptive code today using 'startass' and 'upass'.
I moved them into the scripts/ASS/ subdirectory.
Things seem OK. With a MU=0.03 and a TAU=0.00001, there is a still
a good factor of 10 reduction of the 3 Hz stack peak from the MC2
drive by doing FF into MC1.
I edited the ASS-TOP screen so that we could see such small numbers. I
also re-aligned the MC SUS to match the input beam (mainly MC3). The
cavity was locking on a TEM10 mode mostly -- we should look in the SUS
OSEM trends to see if MC3 has moved a lot in the last month or so.
Caryn Palatchi (a Caltech undergrad who just started working with us)
illustrated to me today that using even 1000 FIR taps is not very effective
for low frequency noise cancellation if you have a 2048 Hz sample rate. More
precisely, the asymptotic Wiener filter which our 'LMS' algorithm converges
to, can often amplify the noise at frequencies below f_sample/N_taps.
A less obvious thing that she also noticed is that there is almost no cancellation
of the 16.25 Hz bounce mode when using such a short filter. That's because that
mode is fairly high Q: the transfer function from the Z-ACC to the cavity signal
goes through the high-Q vertical suspension resonance; the FF signal we send back
goes through the low-Q horizontal pendulum response only. Therefore the filter
needs to be able to simulate ~100 cycles at 16.25 Hz in order to cancel that peak.
Duh.
The message here is: we need to find a computationally efficient way to do FIR filtering
or its not going to ever be cool enough to help us find the Crab. |
Attachment 1: 0052_xray_thm45.jpg
|
|
432
|
Mon Apr 21 12:58:42 2008 |
rob | Update | ASS | check adaptive |
Quote: |
Caryn Palatchi (a Caltech undergrad who just started working with us)
illustrated to me today that using even 1000 FIR taps is not very effective
for low frequency noise cancellation if you have a 2048 Hz sample rate. More
precisely, the asymptotic Wiener filter which our 'LMS' algorithm converges
to, can often amplify the noise at frequencies below f_sample/N_taps.
A less obvious thing that she also noticed is that there is almost no cancellation
of the 16.25 Hz bounce mode when using such a short filter. That's because that
mode is fairly high Q: the transfer function from the Z-ACC to the cavity signal
goes through the high-Q vertical suspension resonance; the FF signal we send back
goes through the low-Q horizontal pendulum response only. Therefore the filter
needs to be able to simulate ~100 cycles at 16.25 Hz in order to cancel that peak.
Duh.
The message here is: we need to find a computationally efficient way to do FIR filtering
or its not going to ever be cool enough to help us find the Crab. |
This is the reason for "RDNSAMP" parameter in the ASS code. The FIR filtration is applied at the downsampled rate, not the machine rate. So, if RDNSAMP=32, the effective sampling rate of the FIR filter is 64Hz, and thus noise cancellation should be good down to 64Hz/1000, or 64mHz, and the filter has an impulse response time that extends to 15 secs. I'm not convinced the filter length is what's limiting the performance at the bounce mode, but I agree that a faster FIR implementation would be good. |
4327
|
Fri Feb 18 20:06:59 2011 |
kiwamu | Summary | SUS | check f2p function on ETMX |
The plot below shows how the f2p filters work.
At -2 min I turned on the f2p filters.
 |
5161
|
Wed Aug 10 00:11:39 2011 |
jamie | Update | SUS | check of input diagnolization of ETMX after OSEM tweaking |
Suresh and I tweaked the OSEM angles in ETMX yesterday. Last night the ETMs were left free swinging, and today I ran Rana's peakFit scripts on ETMX to check the input diagnolization:

It's well inverted, but the matrix elements are not great:
pit yaw pos side butt
UL 0.3466 0.4685 1.6092 0.3107 1.0428
UR 0.2630 -1.5315 1.7894 -0.0706 -1.1859
LR -1.7370 -1.5681 0.3908 -0.0964 0.9392
LL -1.6534 0.4319 0.2106 0.2849 -0.8320
SD 1.0834 -2.6676 -0.9920 1.0000 -0.1101
The magnets are all pretty well centered in the OSEMS, and we worked at rotating the OSEMS such that the bounce mode was minimized.
Rana and Koji are working on ETMY now. Maybe they'll come up with a better procedure. |
3807
|
Thu Oct 28 04:28:50 2010 |
yuta | Update | Green Locking | checked frequency counter SR620 |
(Kiwamu, Yuta)
Background:
For green locking, we are planning to feedback frequency differential signal to ETM suspension for the final configuration.
We don't have ETM suspension control system right now, so we are going to feedback the signal to X-end laser frequency for a test.
We have two loops for the servo;
1. coarse locking using frequency counter, feeding back to the laser temperature
2. using VCO, feeding back to the laser PZT
Today, we checked frequency counter SR620 and see how to get the small beat note signal(-48dBm; see elog #3771).
What we did:
1. Using Marconi(RF signal generator), put RF signals to SR620 and see how small signal SR620 can see.
It depends on the frequency. For 80MHz signal, you need more than about -9dBm.
60MHz >-12dBm
70MHz >-10dBm
80MHz >-9dBm
90MHz >-8dBm
100MHz >-7dBm
Since we are going to lock the frequency difference between X-end and PSL to 80MHz, we need at least +40dBm amp before putting the signal into SR620.
RF amplifier ZHL-32A has around +28dBm +28dB gain at 80MHz, so we need 2 of them.
2. Marconi -> ZHL-32A -> ZHL-32A -> SR620 and see how small 80MHz signal SR620 can see.
Around -68dBm. This should be enough.
3. SR620 has "STRIP CHART" output on the rear panel. The output voltage is proportional to the mean frequency of the input.
The output range is 0-8V. So in order to get 4V for 80MHz, set SCALE to 20MHz.
Plan:
- find green beat again and see if SR620 can see it with double ZHL-32A configuration |
3809
|
Thu Oct 28 11:54:31 2010 |
Koji | Update | Green Locking | checked frequency counter SR620 |
ZHL-32A is a high power (well..., actually middle power) amplifier with the max output power of +29dBm (~1W!).
It seems to be overkill.
Your signal is so small so you don't need ZHL-32A, but can use small amp which we may have somewhere in the lab.
And the description:
"RF amplifier ZHL-32A has around +28dBm gain at 80MHz"
The unit is wrong.
Quote: |
(Kiwamu, Yuta)
Background:
For green locking, we are planning to feedback frequency differential signal to ETM suspension for the final configuration.
We don't have ETM suspension control system right now, so we are going to feedback the signal to X-end laser frequency for a test.
We have two loops for the servo;
1. coarse locking using frequency counter, feeding back to the laser temperature
2. using VCO, feeding back to the laser PZT
Today, we checked frequency counter SR620 and see how to get the small beat note signal(-48dBm; see elog #3771).
What we did:
1. Using Marconi(RF signal generator), put RF signals to SR620 and see how small signal SR620 can see.
It depends on the frequency. For 80MHz signal, you need more than about -9dBm.
60MHz >-12dBm
70MHz >-10dBm
80MHz >-9dBm
90MHz >-8dBm
100MHz >-7dBm
Since we are going to lock the frequency difference between X-end and PSL to 80MHz, we need at least +40dBm amp before putting the signal into SR620.
RF amplifier ZHL-32A has around +28dBm gain at 80MHz, so we need 2 of them.
2. Marconi -> ZHL-32A -> ZHL-32A -> SR620 and see how small 80MHz signal SR620 can see.
Around -68dBm. This should be enough.
3. SR620 has "STRIP CHART" output on the rear panel. The output voltage is proportional to the mean frequency of the input.
The output range is 0-8V. So in order to get 4V for 80MHz, set SCALE to 20MHz.
Plan:
- find green beat again and see if SR620 can see it with double ZHL-32A configuration
|
|
3842
|
Mon Nov 1 23:31:05 2010 |
yuta | Update | CDS | checked input hardware filter in single frequency |
Background:
For input filter, we have analog whitening filter and also digital whitening filter. They have the same TF and when analog one is off, digital one should be on and vice versa.
I made a python script that checks the switching automatically.
Method:
Excite the suspension in a single frequency and see sensor inputs(XXSEN_IN1).
Calculate the magnitude in the excitation frequency and compare it when digital whitening is off and on.
When digital whitening is off, analog should be on, so sensor inputs should gone though the analog filter. That means the signal is multiplied by the TF of that filter, which makes the difference.
We currently don't have excitation and I thought I have to wait, but instead of putting some extra excitation, I found that 60Hz line noise is useful.
Script:
The script is /cvs/cds/caltech/users/yuta/scripts/WDWchecker.py
For every sensor input, it;
0. Stores current filter switching(XXSEN_SW1R)
1. turns OFF the digital filter(FM1, using ezcaswitch)
2. tdsdmd XXSEN_IN1 in 60Hz
3. turns ON the digital filter
4. tdsdmd XXSEN_IN1 in 60Hz
5. divides mag(2.) by mag(4.) and calculate the analog filter gain in 60Hz
6. Restores the filter switching in the state before the checking
Result:
The results are;
C1:SUS-BS_ULSEN_IN1: 22.2 dB
C1:SUS-BS_URSEN_IN1: 18.7 dB
C1:SUS-BS_LRSEN_IN1: 22.7 dB
C1:SUS-BS_LLSEN_IN1: 16.0 dB
C1:SUS-BS_SDSEN_IN1: 21.5 dB
C1:SUS-ITMX_ULSEN_IN1: 16.9 dB
C1:SUS-ITMX_URSEN_IN1: 16.3 dB
C1:SUS-ITMX_LRSEN_IN1: 17.5 dB
C1:SUS-ITMX_LLSEN_IN1: 17.1 dB
C1:SUS-ITMX_SDSEN_IN1: 6.2 dB
C1:SUS-ITMY_ULSEN_IN1: 15.5 dB
C1:SUS-ITMY_URSEN_IN1: 16.5 dB
C1:SUS-ITMY_LRSEN_IN1: 17.4 dB
C1:SUS-ITMY_LLSEN_IN1: 16.3 dB
C1:SUS-ITMY_SDSEN_IN1: 18.0 dB
C1:SUS-PRM_ULSEN_IN1: 0.1 dB
C1:SUS-PRM_URSEN_IN1: 10.3 dB
C1:SUS-PRM_LRSEN_IN1: 13.1 dB
C1:SUS-PRM_LLSEN_IN1: -32.3 dB
C1:SUS-PRM_SDSEN_IN1: 14.6 dB
C1:SUS-SRM_ULSEN_IN1: 17.3 dB
C1:SUS-SRM_URSEN_IN1: 13.5 dB
C1:SUS-SRM_LRSEN_IN1: 1.6 dB
C1:SUS-SRM_LLSEN_IN1: 16.7 dB
C1:SUS-SRM_SDSEN_IN1: 18.3 dB
C1:SUS-MC1_ULSEN_IN1: 17.0 dB
C1:SUS-MC1_URSEN_IN1: 18.6 dB
C1:SUS-MC1_LRSEN_IN1: 14.9 dB
C1:SUS-MC1_LLSEN_IN1: 27.0 dB
C1:SUS-MC1_SDSEN_IN1: 16.6 dB
C1:SUS-MC2_ULSEN_IN1: 19.8 dB
C1:SUS-MC2_URSEN_IN1: 14.0 dB
C1:SUS-MC2_LRSEN_IN1: 20.8 dB
C1:SUS-MC2_LLSEN_IN1: 16.1 dB
C1:SUS-MC2_SDSEN_IN1: 17.3 dB
C1:SUS-MC3_ULSEN_IN1: 15.5 dB
C1:SUS-MC3_URSEN_IN1: 17.3 dB
C1:SUS-MC3_LRSEN_IN1: 18.2 dB
C1:SUS-MC3_LLSEN_IN1: 18.7 dB
C1:SUS-MC3_SDSEN_IN1: 16.8 dB
Whitening filter has 18dB gain at 60Hz. (It's 3Hz pole, 30Hz zero, 100Hz zero and 0dB at DC)
So, from the result, at least MC suspensions look like they have correct switching.
But some channels doesn't look ok.
We have to check those.
Plan:
- check ITMX_SDSEN, PRM_ULSEN, PRM_LLSEN, SRM_LRSEN input filters
- check the script and see if the script can really check. maybe the script needs some adjustments (# of averaging, multiple frequency, ......)
- make AWG(, tdssine) work
- check output hardware filter
By the way:
fb is back. I don't know why. With help from Joe, I just compiled c1mcs again and again changing number of RFM channels. |
3675
|
Thu Oct 7 23:24:44 2010 |
yuta | Update | CDS | checking MC1 suspension damping |
Background:
The new CDS is currently being set up.
We want to see if the damping servo of the suspensions are working correctly.
But before that, we have to see if the sensors and the coils are working correctly.
Among the 8 optics, MCs take top priority because of the green beam. for the alignment of the in-vac optics.
What I did:
By seeing the 5 sensor outputs (C1:SUS-MC1_XXSEN_IN1, XX=UL,UR,LR,LL,SD) with the Data Viewer, I checked if all the coils are kicking in the supposed direction and all the sensors are sensing that kick correctly.
All the matrices elements were set to the ideal values(-1 or 0 or 1) this time.
Result:
They were perfect.
1. POSITION seemed to be POSITION
When the offset(C1:SUS-MC1_SUSPOS_OFFSET) was added, all the sensor output moved to the same direction.
2. PITCH seemed to be PITCH
When the offset(C1:SUS-MC1_PIT_COMM) was changed, UL&UR and LL&LR went to the different direction.
3. YAW seemed to be YAW
When the offset(C1:SUS-MC1_YAW_COMM) was changed, UL&LL and UR&LR went to the different direction.
4. SIDE seemed to be SIDE
When the offset(C1:SUS-MC1_SDSEN_OFFSET) was added, DC level of the SD sensor output changed.
Notes:
c1mcs crashed many times during the investigation, and I had to kill and restart it again and again.
It seemed to be easily crashed when filters are on, and so I couldn't check whether the damping servo is working correctly or not today.
Next work:
- fix c1mcs (and maybe others)
- check the damping servo by comparing the displacements of each 4 degrees of freedom when servo in off and on. |
3678
|
Fri Oct 8 12:21:11 2010 |
josephb | Update | CDS | checking MC1 suspension damping |
Upon investigation, it appears that the c1mcs model was (and still is) timing out after a random amount of time. Or in other words, it at some point it was taking too long to do all the calculations for a single cycle and falling behind. The evidence for this is from the dmesg command when run on c1sus.
There's a bunch of lines like:
[ 8877.438002] c1mcs: cycle 568 time 62; adcWait 0; write1 0; write2 0; longest write2 0
[ 8877.438002] c1mcs: cycle 569 time 62; adcWait 0; write1 0; write2 0; longest write2 0
With a final line like: [ 8877.439003] c1mcs: ADC TIMEOUT 1 2405 37 2277
This last line indicates in fell so far behind it gave up.
However, this doesn't actually seem to be related to the amount of computation going on with the front end. I restarted the c1mcs model this morning by logging into the c1sus machine, and changing to the /opt/rtcds/caltech/c1/target/c1mcs/bin directory and running:
lsmod
sudo rmmod c1mcsfe
sudo insmod c1mcsfe.ko
The first line just lists the running modules. The second removes the c1mcs module, and the third starts it up again.
I proceeded to turn all the filters and and set all the matrix values while keeping an eye on the C1MCS-GDS_TP.adl screen and its timing indicator. It was running fine with all these turned on. Then I ran a dtt session from rosalba (going to /opt/apps/, typing bash, then source gds-env.bash, and finally diaggui) as well as a dataviewer and looked at 6 test point channels. It received data fine.
However, about 2 minutes after I had stopped doing this (although the dataviewer realtime session was still going) the USR timing jumped from about 20 microseconds to 35 microseconds, and the CPU Max timing jumped to the 50-60 microsecond range. At this point dmesg started reporting things like:
[54143.465613] c1mcs: cycle 1076 time 62; adcWait 0; write1 0; write2 0; longest write2 0
[54143.526004] c1mcs: cycle 2064 time 62; adcWait 0; write1 0; write2 0; longest write2 0
About a minute later the code gave up and reported a ADC timeout via dmesg. None of the other front ends seem to be affected.
I had to clear the test points manually after stopping dataviewer and dtt by going to rosalaba,using the sourced gds-env.bash, and running diag -l. I then typed "tp clear 36 *" to clear all the test points on the model with FEC number 36 (corresponding to c1mcs).
I removed and restarted c1mcs again, trying to turn on a few things at a time and letting it run for a few minutes to see if I could narrow down if its one particular filter perhaps reaching an underflow and starting to bog down the computations. However, after about 45 minutes of this, the model is still running and I've turned all the filters on and have been running about 8 test points with no problem, so the problem is clearly intermittent.
Quote: |
Notes:
c1mcs crashed many times during the investigation, and I had to kill and restart it again and again.
It seemed to be easily crashed when filters are on, and so I couldn't check whether the damping servo is working correctly or not today.
Next work:
- fix c1mcs (and maybe others)
- check the damping servo by comparing the displacements of each 4 degrees of freedom when servo in off and on.
|
|
4077
|
Mon Dec 20 16:57:58 2010 |
steve | Update | IOO | checking out & closing the vacuum chambers |
- Check EQ-stops
- clamp down counter weights
- check other components are clamped
- remove all tools
- check cabling is not is not shorting out seismic stack or blocking beam
- confirm well centered spots on mirrors
|
3849
|
Wed Nov 3 02:23:11 2010 |
yuta | Summary | CDS | checking whitening filter board |
Summary:
Last night, I found that some of the input channels have wrong hardware filter switching(see elog #3842).
So, to check the whitening board(D000210), I swapped the one with ok switching and bad switching.
During the checking, I somehow broke the board.
I fixed it, and now the status is the same as last night (or, at least look like the same).
What I did:
1. Switching for SRM_LRSEN looked bad and every input channel for MC3 looked OK.
So, I unplugged the whitening board for SRM (1X5-1-5B) and plugged it into MC3's place(1X5-1-8B).
2. Ran WDWchecker.py for MC3. The switching seemed OK for every input channel, which means the whitening board was not the wrong one.
3. Swapped back the whitening board as it was.
4. Found MC3_ULSEN_OUT and MC3_LLSEN_OUT was keep showing negative value(they should be positive).
5. Check the board and found that one of LT1125 for UL/LL was wrong (broken virtual ground).
6. Replaced LT1125 and put the board back to 1X5-1-8B.
7. Checked the board with WDWchecker.py and dataviewer 5-hour minute trend.
The input signal came back to normal value(Attachment #1), MC3 damping working, input filter switching seems working
before LT1125 replacement |
after LT1125 replacement |
C1:SUS-MC3_ULSEN_IN1: -2.4 dB [!]
C1:SUS-MC3_URSEN_IN1: 16.9 dB
C1:SUS-MC3_LRSEN_IN1: 15.4 dB
C1:SUS-MC3_LLSEN_IN1: -1.1 dB [!]
C1:SUS-MC3_SDSEN_IN1: 18.4 dB
|
C1:SUS-MC3_ULSEN_IN1: 18.2 dB
C1:SUS-MC3_URSEN_IN1: 17.6 dB
C1:SUS-MC3_LRSEN_IN1: 16.6 dB
C1:SUS-MC3_LLSEN_IN1: 17.1 dB
C1:SUS-MC3_SDSEN_IN1: 16.2 dB |
Result:
The whitening board seems OK.
The wrong one is either wiring or RT model. Or, the checking script.
|
Attachment 1: MC3SEN.png
|
|
3748
|
Wed Oct 20 21:43:25 2010 |
yuta | Update | CDS | checking whitening filters for MCs and messed up |
(Joe, Yuta)
Background:
We found that the damping servo for MC suspensions somehow worked when we turned off the 13Hz Chebyshev filters.
But that does not meet our satisfaction, so we started checking every components.
First of all is the whitening filters.
If we turn on a digital whitening filter(WF), corresponding analog WF should turn off, and vice versa.
Reference:
See DCC #D000210 for the analog circuit of WF. WF has 3Hz zero, 30Hz pole, 100Hz pole. MAX333A bypasses analog WF when supplied +15V(HIGH).
What we did:
1. Compared the transfer function between MC2_SUSPOS_EXC and MC2_ULSEN_IN1 when digital WF on and off. When digital is on/off, analog should be off/on, so there should be difference but couldn't see.
2. We went through the simulink model and found 2 mistakes in the logic. One is the conflict with other optics. Even if we turn on/off digital WF of MC2, it didn't switched analog WF of MC2. Two is the additional bit invert (but it turned out to be our misunderstanding).
3. We (thought we) fixed it, rebuild it, and measured the TF again.(Attachment #1)
[Attached #1]
The red/blue line is when digital WF is on/off. Blue should be bigger(+10dB @ 10Hz according to (analog) WTF) than red, but it was the opposite.
4. To confirm that they are doing the opposite, I checked MAX333A input(pin#1,10,11,20) in "SUS PD Whitening Board" at 1X5-1-8B (which is for MC3) and found that switching is opposite. When I turned off/on the digital WF, MAX333A input was +15V/0V. It should be 0V/+15V.
5. Also, I found that LLSEN digital WF switch switches LRSEN analog WF and vice versa.
[Attached #2]
Transfer functions between MC2_SUSPOS_EXC and MC2_LRSEN_IN1 with;
Red: LR digital off, LL digital on
Blue: LR digital off, LL digital off
Green: LR digital on, LL digital off
As you can see, LL switch is the one which switches LR analog WF now.
Conclusion:
Currently, digital WF on/off corresponds to analog WF on/off.
Also, LL/LR digital WF switch is LR/LL analog WF switch now.
Next work:
- fix the simulink models (or wiring)
- check dewhitening filters
Schematic:
- whitening
MC1 5 PD outputs -> SUS PD Whitening Board(D000210) -> ... (digital WF=3,100:3)
MC2 5 PD outputs -> SUS PD Whitening Board(D000210) -> ... (digital WF=3,100:3)
MC3 5 PD outputs -> SUS PD Whitening Board(D000210) -> ... (digital WF=3,100:3)
D000210 has switches for bypassing analog WT(3,100:3). HIGH to bypass.
- dewhitening
(-) ... -> SOS Dewhitening Board(D000316) -> MC1,3 UL/UR/LR/LL coils
(-) ... -> SOS Dewhitening Board(D000316) -> MC1,2,3 SIDE coils
(SimDW)(InvDW) ... -> LSC Anti-imaging Board(D000186) -> Universal Dewhitening Board(D000183) -> MC2 UL/UR/LR/LL coils
D000316 has switches for bypassing 28Hz elliptic LPF. HIGH to bypass.
D000186 is 7570Hz elliptic LPFs.
D000183 has switches for bypassing dewhitening filter. HIGH to bypass.
See this wiki page for more comprehensive setup. |
Attachment 1: MC2ULSEN.png
|
|
Attachment 2: MC2LRSEN.png
|
|
12942
|
Thu Apr 13 19:54:07 2017 |
rana | Update | DAQ | checkup on minute trends |
Our minute trends are still not available through NDS2 from the outside world due to the bad config of the DAQ, but I can confirm that we still have the minute-raw capability. This is 111 days of Seismic BLRMS.
However, it seems we're only able to get ~1 week of lookback on our second trends and that is low-down dirty shame. We used to have over a month of second trend lookback before the last decade of 'upgrades'. |
Attachment 1: BRLMS-trend.png
|
|
14359
|
Fri Dec 14 14:25:36 2018 |
Koji | Update | CDS | chiara backup |
fsck of chiara backup disk (UUID="90a5c98a-22fb-4685-9c17-77ed07a5e000") was done. But this required many files to be fixed. So the backed-up files are not reliable now.
On the top of that, the disk became not recognized from the machine.
I went to the disk and disconnected the USB and then the power supply, which was/is connected to the UPS.
Then they are reconnected again. This made the disk came back as /media/90a5c98a-22fb-4685-9c17-77ed07a5e000. (*)
After unmounting this disk, I ran "sudo mount -a" to follow the way of mounting as fstab does.
Now I am running the backup script manually so that we can pretend to maintain a snapshot of the day at least.
(*) This is the same situation we found at the recovery from the power shutdown. So my hypothesis is that on Oct 16 at 7 AM during the backup there was a USB failure or disk failure or something which unmounted the disk. This caused some files got damaged. Also this caused the disk mounted as /media/90a5c98a-22fb-4685-9c17-77ed07a5e000. So since then, we did not have the backup.
Update (20:00): The disk connection failed again. I think this disk is no longer reliable.
|
Attachment 1: fsck_log.log
|
sudo fsck -yV UUID="90a5c98a-22fb-4685-9c17-77ed07a5e000" [238/276]
[sudo] password for controls:
fsck from util-linux 2.20.1
[/sbin/fsck.ext4 (1) -- /media/40mBackup] fsck.ext4 -y /dev/sde1
e2fsck 1.42 (29-Nov-2011)
/dev/sde1 contains a file system with errors, check forced.
Pass 1: Checking inodes, blocks, and sizes
Error reading block 527433852 (Attempt to read block from filesystem resulted in
short read) while getting next inode from scan. Ignore error? yes
... 283 more lines ...
|
16307
|
Thu Sep 2 17:53:15 2021 |
Paco | Summary | Computers | chiara down, vac interlock tripped |
[paco, koji, tega, ian]
Today in the morning the name server / network file system running in chiara failed. This resulted in donatella/pianosa/rossa shell prompts to hang forever. It also made sitemap crash and even dropping into a bash shell and just listing files from some directory in the file system froze the computer. Remote ssh sessions on nodus also had the same symptoms.
A little after 1 pm, we started debugging this issue with help from Koji. He suggested we hook a monitor, keyboard, and mouse onto chiara as it should still work locally even if something with the NFS (network file system) failed. We did this and then we tried for a while to unmount the /dev/sdc1/ from /home/cds/ (main file system) and mount /dev/sdb1/ from /media/40mBackup (backup copy) such that they swap places. We had no trouble unmounting the backup drive, but only succeeded in unmounting the main drive with the "lazy" unmount, or running "umount -l". Running "df" we could see that the disk space was 100% used, with only ~ 1 GB of free space which may have been the cause for the issue. After swapping these disks by editing the /etc/fstab file to implement the aforementioned swapping, we rebooted chiara and we recovered the shell prompts in all workstations, sitemap, etc... due to the backup drive mounting. We then started investigating what caused the main drive to fill up that quickly, and noted that weirdly now the capacity was at 85% or about 500GB less than before (after reboot and remount), so some large file was probably dumped into chiara that froze the NFS causing the issue.
At this point we tried opening the PSL shutter to recover the IMC. The shutter would not open and we suspected the vacuum interlock was still tripped... and indeed there was an uncleared error in the VAC screen. So with Koji's guidance we walked to the c1vac near the HV station and did the following at ~ 5:13 PM -->
- Open V4; apart from a brief pressure spike in PTP2, everything looked ok so we proceeded to
- Open V1; P2 spiked briefly and then started to drop. Then, Koji suggested that we could
- Close V4; but we saw P2 increasing by a factor of~ 10 in a few seconds, so we
- Reopened V4;
We made sure that P1a (main vacuum pressure) was dropping and before continuing we decided to look back to see what the nominal vacuum state was that we should try to restore.
We are currently searching the two systems for diffrences to see if we can narrow down the culprit of the failure.
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16313
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Thu Sep 2 21:49:03 2021 |
Paco | Summary | Computers | chiara down, vac interlock tripped |
[tega, paco]
We found the files that took excess space in the chiara filesystem (see Attachment 1). They were error files from the summary pages that were ~ 50 GB in size or so located under /home/cds/caltech/users/public_html/detcharsummary/logs/. We manually removed them and then copied the rest of the summary page contents into the main file system drive (this is to preserve the information backup before it gets deleted by the cron job at the end of today) and checked carefully to identify the actual issue for why these files were as large in the first place.
We then copied the /detcharsummary directory from /media/40mBackup into /home/cds to match the two disks. |
Attachment 1: 2021-09-02_21-51-15.png
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Wed Dec 22 14:57:05 2021 |
Koji | Update | General | chiara local backup |
chiara local backup of /cvs/cds has not been running since the move of chiara in Nov 19. The remote backup has not been taken since 2017.
The lack of the local backup was because of the misconfiguration of /etc/fstab.
It was fixed and now the backup disk was mounted. We'll see the backup script running tomorrow morning.
The backup disk is smaller than the main disk. So sooner or later, we will face the backup problem again.
localbackup script was crying because there was no backup disk.
backup>pwd
/opt/rtcds/caltech/c1/scripts/backup
backup>tail localbackup.log
2021-12-18 07:00:02,002 INFO Updating backup image of /cvs/cds
2021-12-18 07:00:02,002 ERROR External drive not mounted!!!
2021-12-19 07:00:01,146 INFO Updating backup image of /cvs/cds
2021-12-19 07:00:01,146 ERROR External drive not mounted!!!
2021-12-20 07:00:01,255 INFO Updating backup image of /cvs/cds
2021-12-20 07:00:01,255 ERROR External drive not mounted!!!
2021-12-21 07:00:01,361 INFO Updating backup image of /cvs/cds
2021-12-21 07:00:01,361 ERROR External drive not mounted!!!
2021-12-22 07:00:01,469 INFO Updating backup image of /cvs/cds
2021-12-22 07:00:01,470 ERROR External drive not mounted!!!
fstab had no entry for the backup disk.
backup>cat /etc/fstab
# /etc/fstab: static file system information.
#
# Use 'blkid -o value -s UUID' to print the universally unique identifier
# for a device; this may be used with UUID= as a more robust way to name
# devices that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point> <type> <options> <dump> <pass>
proc /proc proc nodev,noexec,nosuid 0 0
# / was on /dev/sda1 during installation
UUID=972db769-4020-4b74-b943-9b868c26043a / ext4 errors=remount-ro 0 1
# swap was on /dev/sda5 during installation
UUID=a3f5d977-72d7-47c9-a059-38633d16413e none swap sw 0 0
# OLD BACKUP DISK
#UUID="90a5c98a-22fb-4685-9c17-77ed07a5e000" /media/40mBackup ext4 defaults,relatime,commit=60 0 0
# CURRENT BACKUP DISK as of 2021/09/02
#UUID="1843f813-872b-44ff-9a4e-38b77976e8dc" /media/40mBackup ext4 defaults,relatime,commit=60 0 0
#fb:/frames /frames nfs ro,bg
# CURRENT MAIN DISK as of 2021/09/02
# UUID=92dc7073-bf4d-4c58-8052-63129ff5755b /home/cds ext4 defaults,relatime,commit=60 0 0
UUID="1843f813-872b-44ff-9a4e-38b77976e8dc" /home/cds ext4 defaults,relatime,commit=60 0 0
Checked the dev name of the disks and the UUIDs
backup>sudo lsblk
[sudo] password for controls:
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 465.8G 0 disk
├─sda1 8:1 0 446.9G 0 part /
├─sda2 8:2 0 1K 0 part
└─sda5 8:5 0 18.9G 0 part [SWAP]
sdb 8:16 0 5.5T 0 disk
└─sdb1 8:17 0 5.5T 0 part /home/cds
sdc 8:32 0 3.7T 0 disk
└─sdc1 8:33 0 3.7T 0 part
sr0 11:0 1 1024M 0 rom
backup> sudo blkid
/dev/sda1: UUID="972db769-4020-4b74-b943-9b868c26043a" TYPE="ext4"
/dev/sda5: UUID="a3f5d977-72d7-47c9-a059-38633d16413e" TYPE="swap"
/dev/sdb1: UUID="1843f813-872b-44ff-9a4e-38b77976e8dc" TYPE="ext4"
/dev/sdc1: UUID="92dc7073-bf4d-4c58-8052-63129ff5755b" TYPE="ext4"
Added the fstab entry for the backup disk
media>cat /etc/fstab
# /etc/fstab: static file system information.
#
# Use 'blkid -o value -s UUID' to print the universally unique identifier
# for a device; this may be used with UUID= as a more robust way to name
# devices that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point> <type> <options> <dump> <pass>
proc /proc proc nodev,noexec,nosuid 0 0
# / was on /dev/sda1 during installation
UUID=972db769-4020-4b74-b943-9b868c26043a / ext4 errors=remount-ro 0 1
# swap was on /dev/sda5 during installation
UUID=a3f5d977-72d7-47c9-a059-38633d16413e none swap sw 0 0
# OLD BACKUP DISK
#UUID="90a5c98a-22fb-4685-9c17-77ed07a5e000" /media/40mBackup ext4 defaults,relatime,commit=60 0 0
# OLD BACKUP DISK as of 2021/09/02
#UUID="1843f813-872b-44ff-9a4e-38b77976e8dc" /media/40mBackup ext4 defaults,relatime,commit=60 0 0
# Current backup disk as of 2021/12/22
UUID="92dc7073-bf4d-4c58-8052-63129ff5755b" /media/40mBackup ext4 defaults,relatime,commit=60 0 0
#fb:/frames /frames nfs ro,bg
# CURRENT MAIN DISK as of 2021/09/02
# UUID=92dc7073-bf4d-4c58-8052-63129ff5755b /home/cds ext4 defaults,relatime,commit=60 0 0
UUID="1843f813-872b-44ff-9a4e-38b77976e8dc" /home/cds ext4 defaults,relatime,commit=60 0 0
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Thu Feb 10 21:16:27 2022 |
Koji | Summary | CDS | chiara resolv.conf wierdo |
During the videomux debug, I noticed that the host name resolving on chiara didn't behave well. Basically I could not login to anything from chiara using host names.
I found that there was no /etc/resolv.conf. Instead, there is /etc/resolvconf directory.
According to my research, live resolv.conf is placed in /run/resolveconf/resolv.conf .
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
# DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver 192.168.113.20
nameserver 131.215.125.1
nameserver 8.8.8.8
This 113.20 is directing an old "linux1" machine. Too much obsolete. If I modify this file as
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
# DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver 192.168.113.104
nameserver 131.215.125.1
nameserver 8.8.8.8
search martian
Then the name resolving became reasonable. However, during rebooting / service resetting / etc, resolvconf -u command is executed and /run/resolveconf/resolv.conf is overridden, as indicated in the file.
I have modified /etc/resolvconf/resolv.conf.d/base to include 192.168.113.104 and search martian . The latter was included but the former did not show up.
FInally I figured out that, after the resolv.conf is constructed from base and head files in /etc/resolvconf/resolv.conf.d/ , NetworkManager overrides the nameserver addresses.
The configuration was found in /etc/NetworkManager/system-connections/Wired\ connection\ 1 .
Here is the modified setting (dns entry was modified)
>sudo cat /etc/NetworkManager/system-connections/Wired\ connection\ 1
[sudo] password for controls:
[802-3-ethernet]
duplex=full
mac-address=68:05:CA:36:4E:B4
[connection]
id=Wired connection 1
uuid=ed177e70-d10e-42be-8165-3bf59f8f199d
type=802-3-ethernet
timestamp=1438810765
[ipv6]
method=auto
[ipv4]
method=manual
dns=192.168.113.104;131.215.125.1;8.8.8.8;
addresses1=192.168.113.104;24;192.168.113.2;
And
>cat /etc/resolvconf/resolv.conf.d/base
search martian
# See Also /etc/NetworkManager/system-connections/Wired\ connection\ 1
So complicated...
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Thu May 28 14:34:25 2009 |
rob | Update | PSL | chiller diagnosis |
Quote: |
steve, alberto, rob
After some futzing around with the chiller, we have come to the tentative conclusion that the refrigeration unit is not working. Steve called facilities to try to get them to recharge the refrigerant (R-404a) tomorrow, and we're also calling around for a spare chiller somewhere in the project (without luck so far).
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The repair man thinks it's a bad start capacitor, which is 240uF at 120V. Steve has ordered a new one which should be here tomorrow, and with luck we'll have lasing by tomorrow afternoon. |
4992
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Tue Jul 19 21:05:55 2011 |
haixing | Update | DAQ | choose the right relay |
Rana and I are working on the AA/AI circuit for Cymac. We need relays to bypass certain paths in the circuit, and we just found a nice website
explaining how to choose the right relay:
http:/zone.ni.com/devzone/cda/tut/p/id/2774
This piece of information could be useful for others. |
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Tue Jun 30 23:09:40 2009 |
Alberto | Update | Locking | chronicles of some locking attempts |
Tonight I tried to lock the interferometer. At the first attempts the arm power didn't go above about 4. The mode cleaner seemed to be not well aligned and it lost lock or got stuck on a wrong mode. I had to run the MC_UP and MC_DOWN scripts to lock it again.
After that the locking proceed more smoothly; at least till a power level in the arms of about 60. Then again the mode cleaner lost lock and I had to run the scripts again. Without the MCWFS servo off the MC reflected power is still rather high (about 1.7); also even when the WFS servo is engaged the reflected power is about 0.5, versus 0.3 that it should be.
Those are both signs of a not very good alignment. Tomorrow I'll have to work on the injection periscope on the PSL table to try to fix that. |
12802
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Mon Feb 6 10:05:28 2017 |
Steve | Update | SUS | clamped cables |
The bottom 5 cable connections from Sat-Amp to Whittering Filter at 1X5 were clamped today. |
Attachment 1: clamped.jpg
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7146
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Fri Aug 10 17:17:41 2012 |
Alex Masha Den | Update | PEM | classify seismic c code |
Den and I installed a module in the c1pem model which has a feedforward neural network to classify seismic disturbance (10 means quiet, 20 truck, 30 earthquake). There is a channel SEIS_CLASS which should specify the class of the seismic signal. The code works for signals sampled at 256 Hz, so an anti-aliasing filter must be installed in order to decimate from the 2048 model.
The models were compiling slowly, so Alex removed the archiving feature (gzip and tar were taking a lot of time).
Den and I also had trouble with a simple for loop in our model, so we talked to Alex who noted that the -O3 compiler unravels for loops in a buggy way. Thus, we have compiled c1pem using the -O compiler.
PS: the Trilium seismometer now has legs. |
7147
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Fri Aug 10 17:38:29 2012 |
Den | Update | PEM | classify seismic c code |
Quote: |
Den and I also had trouble with a simple for loop in our model, so we talked to Alex who noted that the -O3 compiler unravels for loops in a buggy way. Thus, we have compiled c1pem using the -O compiler.
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Alex also modified RCG script to generate -O in the Makefile for c1pem model:
controls@pianosa:/opt/rtcds/rtscore/release/src/epics/util 127$ svn diff
feCodeGen.pl
Index: feCodeGen.pl
===================================================================
--- feCodeGen.pl (revision 2999)
+++ feCodeGen.pl (working copy)
@@ -3183,7 +3183,12 @@
print OUTM "\n";
}
print OUTM "ALL \+= user_mmap \$(TARGET_RTL)\n";
+# do not optimize c1pem
+if ($skeleton eq "c1pem") {
+print OUTM "EXTRA_CFLAGS += -O -w -I../../include\n";
+} else {
print OUTM "EXTRA_CFLAGS += -O3 -w -I../../include\n";
+}
print OUTM "EXTRA_CFLAGS += -I/opt/gm/include\n";
print OUTM "EXTRA_CFLAGS += -I/opt/mx/include\n"; |
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Thu Oct 22 08:52:04 2015 |
Steve | Update | VAC | clean RGA scan after sweaty Maglev |
Clean comparable scan at vacuum normal. There was no backstreaming. |
Attachment 1: clean_scan.png
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8004
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Tue Feb 5 15:31:03 2013 |
Steve | Update | General | clean assembly room benches cleaned up |
Manasa, Jamie and Steve,
Tip-Tilts and parts moved into the most north " 40m " cabinet in the assembly room.
Green-black glass and related components were moved to the 40m E0 cabinet in plastic boxes.
The north flow bench has a few items that belong to us: HE/Ne laser, qpd on translation stages, an iris and one red mirror. These were moved to the north edge of this bench.
However this leveled table is still full with other people's stuff |
Attachment 1: IMG_0057.JPG
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Attachment 2: IMG_0061.JPG
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Tue Aug 9 16:40:12 2011 |
steve | Update | General | clean room coat counts |
I measured the particles coming off of new- unused clean room coat. Tyvek, Convertors, Allegiance #9393 measured 10 counts of 0.3 micron at 1 minute and 0 count at 7 minute.
The 0.5 micron size measured 0 at both times. Jenne's used coat measured 20 counts of 0.3 micron and 0 counts for 0.5 micron at 1 minute. ( counts / cf- min)
The HEPA tent background is consistently 0 when it's CP STAT 100 curtains are closed. |
Attachment 1: P1080155.JPG
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Thu Aug 25 17:14:49 2011 |
steve | Update | VAC | clean room fashion changes |
Jamie is modeling our next generation in-vac & clean room bonny suit that Jenne and myself already tested.
It is quite bearable with our traditional cleanroom beret-bouffant cap. Please use these in the future.
This will help to avoid the farther degradation of somewhat dusty 40m vac envelope.
It is the required dress code to enter the clean assembly room in the 40m.
We have small, med, large and x-large in stock. I'm getting larger sizes.
It will not allow certain people to climb inside the vacuum chamber in dirty pants. |
Attachment 1: P1080185.JPG
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Attachment 2: P1080183.JPG
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Tue Mar 8 15:23:16 2011 |
steve | Update | PEM | clean room gloves |
Ansell AccuTech 91-300 clean room gloves ONLY in the 40m lab.
Cleaning and preparation must be carried out in these gloves also. |
3705
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Wed Oct 13 11:09:28 2010 |
yuta | Update | Computers | clean-installed CentOS 5.5 on mafalda |
Dear mafalda,
Sorry for leaving you alone.
We put ethernet cable in you. You can talk to everyone now!
We created a user "controls" correctly. (UID: 1001)
We mounted linux1:/home/cds/ to your directory /cvs/cds.
Truly yours,
Joseph Betzwieser
Yuta Michimura
Quote: |
Quote: |
I clean-installed CentOS 5.5(32bit) on mafalda.
No firewalls, no SELinix.
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Yuta has removed my ethernet connection . Help me!!!
rossa:mDV>ping mafalda
PING mafalda.martian (192.168.113.23) 56(84) bytes of data.
From rossa.martian (192.168.113.215) icmp_seq=2 Destination Host Unreachable
From rossa.martian (192.168.113.215) icmp_seq=3 Destination Host Unreachable
From rossa.martian (192.168.113.215) icmp_seq=4 Destination Host Unreachable
--- mafalda.martian ping statistics ---
5 packets transmitted, 0 received, +3 errors, 100% packet loss, time 3999ms
, pipe 3
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Fri Sep 17 17:35:35 2010 |
steve | Update | PEM | cleaned up at 1Y1 PSL rack |
Cleaned up cables on the top and bottom. Vacuumed both areas. We still have some remaining shading from the MOPA umbilical and more unknown BNC cables hanging around. |
11388
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Wed Jul 1 11:45:48 2015 |
Steve | Update | PEM | cleaning around ETMX chamber |
Quote: |
Keven is our regular janitor is out for a few weeks.
The sub is careful- gentel Mario. We wiped arouind the vertex cambers north side on the floor and east arm racks.
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Mario wiped the floor around the ETMX chamber today. |
11372
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Tue Jun 23 11:18:20 2015 |
Steve | Update | PEM | cleaning around chambers |
Keven is our regular janitor is out for a few weeks.
The sub is careful- gentel Mario. We wiped arouind the vertex cambers north side on the floor and east arm racks.
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9914
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Tue May 6 09:46:50 2014 |
steve | Update | PEM | cleaning day |
Keven and Steve,
We cleaned around the Vertex chambers, PSL and MC2 floor areas.
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Attachment 1: 120d.png
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Thu Jul 7 10:25:34 2011 |
steve | HowTo | General | cleaning out refregerator |
Please ask the owner unless it is rotten. Do not put food into garbage can inside. Take them outside so you are not inviting ants ! |
9092
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Fri Aug 30 14:31:57 2013 |
Steve | Update | General | cleaning up |
I cleaned up around MC2 and 1Y1 area this morning.
ETMY NPRO moved from the side to the center of the low shelf. Thorlab catalog " as spacer " removed after lunch.
The Lightwave Controller values: LT 40.4C, LTEC +0.1V, T 41.041C, Pwr 239 mW, Adj 0, DC 1.82A, DPM 0.0V, Neon OFF, Ldon OFF, Display 5, DT 21.0C, Dtec +1.0V
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Attachment 1: MC2areaCP.jpg
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Attachment 2: 1Y1areaCleanedUp.jpg
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Attachment 3: ETMY_NPROmoved.jpg
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Fri Jun 15 08:09:15 2018 |
Steve | Bureaucracy | General | cleaning up at the PSL enclousure |
The cabeling was cleaned up a little bit yesterday morning. The upper back side is still massy. |
Attachment 1: before.jpg
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Attachment 2: after.jpg
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Attachment 3: back_side.jpg
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Thu Jun 20 09:33:42 2013 |
Steve | Update | General | cleanup |
Office work benches were cleaned up yesterday. Anti-image filter boards were moved to north wall of the control room. Koji's pd- electronics box placed next to water dispenser.
The removed ETMY optical table: TMC 4' x 2' x 4" with Aluminum enclosure was placed on table in the east arm. |
Attachment 1: tmc3x2.jpg
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Wed May 1 10:42:35 2013 |
Steve | Update | LSC | cleanup |
Optics from the car were placed into glass door cabinet E0 |
16796
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Thu Apr 21 16:36:56 2022 |
Tega | Update | VAC | cleanup work for vacuum git repo |
git repo - https://git.ligo.org/40m/vac
Finally incorporated the FRGs into the main modbusIOC service and everything seems to be working fine. I have also removed the old sensors (CC1,CC2,CC3,CC4,PTP1,IG1) from the serial client list and their corresponding EPICS channels. Furthermore, the interlock service python script has been updated so that all occurrence of old sensors (turns out to be only CC1) were replaced by their corresponding new FRG sensor (FRG1) and a redundnacy was also enacted for P1a where the interlock condition is replicated with P1a being replaced with FRG1 because they both sense the main volume pressure. |
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Tue Oct 20 10:46:18 2009 |
steve | Update | IOO | clipping IP-ANG beam at ETMX chamber |
Initial pointing beam is clearly clipping on 2" pick off mirror in ETMX vacuum chamber.
Atm. 1 The pick off mirror is just north west of the ETMX test mass
Atm. 2 The camera is looking in from the north view port of ETMX chamber. The back side of pick off mirror is visible now with the face view of the "IP-ANG-OUT" mirror.
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Attachment 1: PA200175.JPG
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Attachment 2: PA200177.JPG
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Wed Feb 8 10:16:39 2017 |
steve | Update | SUS | clipping ITMX oplev |
The ITMX oplev beam is clipping. It will be corected with locked arm
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Attachment 1: ITMX_oplev_clipping.jpg
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Attachment 2: ITMX_clipping.jpg
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Fri May 18 07:41:01 2018 |
steve | Update | SUS | clipping ITMX oplev |
The ITMX oplev still clipping
Quote: |
The ITMX oplev beam is clipping. It will be corected with locked arm
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6902
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Mon Jul 2 10:45:25 2012 |
Jenne | Summary | General | clipping at BS |
Quote |
No significant change was found inside the vacuum. We still see clipping at the Faraday, and also, we saw clipping by BS coil holder. Using PZT1, we could make it better, but this might be causing PRC problem -- BS is inside the PRC, too.
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Yuta just told Jamie and I that when he and Koji were looking at things yesterday, they saw that the beam spot was roughly at the center of the PRM, but was clipping on the lower OSEM holder plate on the BS. This indicates that the beam spot on the BS is much too low. The easiest way I can see this happening is poor pitch pointing with the tip tilts, which we unfortunately don't have active control over.
Recall elog 3425, where I mentioned some pretty bad pitch pointing after a TT was moved from the cleanroom, to the chamber, back to the cleanroom. I think that we may need to check the pitch pointing at the chamber before installing tip tilts in the future. |
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Sun Jul 1 23:48:15 2012 |
yuta | Summary | General | clipping at BS, my plan |
[Koji, Yuta]
We aligned PRMI and inspected BS chamber. Last inspection by Jamie and I (see elog #6897) was done when nothing is aligned, so I wanted to see the difference.
Aligning PRMI at low power was difficult for me, because I see no fringe at ASDC PD nor REFLDC PD. I just aligned them by looking at AS/REFL camera. The beam shape at AS looked as bad as when the usual power.
No significant change was found inside the vacuum. We still see clipping at the Faraday, and also, we saw clipping by BS coil holder. Using PZT1, we could make it better, but this might be causing PRC problem -- BS is inside the PRC, too.
We also took some pictures of PR3 and PRM(attached). The arrow pointing HR is correctly pointing inside the PRC. Seeing is believing.
Yuta's plan:
We might have to avoid clipping at BS (and Faraday) by aligning input optics inside the vacuum. If we are going to align them, I think we should start from centering MC beam spot positions and the whole alignment could take more than a week. I don't want to spend too much time on the alignment. Also, we are going to install tip-tilts on the next big vent, so we have to redo the alignment anyway.
So, my plan is as follows;
1. Take lots of photos and close the door on Monday(June 2).
2. Pump on Tuesday(June 3).
3. Restart working on ALS. For example, demonstration of FPMI using ALS.
4. We also can do some characterization of PRC, like measuring power recycling gain for PRMI/PRFPMI, mode scan for PRC using AUX laser from AS port, and so on. We need some calculation for clipping tolerance, too.
Any objections? |
Attachment 1: PR3.JPG
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Attachment 2: PRM.JPG
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Mon Jul 2 00:41:13 2012 |
rana | Summary | General | clipping at BS, my plan |
Start pumping on Monday before Steve goes home. |
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Wed Feb 20 03:13:10 2013 |
yuta | Update | Alignment | clipping centering checklist |
I attached clipping/centering checklist for the alignment.
Blue ones are the ones we checked today. Red ones should be checked tomorrow. Circles indicate centering on the optics, rectangles indicate clipping check, and arrows indicate retro-reflecting or bounces.
We found mis-centering on MMT1, PR2 and SR3 tonight (by ~0.5 beam diameter). They are also indicated.
I think we don't want to touch MMT1 and PR2 anymore, because they change input beam pointing.
I'm a little bit concerned about high beam on SR3, because we had PRC flashing in vertical higher order modes. We also see ETMX slider values high in pitch (~ 5.4).
Also, the diameter of ETMX reflected beam on ITMX looked larger and dimmer than ITMX transmitted beam, which doesn't seem reasonable.
Wednesday, Feb 20:
- tweak TT1/TT2 and PRM so PRC flashes
- re-check Yarm/Xarm bounces
- center beam on all AS optics, starting from SR2
- make sure REFL and AS is clear
- check if TRY/TRX are coming out from the ends
- check beam centering on mirrors in IMC/OMC chamber as far as you can reach
- inject green from both ends
- make sure green beams are not clipped by mirrors on BS chamber, IMC/OMC chamber
- re-center all oplevs, with no clipping
- check all OSEM values
- take pictures of flipped PR2 and input TTs (and everything)
- close all heavy doors and put the access connector back
Thursday, Feb 21:
- make sure we can lock PRMI
- start pumping down when Steve arrives |
Attachment 1: ClippingCenteringChecklist.pdf
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Wed Feb 20 20:58:37 2013 |
yuta | Update | Alignment | clipping centering checklist |
Blue ones are the ones we checked yesterday.
Green ones are the ones we checked today.
Red ones are the ones we couldn't check.
We noticed mis-centering on green optics and partial clipping of higher order modes, but we did not touch any green optics in-vac. This is because green beam from Y end and X end has different spot positions on the green optics after periscopes. We confirmed that direct green beam from ends are not clipped.
I believe we have checked everything important. Any other concerns?
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Attachment 1: ClippingCenteringChecklist.pdf
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