Related elog thread: 16286

I didn't really achieve anything but I'm listing what I've tried.

• I know now that the timesyncd isn't working because systemd-timesyncd is known to have issues when running on a read-only file system. In particular, the service does not have privileges to change the clock or drift settings at /run/systemd/clock or /etc/adjtime.
• The workarounds to these problems are poorly rated/reviews in stack exchange and require me to change the /etc/systmd/timesyncd.conf file but I'm unable to edit this file.
• I know that Paco was able to change these files earlier as the files are now changed and configured to follow a debian ntp pool server which won't work as the FEs do not have internet access. So the conf file needs to be restored to using ntpserver as the ntp server.
• From system messages, the ntpserver is recognized by the service as shown in the second part of 16285. I really think the issue is in file permissions. the file /etc/adjtime has never been updated since 2017.
• I got help from Paco on how to edit files for FE machines. The FE machines directories are exported from fb1:/diskless/root.jessie/
• I restored the /etc/systmd/timesyncd.conf file to how it as before with just servers=ntpserver line. Restarted timesyncd service on all FEs,I tried a few su the synchronization did not happen.
• I tried a few suggestions from stackexchange but none of them worked. The only rated solution creates a tmpfs directory outside of read-only filesystem and uses that to run timesyncd. So, in my opinion, timesyncd  would never work in our diskless read-only file system FE machines.
• One issue in an archlinux discussion ended by the questioner resorting to use opennptd from openBSD distribution. The user claimed that opennptd is simple enough that it can run ntp synchornization on a read-only file system.
• Somehwat painfully, I 'kind of' installed the openntpd tool in the fb1:/diskless/root.jessie directory following directions from here. I had to manually add user group and group for the FEs (which I might not have done correctly). I was not able to get the openntpd daemon to start properly after soe tries.
• I restored everything back to how it was and restarted timesyncd in c1sus even though it would not do anything really.

Jamie told me to use chroot to log in into the chroot jail of debian os that are exported for the FEs and install ntp there. I took following steps at the end of which, all FEs have NTP synchronized now.

• I logged into fb1 through nodus.
• chroot /diskless/root.jessie /bin/bash took me to the bash terminal for debian os that is exported to all FEs.
• Here, I ran sudo apt-get install ntp which ran without any errors.
• I then edited the file in /etc/ntp.conf , i removed the default servers and added following lines for servers (fb1 and nodus ip addresses):
  server 192.113.168.201
  server 192.113.168.201
• I logged into each FE machine and ran following commands:
  sudo systemctl stop systemd-timesyncd.service; sudo systemctl status systemd-timesyncd.service;
  timedatectl; sleep 2;sudo systemctl daemon-reload;  sudo systemctl start ntp; sleep 2; sudo systemctl status ntp; timedatectl
  sudo hwclock -s
  • The first line ensures that systemd-timesyncd.service is not running anymore. I did not uninstall timesyncd and left its configuration file as it is.
  • The second line first shows the times of local and RTC clocks. Then reloads the daemon services to get ntp registered. Then starts ntp.service and shows it's status. Finally, the timedatectl command shows the synchronized clocks and that NTP synchronization has occured.
  • The last line sets the local clock same as RTC clock. Even though this wasn't required as I saw that the clocks were already same to seconds, I just wanted a point where all the local clocks are synchronized to the ntp server.
• Hopefully, this would resolve our issue of restarting the models anytime some glitch happens or when we need ot update something in one of them.

Edit Tue Aug 24 10:19:11 2021:

I also disabled timesyncd on all FEs using sudo systemctl disable systemd-timesyncd.service

I've added this wiki page for summarizing the NTP synchronization knowledge.

tl;dr: NTP servers and clients were never synchronized, are not synchronizing even with ntp... nodus is synchronized but uses chronyd; should we use chronyd everywhere?

Spent some time investigating the ntp synchronization. In the morning, after Anchal set up all the ntp servers / FE clients I tried restarting the rts IOPs with no success. Later, with Tega we tried the usual manual matching of the date between c1iscex and fb1 machines but we iterated over different n-second offsets from -10 to +10, also without success.

This afternoon, I tried debugging the FE and fb1 timing differences. For this I inspected the ntp configuration file under /etc/ntp.conf in both the fb1 and /diskless/root.jessie/etc/ntp.conf (for the FE machines) and tried different combinations with and without nodus, with and without restrict lines, all while looking at the output of sudo journalctl -f on c1iscey. Everytime I changed the ntp config file, I restarted the service using sudo systemctl restart ntp.service . Looking through some online forums, people suggested basic pinging to see if the ntp servers were up (and broadcasting their times over the local network) but this failed to run (read-only filesystem) so I went into fb1, and ran sudo chroot /diskless/root.jessie/ /bin/bash to allow me to change file permissions. The test was first done with /bin/ping which couldn't even open a socket (root access needed) by running chmod 4755 /bin/ping then ssh-ing into c1iscey and pinging the fb1 machine successfully. After this, I ran chmod 4755 /usr/sbin/ntpd so that the ntp daemon would have no problem in reaching the server in case this was blocking the synchronization. I exited the chroot shell and the ntp daemon in c1iscey; but the ntpstat still showed unsynchronised status. I also learned that when running an ntp query with ntpq -p if a client has succeeded in synchronizing its time to the server time, an asterisk should be appended at the end. This was not the case in any FE machine... and looking at fb1, this was also not true. Although the fb1 peers are correctly listed as nodus, the caltech ntp server, and a broadcast (.BCST.) server from local time (meant to serve the FE machines), none appears to have synchronized... Going one level further, in nodus I checked the time synchronization servers by running chronyc sources the output shows

controls@nodus|~> chronyc sources
210 Number of sources = 4
MS Name/IP address         Stratum Poll Reach LastRx Last sample
===============================================================================
^* testntp1.superonline.net      1  10   377   280  +1511us[+1403us] +/-   92ms
^+ 38.229.59.9                   2  10   377   206  +8219us[+8219us] +/-  117ms
^+ tms04.deltatelesystems.ru     2  10   377   23m    -17ms[  -17ms] +/-  183ms
^+ ntp.gnc.am                    3  10   377   914  -8294us[-8401us] +/-  168ms

I then ran chronyc clients to find if fb1 was listed (as I would have expected) but the output shows this --

Hostname                   Client    Peer CmdAuth CmdNorm  CmdBad  LstN  LstC
=========================  ======  ======  ======  ======  ======  ====  ====
501 Not authorised

So clearly chronyd succeeded in synchronizing nodus' time to whatever server it was pointed at but downstream from there, neither the fb1 or any FE machines seem to be synchronizing properly. It may be as simple as figuring out the correct ntp configuration file, or switching to chronyd for all machines (for the sake of homogeneity?)

Dan Kozak pointed out that the new frame files of the 40m has not been written in 2021 GPS time but 2020 GPS time.

Current GPS time is 1313890914 (or something like that), but the new files are written as C-R-1282268576-16.gwf

I don't know how this can happen but this may explain why we can't have the agreement between the FB gps time and the RTS gps time.

(dataviewer seems dependent on the FB GPS time and it indicates 2020 date. DTT/diaggui does not.)

This is the way to check the gpstime on fb1. It's apparently a year off.

controls@fb1:~ 0$ cat /proc/gps
1282269402.89

I attempted to install chrony and run it on one of the FE machines. It didn't work and in doing so, I lost the working NTP client service on the FE computers as well. Following are some details:

• I added the following two mirrors in the apt source list of root.jessie at /etc/apt/sources.list
  deb http://ftp.us.debian.org/debian/ jessie main contrib non-free
  deb-src http://ftp.us.debian.org/debian/ jessie main contrib non-free
• Then I installed chrony in the root.jessie using
  sudo apt-get install chrony
  • I was getting an error E: Can not write log (Is /dev/pts mounted?) - posix_openpt (2: No such file or directory) . To fix this, I had to run:
    sudo mount -t devpts none "$rootpath/dev/pts" -o ptmxmode=0666,newinstance
    sudo ln -fs "pts/ptmx" "$rootpath/dev/ptmx"
  • Then, I had another error to resolve.
    Failed to read /proc/cmdline. Ignoring: No such file or directory
    start-stop-daemon: nothing in /proc - not mounted?
    To fix this, I had to exit to fb1 and run:
    sudo mount --bind /proc /diskless/root.jessie/proc
  • With these steps, chrony was finally installed, but I immediately saw an error message saying:
    Starting /usr/sbin/chronyd...
    Could not open NTP sockets
• I figured this must be due to ntp running in the FE machines.  I logged into c1iscex and stopped and disabled the ntp service:
  sudo systemctl stop ntp
  sudo systemctl disable ntp
  • I saw some error messages from the above coomand as FEs are read only file systems:
    Synchronizing state for ntp.service with sysvinit using update-rc.d...
    Executing /usr/sbin/update-rc.d ntp defaults
    insserv: fopen(.depend.stop): Read-only file system
    Executing /usr/sbin/update-rc.d ntp disable
    update-rc.d: error: Read-only file system
  • So I went back to chroot in fb1 and ran the two command sabove that failed:
    /usr/sbin/update-rc.d ntp defaults
    /usr/sbin/update-rc.d ntp disable
  • The last line gave the output:
    insserv: warning: current start runlevel(s) (empty) of script `ntp' overrides LSB defaults (2 3 4 5).
    insserv: warning: current stop runlevel(s) (2 3 4 5) of script `ntp' overrides LSB defaults (empty).
  • I igored this and moved forward.
• I copied the chronyd.service from nodus to the chroot in fb1 and configured it to use nodus as the server. The I started the chronyd.service

  sudo systemctl status chronyd.service
  but got the saem issue of NTP sockets.

  â—Â� chronyd.service - NTP client/server
     Loaded: loaded (/usr/lib/systemd/system/chronyd.service; disabled)
     Active: failed (Result: exit-code) since Tue 2021-08-24 21:52:30 PDT; 5s ago
    Process: 790 ExecStart=/usr/sbin/chronyd $OPTIONS (code=exited, status=1/FAILURE)

  Aug 24 21:52:29 c1iscex systemd[1]: Starting NTP client/server...
  Aug 24 21:52:30 c1iscex chronyd[790]: Could not open NTP sockets
  Aug 24 21:52:30 c1iscex systemd[1]: chronyd.service: control process exited, code=exited status=1
  Aug 24 21:52:30 c1iscex systemd[1]: Failed to start NTP client/server.
  Aug 24 21:52:30 c1iscex systemd[1]: Unit chronyd.service entered failed state.

• I tried a few things to resolve this, but couldn't get it to work. So I gave up on using chrony and decided to go back to ntp service atleast.

• I stopped, disabled and checked status of chrony:
  sudo systemctl stop chronyd
  sudo systemctl disable chronyd
  sudo systemctl status chronyd
  This gave the output:

  â—Â� chronyd.service - NTP client/server
     Loaded: loaded (/usr/lib/systemd/system/chronyd.service; disabled)
     Active: failed (Result: exit-code) since Tue 2021-08-24 22:09:07 PDT; 25s ago

  Aug 24 22:09:07 c1iscex systemd[1]: Starting NTP client/server...
  Aug 24 22:09:07 c1iscex chronyd[2490]: Could not open NTP sockets
  Aug 24 22:09:07 c1iscex systemd[1]: chronyd.service: control process exited, code=exited status=1
  Aug 24 22:09:07 c1iscex systemd[1]: Failed to start NTP client/server.
  Aug 24 22:09:07 c1iscex systemd[1]: Unit chronyd.service entered failed state.
  Aug 24 22:09:15 c1iscex systemd[1]: Stopped NTP client/server.

• I went back to fb1 chroot and removed chrony package and deleted the configuration files and systemd service files:
  sudo apt-get remove chrony

• But when I started ntp daemon service back in c1iscex, it gave error:
  sudo systemctl restart ntp
  Job for ntp.service failed. See 'systemctl status ntp.service' and 'journalctl -xn' for details.

• Status shows:

  sudo systemctl status ntp
  â—Â� ntp.service - LSB: Start NTP daemon
     Loaded: loaded (/etc/init.d/ntp)
     Active: failed (Result: exit-code) since Tue 2021-08-24 22:09:56 PDT; 9s ago
    Process: 2597 ExecStart=/etc/init.d/ntp start (code=exited, status=5)

  Aug 24 22:09:55 c1iscex systemd[1]: Starting LSB: Start NTP daemon...
  Aug 24 22:09:56 c1iscex systemd[1]: ntp.service: control process exited, code=exited status=5
  Aug 24 22:09:56 c1iscex systemd[1]: Failed to start LSB: Start NTP daemon.
  Aug 24 22:09:56 c1iscex systemd[1]: Unit ntp.service entered failed state.

• I tried to enable back the ntp service by sudo systemctl enable ntp. I got similar error messages of read only filesystem as earlier.
  Synchronizing state for ntp.service with sysvinit using update-rc.d...
  Executing /usr/sbin/update-rc.d ntp defaults
  insserv: warning: current start runlevel(s) (empty) of script `ntp' overrides LSB defaults (2 3 4 5).
  insserv: warning: current stop runlevel(s) (2 3 4 5) of script `ntp' overrides LSB defaults (empty).
  insserv: fopen(.depend.stop): Read-only file system
  Executing /usr/sbin/update-rc.d ntp enable
  update-rc.d: error: Read-only file system

  • I went back to chroot in fb1 and ran:
    /usr/sbin/update-rc.d ntp defaults
    insserv: warning: current start runlevel(s) (empty) of script `ntp' overrides LSB defaults (2 3 4 5).
    insserv: warning: current stop runlevel(s) (2 3 4 5) of script `ntp' overrides LSB defaults (empty).
    and
    /usr/sbin/update-rc.d ntp enable

• I came back to c1iscex and tried restarting the ntp service but got same error messages as above with exit code 5.

• I checked c1sus, the ntp was running there. I tested the configuration by restarting the ntp service, and then it failed with same error message. So the remaining three FEs, c1lsc, c1ioo and c1iscey have running ntp service, but they won't be able to restart.

• As a last try, I rebooted c1iscex to see if ntp comes back online nicely, but it doesn't.

Bottom line, I went to try chrony in the FEs, and I ended up breaking the ntp client services on the computers as well. We have no NTP synchronization in any of the FEs.

Even though Paco and I are learning about the ntp and cds stuff, I think it's time we get help from someone with real experience. The lab is not in a good state for far too long.

8 of the 2"->3" adapter rings (D2100377) arrived from RDL yesterday. I have not tested the threads but dimensional inspection on SN008 cleared. Parts look very good. The rest of the parts should be shipping out in the next week.

After confirming that, indeed, leaving the RTN connection floating can cause reliability issues we decided to make these connections in the c1auxex analog input units.

According to Johannes' wiring scheme (excluding the anti-image and OPLEV since they are decommissioned), Acromag unit 1221b accepts analog inputs from two modules. All of these channels are single-ended according to their schematics.

One option is to use the Acromag ground and connect it to the RTNs of both 1221b and 1221c. Another is to connect the minus wire of one module, which is tied to the module's ground, to the RTN. We shouldn't tie the grounds of the different modules together by connecting them to the same RTN point.

We should take some OSEM spectra of the X end arm before and after this work to confirm we didn't produce more noise by doing so. Right now, it is impossible due to issues caused by the recent power surge.

[paco, tega, koji]

After invaluable assistance from Jamie in fixing this yearly offset in the gps time reported by cat /proc/gps, we managed to restart the real time system correctly (while still manually synchronizing the front end machine times). After this, we recovered the mode cleaner and were able to lock the arms with not much fuss.

Nevertheless, tega and I noticed some weird noise in the C1:LSC-TRX_OUT which was not present in the YARM transmission, and that is present even in the absence of light (we unlocked the arms and just saw it on the ndscope as shown in Attachment #1). It seems to affect the XARM and in general the lock acquisition...

We took some quick spectrum with diaggui (Attachment #2) but it doesn't look normal; there seems to be broadband excess noise with a remarkable 1 kHz component. We will probably look into it in more detail.

I have no idea what happened to the GPS timing on fb1, but it seems like the issue was coincident with the power glitch on Monday.

As was noted by Koji above, the GPS time kernel interface was off by a year, which was causing the frame builder to write out files with the wrong names.  fb1 was using DAQD components from the advligorts 3.3 release, which used the old "symmetricom" kernel module for the GPS time.  This old module was also known to have issues with time offsets.  This issue is remniscent of previous timing issues with the DAQ on fb1.

I noted that a newer version of the advligorts, version 3.4, was available on debian jessie, the system running on fb1.  advligorts 3.4 includes a newer version of the GPS time module, renamed gpstime.  I checked with Jonathan Hanks that the interfaces did not change between 3.3 and 3.4, and 3.4 was mostly a bug fix and packaging release, so I decided to upgrade the DAQ to get the new components.  I therefore did the following

• updated the archive info in /etc/apt/sources.list.d/cdssoft.list, and added the "jessie-restricted" archive which includes the mx packages: https://git.ligo.org/cds-packaging/docs/-/wikis/home

• removed the symmetricom module from the kernel
  
  sudo rmmod symmetricom

• upgraded the advligorts-daqd components (NOTE I did not upgrade the rest of the system, although there are outstanding security upgrades needed):
  
  sudo apt install advligorts-daqd advligorts-daqd-dc-mx

• loaded the new gpstime module and checked that the GPS time was correct:
  
  sudo modprobe gpstime

• restarted all the daqd processes
  
  sudo systemctl restart daqd_*

Everything came up fine at that point, and I checked that the correct frames were being written out.

[paco, ]

We went over the X end to check what was going on with the TRX signal. We spotted the ground terminal coming from the QPD is loosely touching the handle of one of the computers on the rack. When we detached it completely from the rack the noise was gone (attachment 1).

We taped this terminal so it doesn't touch anything accidently. We don't know if this is the best solution since it is probably needs a stable voltage reference. In the Y end those ground terminals are connected to the same point on the rack. The other ground terminals in the X end are just cut.

We also took the PSD of these channels (attachment 2). The noise seem to be gone but TRX is still a bit noisier than TRY. Maybe we should setup a proper ground for the X arm QPD?

We saw that the X end station ALS laser was off. We turned it on and also the crystal oven and reenabled the temperature controller. Green light immidiately appeared. We are now working to restore the ALS lock. After running XARM ASS we were unable to lock the green laser so we went to the XEND and moved the piezo X ALS alignment mirrors until we maximized the transmission in the right mode. We then locked the ALS beams on both arms successfully. It very well could be that the PZT offsets were reset by the power glitch. The XARM ALS still needs some tweaking, its level is ~ 25% of what it was before the power glitch.

I've been looking at why the front end NTP time synchronization did not seem to be working.  I think it might not have been working because the NTP server the front ends were point to, fb1, was not actually responding to synchronization requests.

I cleaned up some things on fb1 and the front ends, which I think unstuck things.

On fb1:

• stopped/disabled the default client (systemd-timesyncd), and properly installed the full NTP server (ntp)
• the ntp server package for debian jessie is old-style sysVinit, not systemd.  In order to make it more integrated I copied the auto-generated service file to /etc/systemd/system/ntp.service, and added and "[install]" section that specifies that it should be available during the default "multi-user.target".
• "enabled" the new service to auto-start at boot ("sudo systemctl enable ntp.service") 
• made sure ntp was configured to serve the front end network ('broadcast 192.168.123.255') and then restarted the server ("sudo systemctl restart ntp.service")

For the front ends:

• on fb1 I chroot'd into the front-end diskless root (/diskless/root) and manually specifed that systemd-timesyncd should start on boot by creating a symlink to the timesyncd service in the multi-user.target directory:

$ sudo chroot /diskless/root
$ cd /etc/systemd/system/multi-user.target.wants
$ ln -s /lib/systemd/system/systemd-timesyncd.service

• on the front end itself (c1iscex as a test) I did a "systemctl daemon-reload" to force it to reload the systemd config, and then restarted the client ("systemctl restart systemd-timesyncd")
• checked the NTP synchronization with timedatectl:

controls@c1iscex:~ 0$ timedatectl 
      Local time: Thu 2021-08-26 11:35:10 PDT
  Universal time: Thu 2021-08-26 18:35:10 UTC
        RTC time: Thu 2021-08-26 18:35:10
       Time zone: America/Los_Angeles (PDT, -0700)
     NTP enabled: yes
NTP synchronized: yes
 RTC in local TZ: no
      DST active: yes
 Last DST change: DST began at
                  Sun 2021-03-14 01:59:59 PST
                  Sun 2021-03-14 03:00:00 PDT
 Next DST change: DST ends (the clock jumps one hour backwards) at
                  Sun 2021-11-07 01:59:59 PDT
                  Sun 2021-11-07 01:00:00 PST
controls@c1iscex:~ 0$ 

Note that it is now reporting "NTP enabled: yes" (the service is enabled to start at boot) and "NTP synchronized: yes" (synchronization is happening), neither of which it was reporting previously.  I also note that the systemd-timesyncd client service is now loaded and enabled, is no longer reporting that it is in an "Idle" state and is in fact reporting that it synchronized to the proper server, and it is logging updates:

controls@c1iscex:~ 0$ sudo systemctl status systemd-timesyncd
â—� systemd-timesyncd.service - Network Time Synchronization
   Loaded: loaded (/lib/systemd/system/systemd-timesyncd.service; enabled)
   Active: active (running) since Thu 2021-08-26 10:20:11 PDT; 1h 22min ago
     Docs: man:systemd-timesyncd.service(8)
 Main PID: 2918 (systemd-timesyn)
   Status: "Using Time Server 192.168.113.201:123 (ntpserver)."
   CGroup: /system.slice/systemd-timesyncd.service
           â””─2918 /lib/systemd/systemd-timesyncd

Aug 26 10:20:11 c1iscex systemd[1]: Started Network Time Synchronization.
Aug 26 10:20:11 c1iscex systemd-timesyncd[2918]: Using NTP server 192.168.113.201:123 (ntpserver).
Aug 26 10:20:11 c1iscex systemd-timesyncd[2918]: interval/delta/delay/jitter/drift 64s/+0.000s/0.000s/0.000s/+26ppm
Aug 26 10:21:15 c1iscex systemd-timesyncd[2918]: interval/delta/delay/jitter/drift 128s/-0.000s/0.000s/0.000s/+25ppm
Aug 26 10:23:23 c1iscex systemd-timesyncd[2918]: interval/delta/delay/jitter/drift 256s/+0.001s/0.000s/0.000s/+26ppm
Aug 26 10:27:40 c1iscex systemd-timesyncd[2918]: interval/delta/delay/jitter/drift 512s/+0.003s/0.000s/0.001s/+29ppm
Aug 26 10:36:12 c1iscex systemd-timesyncd[2918]: interval/delta/delay/jitter/drift 1024s/+0.008s/0.000s/0.003s/+33ppm
Aug 26 10:53:16 c1iscex systemd-timesyncd[2918]: interval/delta/delay/jitter/drift 2048s/-0.026s/0.000s/0.010s/+27ppm
Aug 26 11:27:24 c1iscex systemd-timesyncd[2918]: interval/delta/delay/jitter/drift 2048s/+0.009s/0.000s/0.011s/+29ppm
controls@c1iscex:~ 0$ 

So I think this means everything is working.

I then went ahead and reloaded and restarted the timesyncd services on the rest of the front ends.

We still need to confirm that everything comes up properly the next time we have an opportunity to reboot fb1 and the front ends (or the opportunity is forced upon us).

There was speculation that the NTP clients on the front ends (systemd-timesyncd) would not work on a read-only filesystem, but this doesn't seem to be true.  You can't trust everything you read on the internet.

Used diaggui to get OLTF in preparation for optimal system identification / calibration. The excitation was injected at the control point of the XARM loop C1:LSC-XARM_EXC. Attachment 1 shows the TF (red scatter) taken from 35 Hz to 2.3 kHz with 201 points. The swept sine excitation had an envelope amplitude of 50 counts at 35 Hz, 0.2 counts at 100 Hz, and 0.2 at 200 Hz. In purple continous line, the model for the OLTF using all the digital control filters as well as a simple 1 degree of freedom plant (single pole at 0.99 Hz) is overlaid. Note the disagreement of the OLTF "model" at higher frequencies which we may be able to improve upon using vector fitting.

Attachment 2 shows the coherence (part of this initial measurement was to identify an appropriately large frequency range where the coherence is good before we script it).

this model doesn't seem to include the analog AA, analog AI, digital AA, digital AI, or data transfer delays in the system. I think if you include those you will get more accuracy at high frequencies. Probably Anchal has those included in his DARM loop model?

The right N2 tank had a bad/loose valve and did not fully open. This morning the left tank was just about empty and the right tank showed 2000+ psi on the gauge. Once the changeover happened the copper line emptied but the valve to the N2 tank was not fully opened. I noticed the gauges were both reading zero at ~1pm just before the meeting. I swapped the left tank, but not in time. The vacuum interlocks tripped at 1:04 pm today when the N2 pressure to the vacuum valves fell below 65psi. After the meeting, Chub tightened the valve, fully opened it and refilled the lines. I will monitor the tank pressures today and make sure all is ok.

There used to be a mailer that was sent out when the sum pressure of the two tanks fell <600 psi, telling you to swap tanks. Does this no longer exist?

- Sat amp mod and test: on going (Tega)
- Coil driver mod and test: on going (Tega)

- Acromag: almost ready (Yehonathan)

- IDC10-DB9 cable / D2100641 / IDC10F for ribbon in hand / Dsub9M ribbon brought from Downs / QTY 2 for two ends -> Made 2 (stored in the DSUB connector plastic box)
- IDC40-DB9 cable / D2100640 / IDC40F for ribbon in hand / DB9F solder brought from Downs  / QTY 4 for two ends -> Made 4 0.5m cables (stored in the DSUB connector plastic box)

- DB15-DB9 reducer cable / ETMX2+ETMY2+VERTEX16+NewSOS14 = 34 / to be ordered

- End DAC signal adapter with Dewhitening (with DIFF/SE converter) / to be designed & built
- End ADC adapter (with SE/DIFF converter) / to be designed & built

MISC Ordering

• 3.5 x Sat Amp Adapter made (order more DSUB25 conns)
  • -> Gave 2 to Tega, 1.5 in the DSUB box
  • 5747842-4 A32100-ND -> ‎5747842-3‎ A32099-ND‎ Qty40
  • 5747846-3 A32125-ND -> ‎747846-3‎ A23311-ND‎ Qty40
• Tega's sat amp components
  • 499Ω P499BCCT-ND 78 -> Backorder -> ‎RG32P499BCT-ND‎ Qty 100
  • 4.99KΩ TNPW12064K99BEEA 56 -> Qty 100
  • 75Ω YAG5096CT-ND 180 -> Qty 200
  • 1.82KΩ P18391CT-ND 103 -> Qty 120
  • 68 nF P10965-ND 209
• Order more DB9s for Tega's sat amp adapter 4 units (look at the AA IO BOM) 
  • 4x 8x 5747840-4 DB9M PCB A32092-ND -> 6-747840-9‎ A123182-ND‎ Qty 35
  • 4x 5x 5747844-4 A32117-ND -> Qty 25
  • 4x 5x DB9M ribbon MMR09K-ND -> 8209-8000‎ 8209-8000-ND‎ Qty 25
  • 4x 5x 5746861-4 DB9F ribbon 5746861-4-ND -> 400F0-09-1-00 ‎LFR09H-ND‎ Qty 35
• Order 18bit DAC AI -> 16bit DAC AI components 4 units
  • 4x 4x 5747150-8 DSUB9F PCB A34072-ND -> ‎D09S24A4PX00LF‎609-6357-ND‎ Qty 20
  • 4x 1x 787082-7 CONN D-TYPE RCPT 68POS R/A SLDR (SCSI Female) A3321-ND -> ‎5787082-7‎ A31814-ND‎ Qty 5
  • 4x 1x 22-23-2021 Connector Header Through Hole 2 position 0.100" (2.54mm)    WM4200-ND -> Qty5

[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 -->

1. Open V4; apart from a brief pressure spike in PTP2, everything looked ok so we proceeded to
2. Open V1; P2 spiked briefly and then started to drop. Then, Koji suggested that we could
3. Close V4; but we saw P2 increasing by a factor of~ 10 in a few seconds, so we
4. 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.

After the disk system trouble, we could not make the RTS running at the nominal state. A part of the troubleshoot FB1 was rebooted. But the we found that the GPS time was a year off from the current time

controls@fb1:/diskless/root/etc 0$ cat /proc/gps 
1283046156.91
controls@fb1:/diskless/root/etc 0$ date
Thu Sep  2 18:43:02 PDT 2021
controls@fb1:/diskless/root/etc 0$ timedatectl 
      Local time: Thu 2021-09-02 18:43:08 PDT
  Universal time: Fri 2021-09-03 01:43:08 UTC
        RTC time: Fri 2021-09-03 01:43:08
       Time zone: America/Los_Angeles (PDT, -0700)
     NTP enabled: no
NTP synchronized: yes
 RTC in local TZ: no
      DST active: yes
 Last DST change: DST began at
                  Sun 2021-03-14 01:59:59 PST
                  Sun 2021-03-14 03:00:00 PDT
 Next DST change: DST ends (the clock jumps one hour backwards) at
                  Sun 2021-11-07 01:59:59 PDT
                  Sun 2021-11-07 01:00:00 PST

Paco went through the process described in Jamie's elog [40m ELOG 16299] (except for the installation part) and it actually made the GPS time even strange

controls@fb1:~ 0$ cat /proc/gps
967861610.89

I decided to remove the gpstime module and then load it again. This made the gps time back to normal again.

controls@fb1:~ 0$ sudo modprobe -r gpstime
controls@fb1:~ 0$ cat /proc/gps
cat: /proc/gps: No such file or directory
controls@fb1:~ 1$ sudo modprobe gpstime
controls@fb1:~ 0$ cat /proc/gps
1314671254.11

After the reboot daqd_dc was not working, but manual starting of open-mx / mx services solved the issue.

sudo systemctl start open-mx.service
sudo systemctl start mx.service
sudo systemctl start daqd_*

We had the issue of the RT machines rebooting. Once we hooked up the display on c1iscex, it turned out that the IP was not given at it's booting-up.

I went to chiara and confirmed that the DHCP service was not running

~>sudo service isc-dhcp-server status
[sudo] password for controls:
isc-dhcp-server stop/waiting

So the DHCP service was manually restarted

~>sudo service isc-dhcp-server start
isc-dhcp-server start/running, process 24502
~>sudo service isc-dhcp-server status
isc-dhcp-server start/running, process 24502
 

[Paco, Tega, Koji]

Once chiara's DHCP is back, things got much more straight forward.
c1iscex and c1iscey were rebooted and the IOPs were launched without any hesitation.

Paco ran rebootC1LSC.sh and for the first time in this year we had the launch of the processes without any issue.

Attachment 1:
We are pumping the main volume with TP2. Once P1a reached the pressure ~2.2mtorr, we could open the PSL shutter. The TP2 voltage went up once but came down to ~20V. It's close to nominal now.
We wondered if we should use TP3 or not. I checked the vacuum pressure trends and found that the annulus pressures were going up. So we decided to open the annulus valves.

Attachment 2:
The current vacuum status is as shown in the MEDM screenshot.

There is no trend data of the valve status (sad)

[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.

Also deleted the ~50GB error files from ldas to prevent rsync from copying them to nodus again. With the new update to GWsumm, there are new error messages that initially didn't seem to affect the summary pages functionality, but in the extreme case can populated the error files the repeated warnings on the form "Loading: FrSerData", "Loading: FrSerData::n4294967295", "Loading: FrSummary","Loading: FrSerDataLoading: FrSerData" and many more combinations until we get file sizes of the order of ~50GB. So I have updated the checkstatus script to parse the error files and strip out the majority of these error messages. Work is ongoing to get them all.

In light of these large files generation, I decided to look in the summary pages folder to see if there are other large files that we need to keep track of and it turns there are indeed a collection of files in the archive folder that bloats the summary pages on ldas to ~1TB. Luckily these are not synced to nodus so no problem here. However, since the beginning of the year, the archive folders that hold data used for each day's computation have not been cleared. We have a script for doing this but it has not been run for a while now and it only delete archive files for a specific month which is hardcoded to two months from the date the file is run. I have modified the code to allow archive deletion for a range of months so we can clear data from Jan to July. 

[paco]

This morning, I spent some time restoring the jupyter notebook server running in allegra. This server was first set up by Anchal to be able to use the latest nds python API tools which is handy for the calibration stuff. The process to restore the environment was to run "source ~/bashrc.d/*" to restore some of the aliases, variables, paths, etc... that made the nds server work. I then ran ssh -N -f -L localhost:8888:localhost:8888 controls@allegra from pianosa and carry on with the experiment.

[paco, hang, tega]

We started a notebook under /users/paco/20210906_XARM_Cal/XARM_Cal.ipynb on which the first part was doing the following;

• Set up list of excitations for C1:LSC-XARM_EXC (for example three sine waveforms) using awg.py
• Make sure the arm is locked
• Read a reference time trace of the C1:LSC-XARM_IN2 channel for some duration
• Start excitations (one by one at the moment, ramptime ~ 3 seconds, same duration as above)
• Get data for C1:LSC-XARM_IN2 for an equal duration (raw data in Attachment #1)
• Generate the excitation sine and cosine waveforms using numpy and demodulate the raw timeseries using a 4th order lowpass filter with fc ~ 10 Hz
• Estimate the correct demod phase by computing arctan(Q / I) and rerunning the demodulation to dump the information into the I quadrature (Attachment #2).
• Plot the estimated ASD of all the quadratures (Attachment #3)

[paco, hang, tega]

Estimation of open loop gain:

• Grab data from the C1:LSC-XARM_IN1 and C1:LSC-XARM_IN2 test points
• Infer excitation from their differnce, i.e. C1:LSC-XARM_EXC = C1:LSC-XARM_IN2 - C1:LSC-XARM_IN1
• Compute the open loop gain as follows : G(f) = csd(EXC,IN1)/csd(EXC,IN2), where csd computes the cross spectra density of the input arguments
• For the uncertainty in G, dG, we repeat steps (1) to (3) with & without signal injection in the C1:LSC-XARM_EXC channel. In the absence of signal injection, the signal in C1:LSC-XARM_IN2 is of the form: Y_ref = Noise/(1-G), whereas with nonzero signal injection, the signal in C1:LSC-XARM_IN2 has the form: Y_cal = EXC/(1-G) + Noise/(1-G), so their ratio, Y_cal/Y_ref = EXC/Noise, gives the SNR, which we can then invert to give the uncertainty in our estimation of G, i.e dG = Y_ref/Y_cal.
• For the excitation at 53 Hz, our measurtement for the open loop gain comes out to about 5 dB whiich is consistent with previous measurement.
• We seem to have an SNR in excess of 100 at measurement time of 35 seconds and 1 count of amplitude which gives a relative uncertainty of G of 0.1%
• The analysis details are ongoing. Feedback is welcome.

In the weekly meeting, Jordan pointed out that we didn't receive the alert for the low N2 pressure.

To check the situation, I went around the machines and summarized the cronjob situation.
[40m wiki: cronjob summary]
Note that this list does not include the vacuum watchdog and mailer as it is not on cronjob.

Now, I found that there are two N2 scripts running:

1. /opt/rtcds/caltech/c1/scripts/Admin/n2Check.sh on megatron and is running every minute (!)
2. /opt/rtcds/caltech/c1/scripts/Admin/N2check/pyN2check.sh on c1vac and is running every 3 hours.

Then, the N2 log file was checked: /opt/rtcds/caltech/c1/scripts/Admin/n2Check.log

Wed Sep 1 12:38:01 PDT 2021 : N2 Pressure: 76.3621
Wed Sep 1 12:38:01 PDT 2021 : T1 Pressure: 112.4
Wed Sep 1 12:38:01 PDT 2021 : T2 Pressure: 349.2
Wed Sep 1 12:39:02 PDT 2021 : N2 Pressure: 76.0241
Wed Sep 1 12:39:02 PDT 2021 : N2 pressure has fallen to 76.0241 PSI !

Tank pressures are 94.6 and 98.6 PSI!

This email was sent from Nodus.  The script is at /opt/rtcds/caltech/c1/scripts/Admin/n2Check.sh

Wed Sep 1 12:40:02 PDT 2021 : N2 Pressure: 75.5322
Wed Sep 1 12:40:02 PDT 2021 : N2 pressure has fallen to 75.5322 PSI !

Tank pressures are 93.6 and 97.6 PSI!

This email was sent from Nodus.  The script is at /opt/rtcds/caltech/c1/scripts/Admin/n2Check.sh

...

The error started at 11:39 and lasted until 13:01 every minute. So this was coming from the script on megatron. We were supposed to have ~20 alerting emails (but did none).
So what's happened to the mails? I tested the script with my mail address and the test mail came to me. Then I sent the test mail to 40m mailing list. It did not reach.
-> Decided to put the mail address (specified in /etc/mailname , I believe) to the whitelist so that the mailing list can accept it.
I did run the test again and it was successful. So I suppose the system can now send us the alert again.
And alerting every minute is excessive. I changed the check frequency to every ten minutes.

What's happened to the python version running on c1vac?
1) The script is running, spitting out some error in the cron report (email on c1vac). But it seems working.
2) This script checks the pressures of the bottles rather than the N2 pressure downstream. So it's complementary.
3) During the incident on Sept 1, the checker did not trip as the pressure drop happened between the cronjob runs and the script didn't notice it.
4) On top of them, the alert was set to send the mails only to an our former grad student. I changed it to deliver to the 40m mailing list. As the "From" address is set to be some ligox...@gmail.com, which is a member of the mailing list (why?), we are supposed to receive the alert. (And we do for other vacuum alert from this address).

Tega mentioned in the meeting that it could be safer to separate some of nodus's functions from the martian file system.
That's an interesting thought. The summary pages and other web services are linked to the user dir. This has high traffic and can cause the issure of the internal network once we crash the disk.
Or if the internal system is crashed, we still want to use elogs as the source of the recovery info. Also currently we have no backup of the elog. This is dangerous.

We can save some of the risks by adding two identical 2TB disks to nodus to accomodate svn/elog/web and their daily backup.

[Koji, Stephen - updated 30 September]

Cable lengths task - in vacuum cabling for the green section (new, custom for 40m) and yellow section (per aLIGO, except likely with cheaper FEP ribbon cable material) from 40m/16198. These arethe myriad of cables extending from the in vacuum flange to the aLIGO-style on-table Cable Stand (think, for example, D1001347), then from the cable stand to the OMCs.

a) select a position for the cable stand.

 - Koji and I discussed and elected to place in the (-X, -Y) corner of the table (Northwest in the typical diagram) and near the table edge. This is adjacent to the intended exit flange for the last cable.

b) measure distances and cable routing approximations for cable bracket junctions

- Near OMC bracket to the cable stand, point to point = 17.2, routing estimate = 24.4.
- Far OMC bracket to the cable stand, point to point = 20.5, routing estimate = 32.2.

  - Recommendation = 48" for all green section cables (using one length for each OMC, with extra slack to account for routing variation).

c) (outdated - see item (b) and attachment 3) measure distances (point to point) and cable routing approximations for all items.

 +X OMC (long edge aligned with +Y beam axis) (overview image in Attachment 1)

- QPDs to the cable stand, point to point = 12, routing estimate = 20.
- DCPDs to the cable stand, point to point = 25, routing estimate = 32.
- PZTs to the cable stand, point to point = 21, routing estimate = 32.

+Y OMC (long edge aligned with +Y beam axis) (overview image in Attachment 1)

- QPDs to the cable stand, point to point = 16, routing estimate = 23.
- DCPDs to the cable stand, point to point = 26, routing estimate = 38.
- PZTs to the cable stand, point to point = 24, routing estimate = 33.

Cable stand to flange (Attachment 2) (specific image in Attachment 2)

- point to point = 35, routing estimate = 42

  - Recommendation = 120" for all yellow section cables, per Koji's preferences for zigzag cable routing on stack and coiling of slack.

I finally got the modbus part working on chiara, so we can now view the temperature data on any machine on the martian network, see Attachment 1. 

I also updated the entries on /opt/rtcds/caltech/c1/chans/daq/C0EDCU.ini, as suggested by Koji, to include the SensorGatway temperature channels, but I still don't see their EPICs channels on https://ldvw.ligo.caltech.edu/ldvw/view. This means the channels are not available via nds so I think the temperature data is not being to be written to frame files on framebuilder but I am not sure what this entails, since I assumed C0EDCU.ini is the framebuilder daq channel list.

When the EPICs channels are available via nds, we should be able to display the temperature data on the summary pages.

Came in at ~ 9 PT this morning to find the IFO "down". The IMC had lost its lock ~ 6 hours before, so at about 03:00 AM. Nothing seemed like the obvious cause; there was no record of increased seismic activity, all suspensions were damped and no watchdog had tripped, and the pressure trends similar to those in recent pressure incidents show nominal behavior (Attachment #1). What happened?

Anyways I simply tried reopening the PSL shutter, and the IMC caught its lock almost immediately. I then locked the arms and everything seems fine for now .

So we agreed that the RTNs points on the c1auxex Acromag chassis should just be grounded to the local Acromag ground as it just needs a stable reference. Normally, the RTNs are not connected to any ground so there is should be no danger of forming ground loops by doing that. It is probably best to use the common wire from the 15V power supplies since it also powers the VME crate. I took the spectra of the ETMX OSEMs (attachment) for reference and proceeding with the grounding work.

I was showing some green laser locking to Tega, I noticed that changing the PZT sliders of M1/M2 angular position on Xend had no effect on locked TEM01 or TEM00 mode. This is odd as changing these sliders should increase or decrease the mode-matching of these modes. I suspect that the controls are not working correctly and the PZTs are either not powered up or not connected. We'll investigate this in near future as per priority.

Anchal mentioned it would be good to put more details about how I arrived at the values needed to configure the modbus drive for the temperature sensor, since this information is not in the manual and is hard to find on the internet, so here is a breakdown.

So the generic format is:

drvAsynIPPortConfigure("<TCP_PORT_NAME>","<UNIT_IP_ADDRESS>:502",0,0,1)
modbusInterposeConfig("<TCP_PORT_NAME>",0,5000,0)
drvModbusAsynConfigure("<PORT_NAME>","<TCP_PORT_NAME>",<slaveAddress>,<modbusFunction>,<modbusStartAddress>,<modbusLength>,<dataType>,<pollMsec>,<plcType>)

which in our case become:

drvAsynIPPortConfigure("c1pemxendtemp","192.168.113.240:502",0,0,1)
modbusInterposeConfig("c1pemxendtemp",0,5000,0)
drvModbusAsynConfigure("C1PEMXENDTEMP","c1pemxendtemp",0,4,199,2,0,1000,"ServerCheck")

As can be seen, the parameters of the first two functions "drvAsynIPPortConfigure" and "modbusInterposeConfig" are straight forward, so we restrict our discussion to the case of third function "drvModbusAsynConfigure". Well, after hours of trolling the internet, I was able to piece together a coherent picture of what needs doing and I have summarised them in the table below.

drvModbusAsynConfigure

Once the asyn IP or serial port driver has been created, and the modbusInterpose driver has been configured, a modbus port driver is created with the following command:

drvModbusAsynConfigure(portName,                # used by channel definitions in .db file to reference this unit)
                       tcpPortName,             # reference to portName created with drvAsynIPPortConfigure command
                       slaveAddress,            # 
                       modbusFunction,          # 
                       modbusStartAddress,      # 
                       modbusLength,            # length in dataType units
                       dataType,                # 
                       pollMsec,                # how frequently to request a value in [ms]
                       plcType);                #

Useful links

https://nodus.ligo.caltech.edu:8081/40m/16214

https://nodus.ligo.caltech.edu:8081/40m/16269

https://nodus.ligo.caltech.edu:8081/40m/16270

https://nodus.ligo.caltech.edu:8081/40m/16274

http://manuals.serverscheck.com/InfraSensing_Sensors_Platform.pdf

http://manuals.serverscheck.com/InfraSensing_Modbus_manualv5.pdf

https://community.serverscheck.com/discussion/comment/7419#Comment_7419

https://wiki-40m.ligo.caltech.edu/CDS/SlowControls

https://www.slac.stanford.edu/grp/ssrl/spear/epics/site/modbus/modbusDoc.html#Creating_a_modbus_port_driver

https://github.com/riptideio/pymodbus

https://en.wikipedia.org/wiki/Modbus

https://deltamotion.com/support/webhelp/rmctools/Communications/Ethernet/Supported_Protocols/Ethernet_Modbus_TCP.htm

[Tega, Anchal, Paco]

After talking to Anchal, it was made clear that chiara is not the place to host the modbus service for the temperature sensors. The obvious machine is c1pem, but the startup cmd script loads c object files and it is not clear how easy it would integrate the modbus functionality since we can only login via telnet, so we decided to instead host the service on c1susaux. We also modified the /etc/motd file on c1susaucx which displays the welcome message during login to inform the user that this machine hosts the modbus service for the temperature sensor. Anchal plans to also document this information on the temperature sensor wiki at some point in the future when the page is updated to include what has been learnt so far.

We might also consider updating the database file to a more modern way of reading the temperature sensor data using FLOAT32_LE which is available on EPICs version 3.14 and above, instead of the current method which works but leaves the reader bemused by the bitwise operations that convert the two 16 bits words (A and B) to IEEE-754 32-bit float, via 

field(CALC, "(A&D?(A&C?-1:1):0)*((G|A&E)*J+B)*2^((A&D)/G-F)")

where 

   field(INPA, "$HiWord")
   field(INPB, "$LoWord")
   field(INPC, "0x8000")   # Hi word, sign bit
   field(INPD, "0x7F80")   # Hi word, exponent mask
   field(INPE, "0x00FF")   # Hi word, mantissa mask (incl hidden bit)
   field(INPF, "150")      # Exponent offset plus 23-bit mantissa shift
   field(INPG, "0x0080")   # Mantissa hidden bit
   field(INPJ, "65536")    # Hi/Lo mantissa ratio
   field(CALC, "(A&D?(A&C?-1:1):0)*((G|A&E)*J+B)*2^((A&D)/G-F)")
   field(PREC, "4")

as opposed to the more modern form

field(INP,"@asyn($(PORT) $(OFFSET))FLOAT32_LE")

/var on fb1 filled up today, which caused all sorts of CDS issues.  I found out about the problem by reading the logs of the services that were having trouble running, in which they complained about not being able to write to disk.  I looked at the filesystem status with 'df' and noticed that /var was full, which is where applications write temporary data, and will always cause problems if it's full.

I tracked the issue down to multiple multi-gigabyte log files: /var/log/messages and /var/log/messages.1.  They were full of lines like this one:

Seems like something related to the gpstime kernel module?

Anyway, I deleted the log files for now, which cleared up the space on /var.  Things should be back to normal now, until the logs fill up again...

Yehonathan noticed today that the silver plated hardware on the assembled SOS towers had some pretty severe discoloration on it. See attached picture.

These were all brand new screws from UC components, and have been sitting on the flow bench for a couple months now. I believe this is just oxidation and is not an issue, I spoke to Calum as well and showed him the attached picture and he agreed it was likely oxidation and should not be a problem once installed.

He did mention if there is any concern from anyone, we could take an FTIR sample and send it to JPL for analysis, but this would cost a few hundred dollars.

I don't believe this to be an issue, but it is odd that they oxidized so quickly. Just wanted to relay this to everyone else to see if there was any concern.

Jonathan Hanks pointed me to this fix to the gpstime kernel module that was unfortunately put in after the 3.4 release that we're currently using:

https://git.ligo.org/cds/advligorts/-/commit/6f6d6e2eb1d3355d0cbfe9fe31ea3b59af1e7348

I hacked the source in place (/usr/src/gpstime-3.4/drv/gpstime/gpstime.c) to get the fix, and then rebuilt the kernel module with dkms :

sudo dkms uninstall gpstime/3.4
sudo dkms install gpstime/3.4

I then stopped daqd_dc, unloaded gpstime, reloaded it, restarted daqd_dc.  The messages are no longer showing up in /var/log/messages, so I think we're ok for the moment.

NOTE: the fix will be undone if we for some reason reinstall the advligorts-gpstime-dkms package.  There shouldn't be a need to do that, but we should be aware.  I'm discussing with Jonathan if we want to try to push out a new debian package to fix this issue...

Yup this is OK. No problem.

For the past couple of days the 0.1 to 0.3 Hz RMS seismic noise along BS-X has increased. Attachment 1 shows the hour trend in the last ~ 10 days. We'll keep monitoring it, but one thing to note is how uncorrelated it seems to be from other frequency bands. The vertical axis in the plot is in um / s

[Tega, Paco, Anchal]

We attempted to reboot fb1 daqd today to get the new temperature sensor channels recording. However, the FE models got stuck, apparantely due to reasons explaine din 40m/16325. Jamie cleared the /var/logs in fb1 so that FE can reboot. We were able to reboot the FE machines after this work successfully and get the models running too. During the day, the FE machines were shut down manually and brought back on manually, a couple of times on the c1iscex machine. Only change in fb1 is in the /opt/rtcds/caltech/c1/chans/daq/C0EDCU.ini where the new channels were added, and some hacking was done by Jamie in gpstime module (See 40m/16327).

Looks like this increase is correlated for BS/EX/EY. So it is likely to be real.

Comparison between 9/15 (UTC) (Attachment 1) and 9/10 (UTC) (Attachment 2)

{Yehonathan, Paco}

We turned off the ETMX watchdogs and OpLevs. We went to the X end and shut down the Acromag chassi. We labeled the chassi feedthroughs and disconnected all the cables from it.

We took it out and tied the common wire of the power supplies (the commons of the 20V and 15V power supplies were shorted so there is no difference which we connect) to the RTNs of the analog inputs.

The chassi was put back in place. All the cables were reconnected. Power turn on.

We rebooted c1auxex and the channels went back online. We turned on the watchdogs and watched the ETMX motion get damped. We turned on the OpLev. We waited until the beam position got centered on the ETMX.

Attachment shows a comparison between the OSEM spectra before and after the grounding work. Seems like there is no change.

We were able to lock the arms with no issues.

It was known that the Y end ALS PZTs are not working. But Anchal reported in the meeting that the X end PZTs are not working too.

We went down to the X arm in the afternoon and checked the status. The HV (KEPCO) was off from the mechanical switch. I don't know this KEPCO has the function to shutdown the switch at the power glitch or not.
But anyway the power switch was engaged. We also saw a large amount of misalignment of the X end green. The alignment was manually adjusted. Anchal was able to reach ~0.4 Green TRX, but no more. He claimed that it was ~0.8.

We tried to tweak the SHG temp from 36.4. We found that the TRX had the (local) maximum of ~0.48 at 37.1 degC. This is the new setpoint right now.

Ordered compoenents are in.

- Made 36 more Sat Amp internal boards (Attachment 1). Now we can install the adapters to all the 19 sat amp units.

- Gave Tega the components for the sat amp adapter units. (Attachment 2)

- Gave Tega the componennts for the sat amp / coil driver modifications.

- Made 5 PCBs for the 16bit DAC AI rear panel interface (Attachment 3)

RIO Planex 1064 Lasers in the south cabinet

Property Number C30684/C30685/C30686/C30687

It happened again. Defrosting required.

Put outside.

We can now view the minute trend of the temperature sensors under the PEM tab of the summary pages. See attachment 1 for an example of today's temperature readings. 

I gave some of the data analysts a look around because they asked and nothing was currently going on in the 40m. Nothing was changed.

Fridge brought back inside.

The Incredible Melting Man!