Now that the commissioners start to use CO2Y I want it to be obvious if it trips.
Kiwamu, Nutsinee
In order to understand the characteristic of the COY rotation stage I ran Kiwamu's script with TCS CO2 channels asking the rotation stage to turn to random angles. The result is attached below. The first plot shows that CO2Y rotation stage works 85%-93% of the time (out of 300 samples). Changing the rotational state speed by 50% didn't make much difference (if not worse). The nominal speed is 100%. When the rotation stage didn't go to the requested angle the difference is always roughly 30 degree. In comparison I attached the second plot showing data from CO2X rotation stage that has quite a nice behavior. The requested angles and measured angles agree within half a degree (out of 100 samples).
It might be interesting to see the measured power for each of these as well. I would probably trust that more as an indication of the measured angle than the reading from the stage.
Below you will find the plot measured CO2 power vs. requested angle. Notice that CO2X power follows the sinusoidal pattern quite nicely while CO2Y power is ~30 degree phase delay from the main sine wave when the rotation state is busted.
John, Chandra Connected aux pumping carts to the following annuli: 1. HAM 7/8, with secondary turbo Pressure: 3.4e-5 Torr 2. HAM 11/12, with secondary turbo Pressure: 9.5e-5 Torr 3. HAM 9, no secondary turbo Pressure: 7.0e-4 Torr Still need to connect BSC4 annulus. Two annuli systems are leaking, based on the attached plot of diagonal gauge PT-140. Leak rate (O) e-3 Torr-l/s.
Tuesday evening: all three pressures on annuli are now low e-5 Torr range. I closed each turbo valve individually to see if pressure would rise in diagonal (on PT-140). No observed changes in pressure over 10 min time span for each. We have greatly reduced the leak rate by reducing pressure in the annuli.
The lock out/tag out for the HPO power supplies was removed. Both the internal and external shutters of the HPO had their flags replaced. The position of the flags were also adjusted so that the magnetic position sensor was triggered when the shutter was opened/closed. TwinCAT uses the position sensor for animation on the user screen. Each of the four laser heads was powered up, one at a time and with 5 amp increments up to the nominal pump power (50 A). No problems were observed with the fibre bundles. The diode currents were set back to zero. As we were closing up, a small pool of water was observed on the base plate. Fortunately none of it was spraying anywhere. The source was traced to the flow sensor in head 3. It was removed, its PTFE tape redone and re-installed. No leak was observed for a period of time afterwards but this should be monitored and kept in mind if the crystal chiller keeps complaining about low water level or a flow sensor problem. If the front end laser trips out and you do not know how to bring it back on line, PLEASE ASK or get someone who knows how to do it. Jason, Peter
Accidentally posted this in the wrong log entry! Corrected. All three pressures on annuli are now low e-5 Torr range. I closed each turbo valve individually to see if pressure would rise in diagonal (on PT-140). No observed changes in pressure over 10 min time span for each. We have greatly reduced the leak rate by reducing pressure in the annuli.
I reset the 35W FE power watchdog at 20:52 UTC (13:52 PDT).
Attached is a plot of the high power oscillator diode currents prior to its shutdown over two years ago. These are the currents that the high power oscillator will be restored to. DB1 51.3 A DB2 49.7 A DB3 50.8 A DB4 49.0 A
ITMY ring heater was left on for an overnight measurement. The upper and lower segments of the ring heater were set to 1 W (i.e. 2W in total). The interferometer is aligned but in the down state. I started the HWS codes on h1hwsmsr because they were not running. I have not updated the reference images for the HWS codes this time. Therefore they use whatever the reference images that are in ~/temp/. The ring heater will be automatically switched off at around 6 am in local time by a script running on opsws4.
The HWS code should have been running in a single tmux session containing two windows. Clearly this is too easy to circumvent. I'll talk to Jamie about seeing if we can get this set up as a daemon process instead with the new version of the code.
JimB and I are working on this issue at the moment. We are trying to get rid of tmux sessions by implenting monit. As of yesterday, we succeeded in running the hartman codes under the managmenet of monit. The implementation is still underway and about 80% done at the moment.
We are having a trouble with the CO2 Y laser where every time when we request an angle to the rotation stage, it trips the laser for unknown reason. According to the MEDM screen, "RTD/IR SENS. ALARM" turns in red when we request an angle to the rotation stage. We needed to hit the gate button at the floor in order to untrip the laser. If we do not change the rotation stage angle, the laser seems to stay on,
We need help from experts.
Fixed.
It was loosely connected D-sub calbes. I went to the floor and was going to inspect the controller box as suggested by Alastair. However, it turned out that tightening up all the D-sub cables on the front panel of the controller box apparently fixed the problem. I did not even try to reproduce the issue.
Jenne, Sheila, Kiwamu, Hang, Stefan
We tried to monitor the AS WFS gains during powerup. However, we didn't see any sign flips. Nevertheless, a combination of SOFT and SCR1 loops ran away anyway.
On the next attempt we again observe the onset of a 0.4Hz oscillation in pitch, which, depending on alignment, starts around 13W-15W, and grows until lock-break.
Jenne tried to move the soft offsets around to see whether there are alignments that are less suceptible to the 0.4Hz oscillation - not much luck.
Looking at the OPLEVs we noticed that mostly the xarm pitch is moving during power-up (but too slow for radiation pressure effects). Note that during this the soft loop error signals are kept zero, which suggests some non-linearity in the X QPDs.
One last attempt: We opened the SOFT loops, then went to 10W. We still get our "favorite" oscillation. We'll look at some lockloss plots when we're more awake.
Prompted in part by the day that the vacuum team needed an extra TV for remote medm screen monitoring, we have thought a bit about where we really want some of our FOMs displayed, and which ones belong where.
The range integrand is useful, but perhaps not something that we need to be watching in realtime. I have promoted the ASC control signals (previously on the top monitor of video0) to the place where the range integrand was, at the bottom of nuc6. Since I can't directly access the bottom screen, the striptools are kind of mushed right now, but if someone can get them nicely displayed on nuc6, that'd be great. These are the same {userapps}/isc/h1/scripts/[PITCH or YAW]_ASC_CONTROL_SIGNALS.stp strip tool templates that were formerly on video0.
Rather than putting the range integrand on video0, I have put the ASC error signals up on video0, since we occassionally want to see these. The color scheme is the same as the control signals, although the backgrounds are slightly different colors to indicate that they're not quite the same (err vs. ctrl signals). We may need to think more on the y-scales - right now I have them optimized for in-lock, so they're rail-to-rail while we're unlocked. We may want to zero the input matrices in the DOWN state and then re-write them before use, to make these strip tools less crazy. These templates now live in {userapps}/isc/h1/scripts/[PITCH or YAW]_ASC_ERROR_SIGNALS.stp.
JimB will update the labels on the screen capturing webpage in the morning to reflect these changes. Thanks Jim!!
The control room screen shot web page has been modified, and the nuc6 computer has been configured to automatically start the strip tools when rebooted.
Kiwamu, Jenne, Stefan
With the ASC fully engaged at 2W, we wanted the see how it behaves at higher powers. Up to 10W the behavior was fine, then we started loosing recycling gain.
During this sequence we dithered BS in pitch and monitored its sensor, ASB36Q_PIT. We monitored this channel because this was running away in the O1 configuration (alog ). However it was not the culprit.
Posted below are the past 10 day trends. The WeeklyXtal trends reflect the ongoing "beginning of the end" of th FE amplifier diodes with a confusing upwards twist (most recently) which I've queried Peter about as his last aLog also shows this ( https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=26154 ) but he made no comment about it. The WeeklyEnv trends shows a seemingly sizeable(?) drop in Relative Humidity between the 14th and the 20th. Curious that the curve is practically identical for the Laser and Anteroom as it is for the Diode and Chiller rooms given the distance between them.
Today we noticed that there were some unidentified bright dots on the ITMX green camera (cam22) which had not existed before. The positions of the dots were found to be functions of the alignment of the ITMX compensation plate for some reason. We temporarily applied a large offset (-530 urad in yaw) on the compensation plate to minimize the effect on the centroid fitting. We tried moving the dots by moving the large suspended optics, but none of them showed dependencies. We have no idea why we started having thees dots. We will try using the camera as it is since the dots seem to be insensitive to the arm cavity alignment.
The compensation plates seem to be responsible for the etalon effect. The green spots disappear, when the green beam is shuttered at the end.
Updated the camera configuration files (centroid and radius) and reference positions. Attached are snapshots and the config files.
