Tonight was mostly cleaning up some scripts, including the re-writing the restore and align scripts for the optics.
The new script is in the same folder as the old one (/opt/rtcds/caltech/c1/medm/MISC/ifoalign/NewAlignSoft.py), but is not yet called from the align screen. However, I'm using it in the carm up and down scripts, and it works nicely for the PRM. I need to check that the offset value is okay for all the other optics (i.e. are they getting misaligned enough?), but then I'll have the new script called from the screen. The new script, per Rana's suggestion, does not touch the bias sliders. Rather, it puts an offset in the pitch filter banks in the coil driver output matrix-of-filter-banks. Then the misalign routine turns the offset on, and the restore routine turns the offset off. This way we have a nice ramp time, but don't have to do the weird calculation of number of steps to take as is done in the current script. Also, the "save" functionality will be obsolete, since we're never touching the bias sliders except for actual alignment needs.
I'm not sure what changed, other than the HEPA being on lower, but the Xarm ALS was much better behaved tonight. I was able to hang out around arm powers of ~1 for as long as I wanted.
I didn't try to hand over to digital REFLDC, but I was trying a few times to engage the AO path. With the CM board set to Plus, I hear hooting when MC IN2 is about 4dB. With the CM board set to Minus, I didn't hear hooting, but I lost lock when I went from 13dB to 14dB.
Also, I put the cables for the SR785 back to the "A" set of test points and excitation, so that I could take a closed loop transfer function. However, I don't know where the latest working scripts to make a remote measurement are, so maybe we can take some loop measurements tomorrow.
The carm_cm_up script is good (for tonight) up to the prompt "Press enter to indicate that it is okay to turn on MC2 LSC FM8". There are "read"s every step of the way, so it goes nice and slow, but it'll do everything for you except any last tweaks of the PRM alignment after the PRMI is locked.
It's starting to get a little crowded, but I modified the IFO_ALIGN screen to have new buttons to show the aligned / misaligned state of each optic. Koji made a good point, and I left the old restore script functional so that if the slider is moved significantly, we can always go back gently to the burt restored value. I have removed the old misalign function though, since we shouldn't ever be using that again.
I tried many times this evening to engage the AO path, with limited success.
Q's new scripts worked really well, and so I have some transfer functions! To take these measurements, in ...../scripts/general/netgpib, I am running ./TFSR785 TFSR785_CARMloop_May2014.yml, where the file name is the name of my parameter file. The data, and the saved pdfs, are in /users/jenne/PRFPMI/CARM_loop_measurements/2014May14/ . For these measurements, the SR785 is hooked up to the "A" set of excitation and test points on the CM board.
All of these traces were taken while the IFO was PRFPMI, with PRCL and MICH on REFL33, DARM on ALS diff, and CARM on InvSqrtTrans. carm_cm_up.sh is up to date, through the echo "REFL_I should now be zero" (~line 111 in the script). All you need to do is set the beatnotes, and then run the script. Follow instructions in the prompt (such as "press enter to confirm PRMI is locked").
Here are my notes for the various times:
23:01:44 - MC IN2 = 0dB, CARM gain = 5.0
23:13:45 - MC IN2 = 10dB, CARM gain = 5
23:26:10 - MC IN2 = 6dB, CARM gain = 10 (after Q suggested increasing overall gain, rather than just AO path)
00:13:07 - MC IN2 = 6dB?, CARM = 6ish? don't remember exactly.
00:45:00ish, Realigned IFO using IR with arms.
01:03:17 - MC In2 = 0dB, CARM gain = 5
01:07:42 - MC IN2 = 8dB, CARM gain = 6.295 (AO went up to 6dB, then +1dB steps to both simultaneously using ezcastep C1:LSC-CARM_GAIN 1dB C1:IOO-MC_AO_GAIN 1)
ezcastep C1:LSC-CARM_GAIN 1dB C1:IOO-MC_AO_GAIN 1
01:08:57 - MC IN2 = 10dB, CARM gain = 7.92447
01:10:08 - MC IN2 = 12dB, CARM gain = 9.97631
lockloss when trying to add 1 more dB to both.
01:41:36 - MC IN2 = 12dB, CARM gain = 9.97
lockloss when just MC IN2 up by 1dB, left CARM gain alone.
The 60Hz noise in TRY is back. Since I thought I remembered someone suggesting that it was leakage light from the exit sign, Koji went in and wrapped the end table in foil, however the lines are still present.
In addition to a transparent legend, we need the corresponding CM crossover measurements from DTT to compare with the Q-Mist-Loop model results. The xover tells us when the AO gain is high enough so that they can be ramped up together.
Also, I wonder how much power fluctuation we get from the large ALS DIFF noise and if that demands we get the TR signals normalized by POPDC.
We have looked at a few things that do and don't affect the out of loop noise of the ALS X beat, and found that cavity alignment and beatnote RF frequency had the strongest effects.
Possible causes of noise:
1. Air currents from A/C or flowbench. No effect.
* When table lid is on, turning on and off the flow bench air did not qualitatively change the out of loop beatnote time series signal.
2. Scattered light from other beams hitting green PDH PD. No effect.
* There are a few spots of green light that are hitting the case of the PDH photodiode, but when I put an iris in place to block those spots, there was no change in the beatnote spectra. This makes sense to me since none of those spots were close to hitting the diode itself.
* Rana did notice that the beam was not well centered on the PD, so he steered the beam onto the center of the diode. Also, the PD is now tilted a little bit so that the reflection from the diode doesn't go back into the beam path. Neither of these things had an effect that we noticed in the beatnote noise.
3. Oplev laser light getting to PDH PD. Not tested.
* We don't see any red light over by the PDH PD, so we did not try turning off the oplev's laser to see if that had an effect, but we suspect that it is not the cause of our noise.
4. Clipping of main IR / green beam on Xend table. Not tested.
* We should still go have a look at this, but we no longer think that this is the main cause of the elevated noise.
5. Scattered light all over Xend table. Not tested.
* We should still work on dumping extraneous beams on the table, but we do not think that this is the main cause of the elevated noise.
* Rana took some photos so that we can see how truely bad the situation is.
6. Amplitude modulation dip in NPRO. Not tested.
* It is probably still a good idea to check this, in case the dip in the amplitude modulation has changed over the year or two since it was last measured, but we also don't think that this is the main problem.
7. Check PDH servo. Not done.
* I think this is still on Q's long-term todo list, but we should give the PDH servos a once-over.
8. Arm cavity longitudinal motion. No effect.
* While the Xarm was locked with IR, we put a line at 1.7 Hz with 325 counts into the ITMX position. To keep lock, the ETM had to move as well. When we turned on this line (and increased its amplitude up to the final value of 325 cts), we did not see any qualitative change in the beatnote time series noise.
9. Arm cavity alignment. Significant DC effect.
* When the alignment of one of the arm cavity mirrors is changed, the DC value of the beatnote signal changes.
* ITMX moved in yaw, we see a 7kHz/15urad DC shift in the BEATX_FINE_PHASE_OUT_HZ time series.
* ETMX moved in yaw, we see an 8kHz/5.5urad DC shift in the time series. We aren't sure why this is about a factor of 3 times larger effect (same shift for smaller misalignment) than the ITM.
* We want to do a Yuta-style analysis to see what the angle to length coupling looks like, so that we can measure the angular motion of our cavity mirrors and put the expected noise into our ALS noise budget. Perhaps this will help us understand the low frequency difference between our in-loop beatnote error signal and our in-loop PDH error signals (red vs. maroon on the ALS noise budget posted above Pianosa).
* I've asked Manasa to take some transfer functions in the morning, so that we can start to have an idea of what is going on with this.
10. Beatnote RF frequency. Significant broadband effect.
* We have found that when the Xarm beatnote is at low RF frequencies, the noise is high, and when the beatnote is at high RF frequencies, the noise is low!
* Low RF freqs are below about 40 MHz, while high RF freqs are above about 90 MHz. This has not been tested for the Yarm. Also, these are for the case of "temp slider up, beatnote up". I have not checked if the same is true for the other side of the PSL frequency, although I don't have reason to believe that it would be.
* Maybe we are saturating some amplifiers? We need to check this out. One thought that Den mentioned was the harmonics, and that perhaps they are causing trouble in the electronics.
* Den is going to think about implementing a frequency divider so that we can directly digitize the beatnote signal.
* Here are spectra for different cases:
* And here is a spectrogram showing us going back and forth between the high and low noise states:
* A: First noticing that noise is good when RF frequency is high.
* B: Not locked on TEM00 mode, so extra noisy. Disregard.
* C: Bad noise time. Xbeat was 21 MHz (dark purple on DTT spectrum above), Ybeat was 118 MHz (sea green on DTT spectrum above).
* D: Good noise time. Xbeat was 89 MHz (light purple on DTT plot), Ybeat was still 118MHz (turquoise on DTT plot).
* E: Bad noise time. Xbeat was 37.5 MHz, Ybeat was still 118 MHz.
* F: Good noise time. Xbeat was 113 MHz, Ybeat was still 118 MHz.
Since Q has found that REFL165 will be better for holding the PRMI while we reduce the CARM offset, I had a look at locking PRMI sideband locking with both 3f PDs.
I checked the REFL165 demod phase, and changed it from -142.5 deg to -138.5 deg. to minimize the Q signal while driving PRM length.
I found that keeping the MICH and PRCL loop gains the same, and using matrix elements +0.1 for both I and Q for REFL165, rather than +1 for both I and Q for REFL 33.
MICH gain is +0.8, PRCL gain is -0.02. FMs 4,5 on for both, FM 2 triggered for MICH, FMs 2,3,6 triggered for PRCL.
I then locked the PRMI on sideband with REFL 33 and then REFL 165, and measured the other one as an out of loop sensor of the motion. I find that REFL33 and 165 are both comparable, and so we shouldn't have any trouble using REFL165 for locking.
We spent some time tonight looking at locking the PRMI with REFL165 vs. REFL33, while reducing the CARM offset.
We were not able to lock the PRMI on REFL165 I&Q at small CARM offsets. When locking at larger CARM offsets (about 100 counts, which is about 100nm) and then re-adjusting the REFL165 demod phase as I reduced the CARM offset, I saw that I had to significantly rotate the phase. For PRMI only (no arms), the REFL165 demod phase was -138.5 deg. When the PRMI was locked with a -100 count CARM offset, the optimal demod phase was -123 deg. Then at -90 counts the phase was -113 deg. At -70 counts, the phase was -108 deg, at -50 counts it was -98 deg, and at -40 it was -93 deg. We want to go back and look at these more carefully, and in a more continuous way, by watching the sensing matrix calibration lines. It's unclear to me right now why we're seeing this, but it's possible that we're getting some kind of extra 55MHz resonances.
REFL DC looks like it should be good - same slope and gain as sqrtTR, extra 20 or 30 deg of phase margin, so we think that we should be able to transition over to it, and then try engaging the AO path. Tonight we had Den's new 1kHz lowpass engaged, and with this, everything looks nice and stable.
Game plan: Bring CARM in until transmissions are at about 10ish, then try keeping CARM on sqrtInvTrans for the DC part, and engage the AC AO part with REFL DC. We probably just need to try this for a while more to find just the right way to turn it on.
Need to think about demod phase rotation vs CARM offset as well as extra resonances, but this may take a while, and if we can just get the AO path engaged, that would be good.
I just realized that I forgot to elog this, but yesterday afternoon I bypassed the amplifier in the BeatX path, and now the X beatnote is about -27dBm. Arms lock nicely with ALS.
Sorry, I had been in a hurry when I worked on this last week, and again when I wrote the elog, but I wanted to at least put in a note for any weekend workers.
The ALS beatnote setups need alignment on the PSL table. However, even at very low RF beat frequency, the X beatnote now at low frequencies matches our best measurement from last week. The "HEPA off" (teal and purple) measurements are from last week, and the red and blue are from this week. The X beatnote was 10MHz and the Y beatnote today was 31MHz.
Grr. I am very frustrated. After lunch I redid alignment for both X and Y green systems (Yarm both at the end and on the PSL table, Xarm just on the PSL table). After that realignment work, I cannot find a beatnote for the Xarm!!!
The Ybeat, after aligment, was up to -5.5 dBm when the beat was at 11 MHz. Last week it was something like -20 dBm, so alignment makes a big difference. After doing IR alignment I had noticed that the green transmitted through the Yarm didn't look very bright on the camera, and the power was around 0.2, so I went to the Yend and gently touched the green input steering mirrors, and got the Ygreen trans PD back to more than 0.9 with the PSL green shutter closed. Awesome. Then I touched up the Ygreen PSL alignment, and then saw that the beatnote was nice and large. Hooray. I measured the out of loop noise, and it was even better than the best we saw last week: (greenish was best last week for Yarm, teal blue is new Ygreen):
At this point, I still hadn't touched anything on the X path (except the PZT input steering mirrors, remotely from the control room). The beatnote was about the same size as it was on Friday, around -27dBm. I went onto the PSL table and did the same alignment procedure that I had just done for the Yarm: Remove the green trans PD and the accompanying lens so that I get far-field spots on the wall, and then steer the PSL green and the X green spots until they are nicely overlapped at both the camera (near-field) and on the wall. I looked at the DC output of the beat PD, and centered the beam on the diode. I put back the thorlabs DC transmission PD and the lens, and centered the beam on that. However, after this work, I cannot find a beatnote for the X arm! I still see the nice big Ygreen beatnote, and I have the PSL and Xend temperatures where they usually are ( abs(FSS Slow) < 0.1, and X end Slow around 10,090. ) I scanned -10,000 counts, and +5,000 counts from there, and still don't find a beatnote!
I went back inside, and I don't see an RF signal coming into the beatbox from the Xarm. It's not the cable's fault though, since I then hooked the RF output of the beat PD to a 'scope, and still didn't see any beatnote. The DC path of the PD is definitely seeing things, because when I switch the 'scope over to the DC output of the Xbeat PD, and I block/unblock the beam, I see the voltage step up and down as expected.
I have not pulled out the Xgreen broadband PD, but unless someone else has a good idea of what to check, that might be one of the next things to do.
Ideas of things I could try:
* Put the X broadband PD on the Y beatnote path to see if I see the same Y beatnote (use the port where the Y green trans PD is, since it has the coaligned beams, and a lens).
* Open the PD and see if anything on the RF path is fried.
* Move the Y PD over to the X path, to see if it sees the beatnote.
Also, while I was working on the PSL table, I heard noise that sounded like a bearing rolling around. I suspected the HEPAs, since the one on the north east corner of the table has a problem when it's turned up high (we've known about this for a long time), however turning off the HEPAs didn't affect the noise. The noise is strongest near the back of the PSL controller on the shelf above the table, and the PSL controller box is vibrating. So, I suspect that the fan on the PSL controller box is about to give out.
EDIT: To clarify, I mean the Innolight's controller.
Current computer status:
All fast machines except c1iscey are up and running. I can't ssh to c1iscey, so I'll need to go down to the end station and have a look-see. On the c1lsc machine, neither the c1oaf nor the c1cal models are running (but for the oaf model, we know that this is because we need to revert the blrms block changes to some earlier version, see Jamie's elog 9911).
Daqd process is running on framebuilder. However, when I try to open dataviewer, I get the popup error saying "Can't connect to rb", as well as an error in the terminal window that said something like "Error getting chan info".
Slow machines c1psl, c1auxex and c1auxey are not running (can't telnet to them, and white boxes on related medm screens for slow channels). All other slow machines seem to be running, however nothing has been done to them to point them at the new location of the shared hard drive, so their status isn't ready to green-light yet.
Things that we did on Friday for the fast machines:
The shared hard drive is "physically" on Chiara, at /home/cds/. Links are in place so that it looks like it's at the same place that it used to be: /opt/rtcds/......
The first nameserver on all of the workstation machines inside of the file /etc/resolv.conf has been changed to be 192.168.113.104, which is Chiara's IP address (it used to be 192.168.113.20, which was linux1). This change has also been made on the framebuilder, and in the framebuilder's /diskless/root/etc/resolv.conf file, which is what all of the fast front ends look to.
On the framebuilder, and in the /diskless place for the fast front ends, presumably we must have changed something to point at the new location for the shared drive, but I don't remember how we did that [ERIC, what did we do???]
The slow front ends that we have tried changing have not worked out.
First, we tried plugging a keyboard and monitor into c1auxey. When we key the crate to reboot the machine, we get some error message about a "disk A drive error", but then it goes on to prompt pushing F1 for something, and F2 for entering setup. No matter what we press, nothing happens. c1auxey is still not running.
We were able to telnet into c1auxex, c1psl, and c1iool0. On each of those machines, at the prompt, we used the command "bootChange". This initially gives us a series of:
$ telnet c1susaux
Connected to c1susaux.
Escape character is '^]'.
c1susaux > bootChange
'.' = clear field; '-' = go to previous field; ^D = quit
boot device : ei
processor number : 0
host name : linux1
file name : /cvs/cds/vw/mv162-262-16M/vxWorks
inet on ethernet (e) : 192.168.113.55:ffffff00
inet on backplane (b):
host inet (h) : 192.168.113.20
gateway inet (g) :
user (u) : controls
ftp password (pw) (blank = use rsh):
flags (f) : 0x0
target name (tn) : c1susaux
startup script (s) : /cvs/cds/caltech/target/c1susaux/startup.cmd
other (o) :
value = 0 = 0x0
If we go through that again (it comes up line-by-line, and you must press Enter to go to the next line) and put a period a the end of the Host Name line, and the Host Inet (h) line, they will come up blank the next time around. So, the next time you run bootChange, you can type "chiara" for the host name, and "192.168.113.104" for the "host inet (h)". If you run bootChange one more time, you'll see that the new things are in there, so that's good.
However, when we then try to reboot the computer, I think the machines weren't coming back after this point. (Unfortunately, this is one of those things that I should have elogged back on Friday, since I don't remember precisely). Certainly whatever the effect was, it wasn't what I wanted, and I left with the machines that I had tried rebooting, not running.
Rana and I now seem to have the fast front end computers (c1lsc, c1sus, c1ioo, c1iscex and c1iscey) up and running! Hooray!
It seemed that we needed to change the soft links back to hard links for rtcds and rtapps on the front end machines. On c1ioo, we did:
sudo rm -rf rtcds
sudo rm -rf rtapps
sudo mkdir rtcds
sudo mkdir rtapps
sudo chown controls:1001 rtcds
sudo chown controls:1001 rtapps
At this time, the front end fstab had several other options in addition to "nolock" for both rtcds and rtapps. They had rw,bg,user,nolock. This state still had some permissions problems. (Later, we have decided that perhaps our next step was unneccesary, since it still left us with (fewer) permissions problems. Taking out the rw,bg,user options from the front end fstab seems to have fixed all permissions issues, so maybe this next chmod step didn't need to be done. But it was done, so I record it for completeness).
On chiara, we did:
sudo chmod -R 777 *
Then on c1iscex, I didn't have to deal with the soft links, but I did need to mount the rtcds and rtapps directories so that I could see files in them. I just did the last 2 operations from the c1ioo list above (mount /opt/rtcds and mount /opt/rtapps).
Since we were still seeing some (fewer) permissions problems, we took out the extra options in the front ends' fstab that Rana had added. Rebooting c1iscex after this, everything came back as expected. Nice!
I think that, at this point, remotely rebooting (sudo shutdown -r now) the other front ends made everything come back nicely. Since we had gotten the fstab situation correct, we didn't have to by-hand mount any directories, and all of the models restarted on their own. Finally!
For posterity, here are things that we'll want to remember:
Frame builder's fstab, in /etc/fstab (only the uncommented lines, since there are lots of comments):
/dev/sdb1 / ext3 noatime 0 1
/swapfile none swap sw 0 0
shm /dev/shm tmpfs nodev,nosuid,noexec 0 0
/dev/sda1 /frames ext3 noatime 0 0
192.168.113.104:/home/cds/ /cvs/cds nfs _netdev,auto,rw,bg,soft 0 0
192.168.113.104:/home/cds/rtcds /opt/rtcds nfs _netdev,auto,rw,bg,soft 0 0
192.168.113.104:/home/cds/rtapps /opt/rtapps nfs _netdev,auto,rw,bg,soft 0 0
Fast front end fstabs, which are on the framebuilder in /diskless/root/etc/fstab:
master:/diskless/root / nfs sync,hard,intr,rw,nolock,rsize=8192,wsize=8192 0 0
master:/usr /usr nfs sync,hard,intr,ro,nolock,rsize=8192,wsize=8192 0 0
master:/home /home nfs sync,hard,intr,rw,nolock,rsize=8192,wsize=8192 0 0
none /proc proc defaults 0 0
none /var/log tmpfs size=100m,rw 0 0
none /var/lib/init.d tmpfs size=100m,rw 0 0
none /dev/pts devpts rw,nosuid,noexec,relatime,gid=5,mode=620 0 0
none /sys sysfs defaults 0 0
master:/opt /opt nfs async,hard,intr,rw,nolock 0 0
192.168.113.104:/home/cds/rtcds /opt/rtcds nfs nolock 0 0
192.168.113.104:/home/cds/rtapps /opt/rtapps nfs nolock 0 0
Rana mentioned this in his elog entry re: SLOW computer recovery, but I want to highlight it:
We cannot yet lock the mode cleaner.
It seems that we need to be aware of the sticky slider issue that we have seen for years (although don't deal with too often) that a burt restore will make it seem like an EPICS channel is at some value, but in fact it is at some other value. For any sliders or buttons in question, change the value by some amount, and then change it back. This forces things to refresh, and it'll then be at the value that is reported.
However, for the MC board, this seems to not be enough. Changing the offset slider doesn't seem to actually change the offset value. The fast output of the MC board is railed at 9.996 V. So. We need to check out the MC servo board and ensure that we are actually connected and talking to it through the c1iool0 (C1i-oh-oh-L-zero, to make the characters more clear) slow machine.
I have brought back c1auxex and c1auxey. Hopefully this elog will have some more details to add to Rana's elog 10015, so that in the end, we have the whole process documented.
The old Dell computer was already in a Minicom session, so I didn't have to start that up - hopefully it's just as easy as opening the program. (Edit, JCD, 9July2014: Startup a terminal session, and then type "minicom" and press enter to get a Minicom session).
I plugged the DB9-RJ45 cable into the top of the RJ45 jacks on the computers. Since the aux end station computers hadn't had their bootChanges done yet, the prompt was "VxWorks Boot". For a computer that was already configured, for example the psl machine, the prompt was "c1psl", the name of the machine. So, the indication that work needs to be done is either you get the Boot prompt, or the computer starts to hang while it's trying to load the operating system (since it's not where the computer expects it to be). If the computer is hanging, key the crate again to power cycle it. When it gets to the countdown that says "press any key to enter manual boot" or something like that, push some key. This will get you to the "VxWorks Boot" prompt.
Once you have this prompt, press "?" to get the boot help menu. Press "p" to print the current boot parameters (the same list of things that you see with the bootChange command when you telnet in). Press "c" to go line-by-line through the parameters with the option to change parameters. I discovered that you can just type what you want the parameter to be next to the old value, and that will change the value. (ex. "host name : linux1 chiara" will change the host name from the old value of linux1 to the new value that you just typed of chiara).
After changing the appropriate parameters (as with all the other slow computers, just the [host name] and the [host inet] parameters needed changing), key the crate one more time and let it boot. It should boot successfully, and when it has finished and given you the name for the prompt (ex. c1auxex), you can just pull out the RJ45 end of the cable from the computer, and move on to the next one.
ETMX had default 1's for gains, 0's for matrix elements, etc., so I did a burt restore to May 25th, 2pm, which was a few days before the Crash. It looks fine now.
We have (now) in the lab 2 cables that are RJ45-DB9. The gray one is LIGO-made, while the blue one is store-bought.
The gray LIGO-made one works, but the blue store-bought one does not. I checked their pinouts, and they are completely different. On the sketch below, the pictures of the connectors is me looking at them face-on, with the cables going out the back of the page. The DB9 is female.
Today, Rossa has been hanging at bootup. You get the desktop, and most of the gui things, and can move the mouse pointer around, but clicking the mouse or using the keyboard have no effect. Once you try clicking something, the mouse pointer turns into the spinning ball, and stays like that.
If, upon rebooting (soft rebooting from another machine, through an ssh session), you hold down the Shift key, you should get to a Grub menu. If you arrow-key down and select the next-most-recent version (not the recovery mode, but just the regular earlier version), and press Enter, Rossa starts up nice and happily.
I am not sure how to make Rossa always boot into this version of things, or how to get rid of the newest version so that the version that works is the most recent, but I'm hoping one of my Linux buddies will help me out on this one. I think (maybe) that I need to find out what package was recently updated and could have caused problems, and then revert that one package. (I think I can look at tail /var/log/apt/history.log to tell me what has recently been updated).
MC autolocker is running. The trouble was with caput and caget and cavput on Pianosa. Rana has switched those lines in mcup and mcdown over to ezcaread and ezcawrites, and that seems to have fixed things. For the MC2tickleON and -OFF scripts, we left the caput and caget and cavput, and saw that they do run successfully on Ottavia. (We tried testing again on Pianosa, and now it seems to be okay with cavput, but we promise it was hanging up on this earlier this evening.) Anyhow, it's all a bit confusing, but it seems to be running fine now.
The autolocker is now running on Ottavia, and Rana is putting it into Ottavia's cronjob list, and commented it out on op340m.
We have removed the option "all_squash" from /etc/exports on Chiara (both lines). We then checked that the files have ownership "controls controls" on Chiara, Pianosa and Rossa. Ottavia still has ownership of "nobody nogroup", so we still need to figure that out.
FSS slow loop:
We confirmed that the slow loop is running. Also, since caput and caget seem to take a while, and the real PID integral gain is the value that we set times a sampling rate, the effective gain had changed. So, Rana compensated by changing C1:PSL-FSS_SLOWKI from 0.03 to 0.1.
Do we have an autoburt saver on another computer, in addition to op340m? (It's in the op340m crontab list) We really only want one of these at a time.
I noticed today, and Rana said that he saw Saturday, that the MC refl value when the MC is unlocked is unusually high. It typically goes to about 4.5 V, but now is going up to 6.5V. Since the PMC output is the same as usual (max seen has been about 0.82 today), something must have happened between the PMC and the IMC.
Late last week, EricG and Nichin were looking at things on the AS table. Was anything touched on the AS table? Was anything touched on the PSL table? 'Fess up please, so that we can pinpoint what the change was.
Also, this afternoon, I touched up the MC alignment a bit, although it still needs work (I've asked Manasa to look at it tomorrow). Rana centered the WFS to my MC alignment (this will need to be redone after the MC is truely aligned), and we turned the WFS on. I also locked both arms individually, and locked MICH and PRMI sideband. The PRMI wasn't especially stable unless I turned on the POP ASC. I assume (hope) that this is just because I was doing it during the day, and not because there is something actually different about the PRMI since the computer meltdown.
Rana and I also took some notes on things that need to be done, starting tomorrow (the first line and the yellow line are scribbles):
PRMI locking with REFL33 is fine. As it was yesterday, it's a little wobbly without the ASC (just PRM oplev), but I don't know that it's any different than it used to be. It'll hold for long periods of time, so I feel okay about it.
When the PRMI is locked, you can push the "up" button on the ASC screen, and it'll turn down the PRM oplev gain by a large factor, and engage the ASC. When you lose lock, press the "down" button to undo these changes. (Probably the ifoconfig script should include the ASC down script). These up and down scripts for the ASC are already included in the carm_up script (the ASC up), and the watch scripts which run a down script (including ASC down) for the whole IFO when ALS loses lock. If the ASC is engaged, I get bored of watching it before the PRMi loses lock on its own, so I think it's okay. (Let's say that means I've watched it stay locked for at least a few tens of seconds, but it looks like it always has with the ASC - like it'll stay forever).
The only thing that seems different about the PRMI is that I've increased the PRCL gain from -0.02 to -0.04. This is a value that it was at some weeks ago, and then we turned it down for loop osc reasons, but now it doesn't want to catch lock with the lower value, and if I turn it down after it's locked, it has trouble holding on. I have included this change into the PRMI sideband configure script.
I haven't tried anything creative like locking with REFL 165. I also didn't lock with 11 or 55, since 33 just worked.
The MC autolocker is once again running on Ottavia, with the nohup command.
It was hanging for a long time (at least minutes) on the cavput and the caputs in the MC2 tickle on and off scripts. I claim that there isn't a good reason to not just use ezcawrite, or whatever the latest and greatest fully functioning function is, so I've changed the cavput to a series of ezcawrites, and all of the caputs are also ezcawrites. Now I don't see any hanging, and the MC locks itself.
This does not solve the scripto_cron issue, so if Ottavia is rebooted, or the autolocker is otherwise killed, it will not start itself up.
I have modified the /etc/default/grub file, so that we're loading up the previous linux kernel version on reboot. Now Rossa boots up (at least one time so far) without any fancy button-pushing.
(Note, if things go south again, we have to push "shift" starting after the Dell screen is gone. Holding it down while the Dell screen is still up doesn't seem to make it register that you want the grub menu).
The grub file USED to look like:
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
but now it looks like:
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
Note that the first line, GRUB_DEFAULT has changed from 0 (first item in grub menu, if you successfully hit shift and get to it) to 2 (the third item in the list). I think that the GRUB_HIDDEN_TIMEOUT_QUIET=false is supposed to force it to show the countdown time when you can push shift, but I didn't see any difference there.
To edit this file, you must use "sudo [text editor] grub". I like emacs, so I used "sudo emacs grub". After an edit, before a reboot, you must run "sudo update-grub". Then you can reboot (sudo shutdown -r now is what I use), and hopefully it will boot as you directed.
sudo [text editor] grub
sudo emacs grub
sudo shutdown -r now
Right now, the 0th (first) entry in the grub menu is "Ubuntu, with Linux 2.6.32-61-generic". The 2nd (third) entry is "Ubuntu, with Linux 2.6.32-58-generic". If we install a new kernel version, the 61 version will bump down in the list, and we'll be booting that, which I assume will fail. We should not update Rossa until we're ready to go to Ubuntu 12, and when we do, we must ensure that the grub file first line reads GRUB_DEFAULT=0. (As a side note, the 1st (really 2nd) entry in the grub menu is "Ubuntu, with Linux 2.6.32-61-generic (recovery mode)", which we don't want. The 58 version has a recovery mode as the next line item, since it alternates version-N, version-N recovery mode, version-(N-1), version-(N-1) recovery mode, etc.)
Arms locked in comm and diff with ALS. PRMI locked with REFL33 I&Q while arms off resonance. Having trouble reducing CARM offset, even to get to arm powers of 1.
After Manasa installed the new Xgreen PD, Koji looked at the PSL table alignment with me. I saw only a very weak beatnote with the X BBPD, even though I could see the beatnote on the Y PD from the leakage of the X beam to the Y PD (Yend shutter was closed, so just PSL and X greens were on the table). I had thought that my near-field and far-field alignments were pretty good (actually, I checked them, but didn't feel that I needed to tweak them since Manasa did the alignment this afternoon). Anyhow, it was just a matter of tweaking up the alignment a bit, and then the X beatnote got up to about -25dBm at a few tens of MHz. I am starting to question myself if the other BBPD is broken, or if I just not well enough aligned. Anyhow, the spare is in, we can still have a look at the previous X BBPD, but it may be okay, and it's just me embarrassing myself by not catching an alignment problem.
Anyhow, after the X beat was found, I was able to (on my first try) lock the arms using ALS comm and diff. (I already had a nice strong Y beatnote, so that didn't need finding, other than temp adjustment of the end laser). I ran the carm_cm_up.sh script, and it did everything nicely. I did a quickie check of the phase tracker loop gains, but that should be redone in the morning.
PRMI was a little reluctant to lock, so I played around with the MICH and PRCL gains, but didn't really find any combination that was any better than the usual (+0.8 for MICH, -0.04 for PRCL as I had last night, although I needed to reduce the PRCL gain back to -0.02 to eliminate loop osc).
After an arm lockloss, I relocked just the PRMI and used awggui to put a line into C1:LSC-PRM_EXC to check the RF PD phasing. I changed REFL33 from 133.5 to 138.5, and REFL 165 from -142.5 to -152.5. I didn't think that REFL11 needed changing, and I didn't check REFL55. I also checked that I could lock PRMI without arms, using both REFL33 and REFL165 - they seemed about the same to me, both stable. REFL33 has 1's in the input matrix, and I was using 0.07's for REFL165. The demod phase adjustment didn't really improve PRMI locking while the arms were held off resonance, even if I moved the arms even farther from resonance (usually we do 3nm, I went out to 5nm to see if that helped - it didn't). I tried REFL165 locking, but that wasn't any good either. I tried using REFL165 with the arms held off resonance, but that didn't seem to catch at all (at least with REFL33 I was getting short lock blips).
Anyhow, of the 3 or 4 times that I caught REFL33 PRMI lock and tried to reduce the CARM offset, only one time did I even get to arm powers of about 1 (CARM digital offset of -0.1, with CARM held on sqrt transmission signals), and then it didn't stay for more than a few tens of seconds. The other few times, it broke lock on the way up to arm powers of 1.
So, carm_cm_up.sh works pretty well, although perhaps the arm powers of 1 offset reduction needs to be a little slower. PRMI doesn't catch and hold lock very easily with REFL33, and even less so with REFL165. It may be useful to try catching lock with REFL11 or 55, and doing a transition over to 3f. No real progress forward, but we're pretty much recovered.
Still no real luck getting the beam back aligned to the IFO.
Koji and I tried a few minutes of wiggling the input pointing tip tilts (TT1 and TT2) around, and then tried doing some thinking.
We note that the beam propagates (modulo a few pickoffs):
IMC -> Faraday -> TT1 -> MMT1 -> MMT2 -> TT2 -> PRM.
Since moving TT1 to the rails does make beam reflections in the BS chamber move (as seen by movement of the general illumination on the PRM face camera), I posit that the beam is getting through the Faraday. It is certainly getting at least mostly through the Faraday, although since the MC locked so easily, I assume that we didn't have too much movement after the ~2pm Alaskan earthquake & aftershocks, so we're at pretty much the same alignment as usual, in terms of beam pointing coming from the IMC.
The plan is then to see the position of the beam on MMT1, and steer using TT1 to get the beam to roughly the center. Then, see the beam propagate to MMT2 (if possible) and TT2 (if possible). From here, we should be able to see the spot on PRM. We should be able to use TT2 to tweak things up, and get the beam back to about the right place on POP, or REFL, or somewhere farther along. Hopefully at this point, we'd see some flashes in the Yarm.
Using a spare Watek camera, I was able to capture a shot of the face of MMT1. This is when the TTs were restored to their values that were saved last Monday. I checked, and this is also roughly the center of the actuation range of TT1, for both pitch and yaw.
I am not able to see the face of MMT2, or TT2. If I leave TT1, and move TT2, I am not able to see any movement of any beam or reflections seen in the PRM face camera.
Koji and I are checking the MC spot positions, but it may be time to leave this for the morning crew.
EDIT: The MC spots were actually pretty bad, and the WFS were working really hard. Koji realigned the MC suspensions, and now the MC spots are slightly better, although quite similar, to what Manasa measured last week. The restored TT values still don't give us any flashes in the arms.
[Jenne, EricQ, Manasa]
We are still not able to get the beam to go to the interferometer, which is super frustrating.
We tried using cameras and viewers to look into several ports, however all we can see is the face of MMT1, which I posted a still of last night. I have a camera looking at the back of the PRM, in hopes that we could see the beam on PRM, but no luck. The thought was that the lever arm between TT2 and PRM is so short that as long as TT2 is reasonably in the center of its range, it doesn't need to be precise. However, it seems that no matter how much I move TT1, I am not able to get a nice beam spot on PRM. Part of this is that we have to be close enough to the right alignment to hit MMT1, MMT2 and TT2.
Anyhow, we're frustrated, and I'm not sure what our next step is. I would very much prefer it if we didn't have to open any chambers, but I don't currently have any new ideas on how to see the spot on MMT2 or TT2.
The Yarm ASS is now working (as is the Xarm ASS). Both of the TT's pitch servos had a sign flip. We don't know why.
To start, we lowered the matrix elements that push on the TTs by a factor of 3, to compensate for the new factor of 3 in the slider gains: ezcastep C1:ASS-YARM_OUT_MTRX_5_5 /3 C1:ASS-YARM_OUT_MTRX_5_7 /3 C1:ASS-YARM_OUT_MTRX_6_6 /3 C1:ASS-YARM_OUT_MTRX_6_8 /3 C1:ASS-YARM_OUT_MTRX_7_5 /3 C1:ASS-YARM_OUT_MTRX_7_7 /3 C1:ASS-YARM_OUT_MTRX_8_6 /3 C1:ASS-YARM_OUT_MTRX_8_8 /3
ezcastep C1:ASS-YARM_OUT_MTRX_5_5 /3 C1:ASS-YARM_OUT_MTRX_5_7 /3 C1:ASS-YARM_OUT_MTRX_6_6 /3 C1:ASS-YARM_OUT_MTRX_6_8 /3 C1:ASS-YARM_OUT_MTRX_7_5 /3 C1:ASS-YARM_OUT_MTRX_7_7 /3 C1:ASS-YARM_OUT_MTRX_8_6 /3 C1:ASS-YARM_OUT_MTRX_8_8 /3
We turned off all 4 tip tilt ASS servos (in the Yarm ASS servo screen), and turned them on one at a time. By doing this, we discovered that the pitch servos for both TT1 and TT2 needed to have the opposite sign from what they used to have. However, the yaw servos kept the original signs. It really doesn't make sense to me why this should be, but this is the way the ASS servo works. We left both Xarm and Yarm ASSs on for several minutes, and saw that they didn't push any mirrors out of alignment.
The ASS_DOTHER_ON burt snapshot has been resaved with the new values.
Also, earlier this evening, I aligned the Yarm green beam to the cavity, although the cavity was not optimally aligned, so this needs to be re-done.
On our to-do list should be to add the tip tilt slider values to the DAQ channels list.
After the meeting, I aligned the IFO to the IR, and then I aligned the Ygreen to the Yarm. I then found the beatnotes and used ALS to hold the arms with CARM/DARM, locked the PRMI, and reduced the CARM offset until I had arm powers of about 3. Given that this was at 3pm, and people were tromping all over inside the IFO room, I feel positive about tonight.
So, IFO seems ready, carm_cm_up script was successful, and got me to arm powers of 1, and then I further reduced the offset by a bit to go a little higher.
I need to figure this out before it's worth trying any acrobatic AO path turn-on scenarios.
Also this evening, I went to the Yend and did another tweak-up of the green beam alignment.
Never mind. This is just the low pass filter that Den put in to try to deal with the moving cavity pole.
Before I realized this, just in case it was a computer quirk, Koji and I rebooted the end station front end machines. This had no effect other than to keep me searching and measuring until I figured it out. If I turn off the low pass, the phase pops back up to very close to the reference. The low pass currently comes on automatically as part of the carm_cm_up script.
REFL33, AS55, REFL55,REFL165,REFL11,POX11,POP22
There were quite a few more demodulator units labelled with PD names. Do any of them need to be included in the automated frequency response measurement system? Please let me know so that I can include them to the RF switch and check them for proper illumination, which i will do for all the above PDs next week.
In the order that makes more sense to me, it looks like you have:
REFL11, REFL33, REFL55, REFL165,
We don't really need POP22 right now, although we do want the facility to do both POP22 and POP110 for when we (eventually) put in a better PD there. Also, we want cabling for POP55, so that we can illuminate it after we re-install it. If we're working on 2f PDs, we might as well consider AS110 also, although I don't know that there was a fiber layed for it. The big one that you're missing is POY11.
I managed to recover c1sus. It required stopping all the models, and the restarting them one-by-one:
$ rtcds stop all # <-- this does the right to stop all the models with the IOP stopped last, so they will all unload properly.
$ rtcds start iop
$ rtcds start c1sus c1mcs c1rfm
I have no idea why the c1sus models got wedged, or why restarting them in this way fixed the issue.
In addition to needing obnoxiously regular mxstream restarts, this afternoon the sus machine was doing something slightly differently. Only 1 fb block per core was red (the mxstream symptom is 3 fb-related blocks are red per core), and restarting the mxstream didn't help. Anyhow, I was searching through the elog, and this entry to which I'm replying had similar symptoms. However, by the time I went back to the CDS FE screen, c1sus had regular mxstream symptoms, and an mxstream restart fixed things right up.
So, I don't know what the issue is or was, nor do I know why it is fixed, but it's fine for now, but I wanted to make a note for the future.
I'm not sure why the c1cal model didn't come up the last time c1lsc was rebooted, but I did an "rtcds start c1cal" on the lsc machine, and it's up and running now.
A few times this evening, I had been having trouble locking CARM and DARM with ALS, and holding it for very long. When it started happening again, I switched over to locking the individual arms with ALS. Yarm seems to be totally fine, but Xarm has something funny going on.
Rana and I have narrowed it down to being a problem with ETMX. We were watching ETMX's oplev and local damping error signals, and would see occasional glitch events. This happened when oplev + local damping were both on, both off, and when only local damping was on. We believe that this points to something weird with the coil driver and actuator chain.
We tried to watch for a while to see if it was a step event (something switching on and off periodically), or an impulse event (some transient oscillation in an opamp perhaps), but the problem went away again. We have come to no conclusions other than we have a problem that needs watching.
During our investigations, to more softly turn off the damping, Rana set the local damping gains, as well as the oplev gains to zero using a ramp time. We don't recall the precise numbers, and conlog doesn't have the gains recorded, so we made an educated guess. The local damping seems fine, but the oplev damping should be re-confirmed. Steve, can you please show Harry how, and have him help you measure the ETMX pitch and yaw oplev loops, and set the gains so that they match up to the references, and then post the measured bode plots when you're done?
c1auxex has forgotten who it is. Slow sliders for the QPD head were not responding, so I did a soft reboot from telnet. The machine didn't come back, so I plugged the RJ45-DB9 cable into the machine and looked at it through a minicom session. When I key the crate, it gives me an error that it can't load a file, with the error code 0x320001. Looking that up on a List of VxWorks error codes, I see that it is: S_hostLib_UNKNOWN_HOST (3276801 or 0x320001)
I'm not sure how this happened. I unplugged and replugged in the ethernet cable on the computer, but that didn't help. Rana is going in to wiggle the other end of the ethernet cable, in case that's the problem. EDIT: Replacing the ethernet cable did not help.
Former elogs that are useful: 10025, 10015
EDIT: The actual error message is:
boot device : ei
processor number : 0
host name : chiara
file name : /cvs/cds/vw/mv162-262-16M/vxWorks
inet on ethernet (e) : 192.168.113.59:ffffff00
host inet (h) : 192.168.113.104
user (u) : controls
flags (f) : 0x0
target name (tn) : c1auxex
startup script (s) : /cvs/cds/caltech/target/c1auxex/startup.cmd
Attaching network interface ei0... done.
Attaching network interface lo0... done.
Error loading file: errno = 0x320001.
Can't load boot file!!
We have decided to keep better track (using new-fangled digital "computers") of our modifications to electronics boards.
The idea will be to create a new DCC document for every electronics board (when we pull a board and modify it, it should receive this treatment) that we have, and that document will become a history of the board's life. Version 1 will be a copy of the original drawing. Version 2 should be a modified version of that drawing with the current situation. All future versions should be modified from the most recent version, to reflect any changes. Notes for each updated version should include an elog reference to the work, so that we know why we did things, and have a place to find photos of the actual modifications. Elogs should also include a link to the DCC version. DCC titles should include the phrase "40m Revisions" for ease of searching.
Patient Zero for this new system will be the PMC servo card. The DCC number is D1400221. As of this moment, this just has the V1 original drawing with no modifications.
This has been included in the 40m's DCC document tree that Jamie started back in November 2012.
I have put in a new nominal value for the FSS fast gain: 21.5 dB.
There is an oscillation peak in the MC error point spectra around 41.5 kHz if the FSS gain is set too high. I used the 4395 to have a look at the MC error point, and saw that if I set the FSS fast gain any lower than about 18 dB, the peak wasn't getting any smaller than -41 dBm. If I set the fast gain any higher than about 26 dB the peak wouldn't get any larger than about -34 dBm.
However, if I set the gain to 19.5dB, the PC RMS drive is consistently above 2 V, which isn't so good. If I crank the gain up to 27 dB or more, the PC RMS will stay below 0.9 V, which is great.
As a compromise, I have decided on 21.5 dB as the new FSS fast gain. This puts the oscillation peak at about -39.5 dBm, and the PC RMS around 1.6 V.
I changed the nominal gain by ezcawrite C1:PSL-STAT_FSS_NOM_F_GAIN 21.5. This sets the nominal value so that the FSS screen's fast slider doesn't turn red at the new value. And, since the MC autolocker reads this epics channel and puts that into the gain during the mcup script, the MC autolocker now uses this new gain. For reference, it used to be set to 23.5 dB.
ezcawrite C1:PSL-STAT_FSS_NOM_F_GAIN 21.5
I have put beam dumps in front of both of the end transmission QPDs so that I could measure the dark noise. They are still there.
I checked that the Yend QPD sliders and switches were doing things as I expected. I couldn't do the Xend since c1auxex is still lost (elog 10165). I'll post plots and actual information on this checkout, as well as my calculation of what this dark noise means in terms of meters for CARM when we're using 1/sqrt(trans) signals tomorrow morning.
Measurement of Yend transmission QPD dark noise
Since EricQ had already checked out the whitening filters (see elog 9637 and elog 9642), I didn't check on them. I just left them (the analog whitening, and the digital antiwhitening filters) on.
First, I checked the noise vs. transimpedance gain. There are a few too many settings to put them all on one plot, so I have them sorted by the original transimpedance: 0.5 kOhms vs 5 kOhms. It's a little tricky to see, but all of the spectra that begin with the 5k transimpedance have a little extra noise around 10 Hz, although I don't know why. In the legend I have made note of what the settings were. x1 x1 is my representation of the "inactive" setting.
I then looked at the noise with different whitening gain slider settings. All but one of the traces are the 20 kOhm setting.
These .xml files are in /users/jenne/Arms/TransQPDnoise_July2014/
Calculation of inverse sqrt transmission sensitivity
I used Optickle to give me the power transmitted through the ETMs. I first find the transmission in the FPMI case. I use that to normalize the full PRFPMI transmission, so that the output units are the same as our C1:LSC-TR[x,y]_OUT units.
I take the square root of the transmitted power (sum of transmissions from each arm) at each CARM offset point, add 1e-3 as we do in the front end model to prevent divide-by-zero problems, and then take the inverse.
I find the slope by taking the difference in power between adjacent points, divided by the CARM offset difference between those points.
In this plot, I have taken the absolute value of the sensitivity, just for kicks. I also display an arbitrarily scaled version of the log of the transmitted power, so that we can see that the highest sensitivity is at half the maximum power.
Calculate the QPD dark noise in terms of meters
Finally, I put it all together, and find the dark noise of the QPD in terms of meters. Since the spectra were measured in units where the single-arm transmission is unity, the already match the units that I used to calculate the sqrtInv sensitivity.
I take the spectra of the QPD dark noise for the 20 kOhm case, and multiply it by the sensitivity calibration number at several different CARM offsets. As we expect, the noise is the best at half-max transmission, where the sensitivity is maximal.
I'm starting to lock for the night, and I noticed that PRM is very, very pitched. Why? The PRM pitch slider is 5 full integer units higher than the backup (and the backup value is about where I like it, around -0.2).
I am not aware of any scripts that touch the PRM slider values. The PRM ASS (which I haven't used in ages) offloads the biases to the SUS screen fast channels, so even if someone turned that on and then saved the values, it wouldn't leave the PRM so very, very misaligned.
I have restored it, and relocked the PRMI, so all is well, but it's very weird to have found it so misaligned.
I took some data tonight for a quick look at what combinations of DC signals might be good to use for DARM, as an alternative to ALS before we're ready for RF.
I had the arms locked with ALS, PRMI with REFL33, and tried to move the CARM offset between plus and minus 1. The PRMI wasn't holding lock closer than about -0.3 or +0.6, so that is also a problem. Also, I realized just now that I have left the beam dumps in front of the transmission QPDs, so I had prevented any switching of the trans PD source. This means that all of my data for C1:LSC-TR[x,y]_OUT_DQ is taken with the Thorlabs PDs, which is fine, although they saturate around arm powers of 4 ever since my analog gain increase on the whitening board. Anyhow, the IFO didn't hold lock for much beyond then anyway, so I didn't miss out on much. I need to remember to remove the dumps though!!
Self: Good stuff should be between 12:50am - 1:09am. One set of data was ./getdata -s 1089445700 -d 30 -c C1:LSC-TRX_OUT_DQ C1:LSC-TRY_OUT_DQ C1:LSC-CARM_IN1_DQ C1:LSC-PRCL_IN1_DQ
./getdata -s 1089445700 -d 30 -c C1:LSC-TRX_OUT_DQ C1:LSC-TRY_OUT_DQ C1:LSC-CARM_IN1_DQ C1:LSC-PRCL_IN1_DQ
I removed the dumps in front of the trans QPDs. The Yend QPD needed re-normalization, so I did that.
I realized while I was looking at last night's data that I had been doing CARM sweeps, when really I wanted to be doing DARM sweeps. I took a few sets of data of DARM sweeps while locked on ALSdiff. However, Rana pointed out that comparing ALSdiff to TRX-TRY isn't exactly a fair comparison while I'm locked on ALSdiff, since it's an in-loop signal, so it looks artificially quiet.
Anyhow, I may consider transitioning DARM over to AS55 temporarily so that I can look at both as out-of-loop sensors.
Also, so that I can try locking DARM on DC transmission, I have added 2 more columns to the LSC input matrix (now we're at 32!), for TRX and TRY. We already had sqrt inverse versions of these signals, but the plain TRX and TRY were only available as normalization signals before. Since Koji put in the facility to sqrt or not the normalization signals, I can now try:
Option 1: ( TRX - TRY ) / (TRX + TRY)
Option 2: ( TRX - TRY ) / sqrt( TRX + TRY )
DARM does not yet have the facility to normalize one signal (DC transmission) and not another (ALS diff), so I may need to include that soon. For tonight, I'm going to try just changing matrix elements with ezcastep.
Since I changed the c1lsc.mdl model, I compiled it, restarted the model, and checked the model in. I have also added these 2 columns to the AUX_ERR sub-screen for the LSC input matrix. I have not changed the LSC overview screen.
We had a look at the RIN of the transmission signals TRX and TRY, when the arms were individually locked on IR. If the intensity noise is very bad, then the transmission signals aren't really a good option to use for locking. So, if the RIN is bad, we need to work on our intensity stabilization.
We need to understand what the situation is with the AOM, and why it isn't working as expected, so that we can reinstall it. We also need to decide if we're going to use the SR560 setup, or if the Chas ISS is sufficiently characterized for us to use.
The RIN is certainly bad. Also, I don't know why the Xarm's RIN is worse between 10 Hz and a few hundred Hz than the Yarm.
I looked at what the RIN contribution of the sqrtInv sensor is by locking the arms individually on IR using POX and POY. I then took spectra of the sqrtInv channels. For the Xarm, I had forced the triggering so that the QPD was being used as the transmission PD, while the Yarm was using the regular Thorlabs PD. I also had the green lasers locked to the arms, and took beatnote spectra to see what the sensing noise of the beatnotes is, all at the same time.
For the sqrtInv channels, I used the Optickle calibration from elog 10187. For today's plot, I am using the calibration at about 1nm, since that is about where we are when we transition to the sqrtInv Thorlabs signal usually.
For the ALS channel, I was using the _FINE_PHASE_OUT signal, which is in units of degrees of phase for a single green wavelength. So, since k * x = phi, I want the phase data to be converted to radians (2*pi/360), and use k = 2*pi / lambda_green. So, doing some algebra, this gives me x = phi_degrees * lambda / 360 for my calibration.
What I see in the plot is that the ALS sensing noise is pretty bad compared to the sqrtInv channels, so maybe we don't have to work so hard on the ISS this next week. Also, the Thorlabs PD is much better than the QPDs, which maybe isn't so surprising since we have them set so that they have good SNR at higher power.
Anyhow, here's the plot:
Also, here is the Thorlabs PD only, with single arm locked on RF, with the noise calibrated to different CARM offsets:
As Koji pointed out, I messed up the calibration. However, fixing it doesn't change things that much.
From this calibration by Yuta, the Xarm ALS calibration is 54 deg / MHz, or 19.17 kHz / deg. So, I multiply my data which is in these degree units by 19.17e3 to get Hz. Then I use delta_f / f = delta_L / L to convert to meters. f = c / lambda_green, and L = 37.5 meters.
This only changes the calibration by about 10-15%. It still looks like the ALS noise is well above the RIN level of the sqrtInv signal.
Q is working on fixing the "save offsets" script for the ASS, because that has lost me my alignment two more times in the last few hours. But, right now I have both arms locked with transmitted powers of about 0.9! To get this, I ran the ASS scripts, and hand-tweaked the bias sliders of some of the optics to relieve the ASS outputs. Then I turned the ASS gain to zero, and by-hand turned off the oscillators. So, the ASS outputs are just frozen.
I haven't seen IMTX suspension kicks, I think since Q did the front end reboot earlier. There has been ITMY activity, however. I think I'm going to be bold, and try locking ALS.
After aligning the arms to IR, I aligned the Y green beam to the arm. Also, the X green beatnote was very small, so I aligned the PSL green for X.
The ALS system is iffy tonight.
After putting the cable back to the RF spectrum analyzer (it had been taken to test the frequency counter setup, and not put back), I had a good Yarm beatnote, but again this evening the Xarm beatnote is small. I touched up the PSL table alignment (very, very little needed, but it did double my peak height). I *think* that this is happening because we haven't settled into a good IFO alignment place, so the arm pointing keeps changing very slightly, which means that the PSL ALS alignment needs touching. Anyhow, even after alignment the Xarm beatnote is only -36 dBm at 81 MHz. It should be at least -25 dBm or so, although I haven't seen it any larger than about -35 dBm since the IFO beam was lost last Friday.
I am not able to hold ALS lock long enough to scan the arms and find the IR resonances. The only optics that I am actuating on this evening are the 2 ETMs. When I lose lock and look at the watchdogs, the ETMs are the only optics that have largeish numbers, which comes from the ALS lockloss. So, I don't think I am suffering from the ITM suspension kicks tonight. Rather, I think that it's that the ALS system isn't tuned up nicely.
I think that it is past time we tuned up and checked out the ALS PDH setup. Q: Can you please measure the loop TFs for both of the ALS PDH boxes tomorrow? At the very least we want to know what we're working with.
Evan: What is the status with the ISS?
I am going to try tomorrow to look at the suspensions, and see if I can track anything down. I feel like I see the kicks more often when the arms are locked, i.e. we are sending an LSC signal to them. The LSC POS signal is a factor of a few hundred larger than the damping SUSPOS signal is. Are we saturating something somewhere? Why is this a new thing? We certainly do see kicks when the LSC is not engaged, so this may not be the right path, but it is something concrete to look at.
The MC has been unstable and unhappy for the last several hours. When I looked, I saw that the FSS_FAST monitor has been hovering around 1 V, when it is supposed to be closer to 5ish.
I changed the C1:PSL-FSS_INOFFSET from -0.08 to -0.8537, and will see if the MC sticks around for longer this time around.