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=== Type B ===
Report

 * By comparing pictures and the 3D-CAD Hirata-san realized the BS large frame is missing some beams. Saito-san remembered Mirapro was not able to put them in place because of a conflict with the clean booth pillars. He has already requested Mirapro to redesign the beams. Let's hope to install them before O4.
 * On Sunday we did hammering test on SR2 chamber and on the duct between SR2 and SR3. Apparently the IFO lock endured the hammering test but lost lock when we walked in front of the oplev. Looking more carefully to the data is required in order to identify the trigger of the event. (See klog entry [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=13884|13884]].)
  * The channel '''K1:VIS-SR2_TM_OPLEV_LEN_YAW_OUTPUT '''went from -10 ndu to -74 ndu, which is out of linear range (-50 ndu to 50 ndu is the linear range).
  * TM-Y control actuation saturated.
  * Upon request from Yokozawa-san I didn't move the QPD because he wanted the commissioners to do it in order to recover the main IFO at the same time.
  * Lack of communication on my part created a problem for commisioners (klog entry [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=13891|13891]]). Later Yokozawa-san and Nakano-kun moved the QPD and changed the TM-Y filter.
  * It didn't seem to be necessary for the IFO but it would be good to check oplev diagonalization again if there's a chance. The oplev seems to be delicate.
 * I finished writing the oplev digonalization procedure for the Type-B suspensions.
  * Type-B: see [[http://gwwiki.icrr.u-tokyo.ac.jp/JGWwiki/KAGRA/Subgroups/VIS/OpsManual/OpLev/TypeB/|oplev page]] in the wiki.
  * Type-A: see klog entry [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=10786|10786]]. (Just a remainder.)
 * I offloaded coil-magnet actuators onto fishing rods or IM picomotors.
  * BS IP: F0 and F1 fishing rods are already at their limit (klog entry [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=13927|13927]]).
  * SR3 IP (klog entry [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=13928|13928]]).
  * SR2 F0 and F1: those fishing rods don't seem to have any problem (klog entry [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=13930|13930]], [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=13935|13935]]).
  * Fishing rod information can be written in the [[http://gwwiki.icrr.u-tokyo.ac.jp/JGWwiki/KAGRA/Subgroups/VIS/OpsManual/FishingRods/|VIS Fishing Rod wiki page]]. (Just a remainder.)

Report

 * The hammering test made by Yokozawa-san revealed that the BS large external frame is very sensitive to disturbances (klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=13603|13603]]). "Very very very" gentle touching produces saturation of the IP actuators (klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=13661|13661]]). I don't remember the other frames and suspensions being as delicate. After O3 I aim to reproduce the effect in the BS suspension and check the SR ones. We should notify Mirapro in case the situation is particularly bad in case they believe adjustment to the frame screws and bolts is required.
 * Temperature change in BS clean both: it has drifted from '''23.7 °C to 22.9 °C in 60 days''' (klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=13663|13663]]). Such a large change has produced an increase in the feedback signals of the IP coils. Particularly uncomfortable is H2 actuation which reaches -18,500 counts. For H2 I changed the limit from 20,000 to 25,000 counts. I asked Miyoki-san about what was the plan for O4 and he suggested VIS should take care. Using [[http://www.globallab.com/html/english/product01.html?PHPSESSID=2863f3680fdb5c24eebe362eb39ef9a0|heating jackets]] was suggested.
 * During the long weekend Michimura-kun checked oplev diagonalization in SRM and balanced the TM coils in all SR suspensions (klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=13764|13764]]).
  * Initially there was a confusion with some signs because he was using the oplev far out of range and because the coil-magnet actutors in the BS are at the front and not at the back of the optic as in the SRs. Nevertheless, the situation was clarified.
  * His diagonalization procedure yielded similar results to Terrence's, so he trusted the work previously done and left the other Type-B oplevs as they are. We still should check just to make sure the earthquake didn't change anything significantly, but it doesn't seem to be an urgent task for now.
  * On Monday he centered the SR2 and SRM QPDs (along with all PR ones). (klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=13764|13764]].)
  * He wrote a Python script to balance the TM coils (klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=13739|13739]]) based on the method used by Ushiba-san on PR3 (klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=13614|13614]]). It actuates each TM coil separately at a particularly frequency and uses the transfer functions to yaw in order to quantify the difference among actuators. It then uses the value in H2 to normalize the the other three values.

Report for the week 16-12-2019

 * Limit switch for IM picomotors: last meeting there were concerns about the pin 5 of the in-air cable being connected to shield and the case. The solution would be to use an unshielded cable. See updated slides in this [[https://www.dropbox.com/s/dh54u2hat9w8jzo/Limit_switch_IM.pdf?dl=0|link]].
 * SR2 neighborhood clean room survey.
  * I didn't finish this week surveying the clean room. I realized I need more information about the position of the handrails in the 2nd floor. I will measure that on the 14th of January. If the analysis is required earlier another person can take over. I left some files in Dropbox [[https://www.dropbox.com/sh/dsbdp5rrxt5sk5b/AABLaas7fA9dWnvAx40zYnR0a?dl=0|here]].
  * There's not much space available to extend the clean room by a lot without blocking valuable access into the +X arm. We will likely require to set the oplev optics outside of the clean booth.
 * Type-B and Type-Bp oplve survey: I went to the tunnel and took a look but, as expected, important features are hidden under aluminium foil covers. I will collect 3D CAD models from the main components.
 * I left a very humble TO DO list for commissioning [[http://gwwiki.icrr.u-tokyo.ac.jp/JGWwiki/KAGRA/Subgroups/VIS/TypeB/ToDo|here]]. I will do this when I come back depeding on the commissioning priorities. Nevertheless, in case anyone wants to do it, please feel free.

=== Plan for next week ===
Report for the week 09-12-2019

 * Shoda-san modified the real-time model to implement Terrence Method for ASC control strategy. See klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=12097|12097]].
 * On Monday I tested a script for the oplev diagonalization procedure based on Terrence's work. After the test I realized it required corrections and I need to use the suspension again. The writing of the proceedure is ongoing.
 * On Tuesday I measured the space available at the +X side of the SR2 vacuum chamber. Using the original orientation of the assembly farme there would be 17 cm between the large outer frame and the assembly frame, whereas on the original assembly place there were about 34 cm. It wouldn't be possible to stand. See klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=12041|12041]]. Nevertheless, if we rotate the frame by 90 degrees it seems possible to have more space. See klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=12065|12065]].
 * In the context of SRM bottom filter repairs, I checked whether the SR chambers have access apertire at the Bottom Filter level like the BS chamber has. They don't. See klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=12117|12117]]. All they have is 20 cm flanges for viewports at the +Y and -Y sides. This may be a problem if we aim to fix the bottom filter without taking the suspension out of the chamber. The plan we had thought was to try to access the bottom filter using the chamber door and try to insert the fibre optic camera throught the holes for locking the keystone. With the small aperture we can likely stick in one arm only.
 * I designed a rough version of the limit switch for IM picomotors. See this [[https://www.dropbox.com/s/dh54u2hat9w8jzo/Limit_switch_IM.pdf?dl=0|link]].

=== Plan for next week ===
 * Compile and install SR real-time models.
 * People have begun to modify or turn off filters which are supposed to be off in OBSEVATION state, maybe I should aim to design the bandpass filters and then implement the Guardian OBSERVATION state.

==== Vacation/Travel Info ====
 * ~-~-Friday next week late in the afternoon we have the KAGRA ceremony. -~

=== Type B ===
Report for the week 23-09-2019

 * I modified the real-time model in order to accomodate bandpass fillters and new DAQ channels. See [[http://gwwiki.icrr.u-tokyo.ac.jp/JGWwiki/http://klog.icrr.u-tokyo.ac.jp/osl/?r=11788|11788]].
  * For the most part I used the same scheme as Type A.
  * As agreed in the previous meeting I added a matrix ramp switch in order to transit from velocity damping to bandpass filters.
  * The medm screen was modified accordingly.
  * I realized yesterday I hadn't added a monitor for the output of the new filters banks in the EUL basis. It's been added to the real-time model, it compiles but still has to be installed.
  * Real-time models for SR suspensionsmust be compiled and installed.
 * Together with Terrence I modified vistools in order to generate functions to manipulate added filter banks. See [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=11788|11788]].
  * The future of vistools looks quite gray (the code is complicated, not commented and we don't know how to manipulate matrix switches). Some will likely be in regular Guardian.
  * I began adding code for the OBSERVATION state in a draft file.
 * There was an agreement with Okutomi-san to change Type B medm screens for something more illustrative of the signal paths.
 * The temperature in the BS area has increased. It's been lately between 23.7 and 23.8 degrees. The actuation on the top filter used to be -23,000 counts and is now -13,500 counts.

 * Yamada-kun and Yokozawa-san measured transfer functions from BS to DARM and calculated the noise contribution. See [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=11676|11676]], [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=11724|11724]], [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=11707|11707]].
  * The results are affected by an error in the calibration and are yet to be corrected.
  * The contributions of TM_DAMP_L and TM_DAMP_Y were considered to be high. These filters are supposed to be off in OBSERVATION state. See this [[http://klog.icrr.u-tokyo.ac.jp/osl/uploads/11748_20191125213530_bstodarmbeforeimyrolloff.png|plot]].
  * These filters were rolled-off and the a new estimation was calculated. See this other [[http://klog.icrr.u-tokyo.ac.jp/osl/uploads/11748_20191125213851_bstodarmafterimyrolloff.png|plot]].
  * The roll-off of TM_DAMP_Y was conservative.
 * Ushiba-san turned off BS TM-L DAMP filter for the FPMI state ([[http://klog.icrr.u-tokyo.ac.jp/osl/?r=11783|11783]]). It may have been affecting the sensitivity.
 * For the purposes of ASC the diagonalization of the TM actuation with respect to the oplev was removed by commissioners and replaced by their own coil balancing and drivealign diagonalization. I couldn't find a klog for this.

=== Plan for next week ===
 * Compile and install SR real-time models.
 * People have begun to modify or turn off filters which are supposed to be off in OBSEVATION state, maybe I should aim to design the bandpass filters and then implement the Guardian OBSERVATION state.

==== Vacation/Travel Info ====
 * ~-~-Friday next week late in the afternoon we have the KAGRA ceremony. -~

==== Report for the week 23-09-2019 ====
 * ~-Terrence modified the real-time model in order to accomodate hierarchical actuation from the interferometer sensing and control system (ISC). The modified model has not been installed. See klog entry [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=10692|10692]]. -~
 * ~-In previous meetings it was reported there was a problem with the medm screen or real-time model in the components related to IP LVDT correction with the seismometer signal. In reality a trivial operation was still required. The apparent problem has been fixed now and we can proceed to implement the sensor correction in SR2 when we have the time. -~

==== Plan for next week ====
 * ~-If we have the time it would be good to implement the sensor correction at least in the BS and test it in bad weather conditions. -~
 * ~-Commit the changes that Terrence made to the real-time model. -~

==== Vacation/Travel Info ====
 * ~-Friday next week late in the afternoon we have the KAGRA ceremony. -~

=== Type B ===
==== Report for the week 13-09-2019 ====
 * ~-In previous weeks we identified injected noise into the SR3 IM from the oplev (klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=10262|10262]]). On Monday I put notches at various frequencies where there were peaks (klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=10423|10423]]). This procedure seems to work but it's tedious and we should do it in an as-needed depending on the impact of each peak in the interferometer signal. -~
 * ~-Shoda-san and Terrence began been working in IM-L to IM-P and IM-Y filters (klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=10505|10505]]). -~
 * ~-In a previuos week I modified the SR2 real-time model in order to do LVDT correction with the seismometer signals. This week was mainly troubleshooting and preparation: * We found a couple of errors in the real-time model (klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=10460|10460]], [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=10509|10509]]). -~
  * ~-Miyo-kun added ati-aliasing filter at the output of the PEM real-time model before the Dolphin network. -~
  * ~-An integrator is needed for the seismometer signal in order to get a displacement. However, the automatically generated medm screen points to a different filter bank (klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=10510|10510]]). This hasn't been fixed yet. -~
  * ~-Still, I measured transfer functions from seismometer on the ground to IP LVDT in FLOAT state, data which can be corrected (klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=10510|10510]]). -~

 * ~-In SR2 the cables connecting the BIO output from the coil drivers to the DIO card inside the I/O chassis were connected in a wrong way. I fixed them (klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=10464|10464]] and [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=10508|10508]]). -~

=== Type B ===
==== Report for the week 02-09-2019 ====
 * ~-Shoda-san implemented new low frequency filters for the IMs using the oplev signals (e.g. klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=10355|10355]]). -~
 * ~-With PEM team on Monday 2nd of September we put accelerometers on the two SR3 oplev platforms and on the large frame (klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=10262|10262]]): -~
  * ~-Above 10 Hz the coherence of the oplev readings with the upper platform accelerometer is high in several regions. -~
  * ~-It was possible to identify injected oplev noise into the suspension by looking at the coherence between one of the accelerometers and the IM, including large peaks between 16 and 18 Hz. -~
  * ~-There's more information in the diaggui file which hasn't been analyzed. -~
 * ~-On Tuesday we moved SR2 and SRM oplev tilt QPDs to sensible positions after the commissioning team re-aligned the interferometer (klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=10291|10291]]). -~
  * ~-I checked the OSEMs position and V2 is in an uncomfortable position: only 140 um from the end of linear range. -~
  * ~-Although until now I checked the position using the calibration information the OSEM flag has been in a nearby position for since the end of May (klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9028|9028]]). -~
  * ~-Due to a problem with the BF keystone, the clerance in the other direction is 140 um. -~
  * ~-We decided to keep the keystone in the current position because it hasn't created any problems so far. -~
 * ~-Nakano-kun reported the BS was moving too much in yaw. I did some measurement and noticed the inertial damping was injecting noise below 100 mHz (klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=10354|10354]]). At 50 mHz there's even a feature 2.4 times larger with inertial damping. We should just turn the inertial damping off. It also happens that according to klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9991|9991]], it is not working so effectively in reducing the integrated RMS. -~
 * ~-Last week I modified the real-time model to enable IP LVDT correction and feedforward with seismometer signals on the ground. On Thursday I worked inthe MEDM screen modification. -~
 * ~-Terrence updated Guardian after a report from Shoda-san concerning SR2: Guardian was not tripping when the GAS filter coil driver hardware watchdog tripped (klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=10352|10352]]). However, after the modification we realized of an additionl problem: in a situation in which the TM coil driver should trip, the GAS filter coil driver trips instead. -~

==== Plan for next week ====
 * ~-Finish the MEDM screen modification, install the real-time model and begin setting the LVDT correction with the seismometer signal. -~
 * ~-In order to minimize the injection of ground motion with the oplev, roll-off the oplev signal before it's used by any filter. * Use a cutoff frequency of about 8 or 9 Hz. -~
  * ~-In order to assess the amount of oplev control noise, ask Yokozawa-san to leave the accelerometer at the oplev upper platform in order to measure its coherece of the IM degrees of freedom. -~

 * ~-Roll-off the GAS DC control filters in order to reduce the control noise in the observation frequency band. -~
 * ~-Do we need to extend the GAS DC control filters to the micro-seismic region? -~

==== Report for the week 26-08-2019 (Written by Fabian) ====
 * ~-Shoda-san improved the SR3 optic pitch filter (klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=10152|10152]], [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=10217|10217)]]. -~
 * ~-For the SR3 optic Enomoto-kun implemented an integrator filter with UGF above the micro-seismic (klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=10014|10014]]). This filter used the oplve signal. -~
  * ~-It works well, but it requires a set-point, which is currently set at the IM level (for IM DC control) not at the optic level. -~
  * ~-A clear and clean implementation requires moving the set-point to the optic level and then take the error signal to the IM. -~
 * ~-Nakano-kun modified the SR2 optic set-point to a place which is not so suitable for the oplev. We will move the QPD on Monday. -~
 * ~-I modified the SR2 tower real-time model to allow for LVDT correction and feedforward with seismometer. * I had to modify the PEM real-time model to connect the seismometer channels to the Dolphin network. -~
  * ~-Both models compile and I'm currently modifying the medm screen. -~

 * ~-Performance report * There was a typhoon before the F2F meeting and this week we have had bad weather, in both cases there was an increase of the micro-sesmic activity. -~
  * ~-During the typoon we saw a large peak at 150 mHz and this week we saw a peak a large peak at 60 mHz. -~
  * ~-With bad weather Type B suspensions' optic motion (upper limit) were above the requirement in TM-L displacement and velocity: BS [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=10046|10046]], SR2 [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=10052|10052]], SR3 [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=10056|10056]], SRM [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=10067|10067]]. -~
  * ~-Nevertheless, in days with good weather the suspensions behave mostly well in ALGNED and FLOAT states: BS [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9697|9697]], SR2 [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9703|9703]], SR3 [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9702|9702]], SRM [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9704|9704]]. -~
  * ~-I also found the vertical ground motion induces motion in TM-Y and TM-P, but even with bad weather the motion remain below the requirement. -~

 * ~-With this bad weather I was able to measure transfer functions from the ground to (klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=10170|10170]]). -~

==== Plan for the week 02-09-2019 ====
 * ~-On Monday I will work with Yokozawa-san putting accelerometers on the SR3 oplev platforms. We will likely turn the fans off to do measurements. -~
 * ~-We will move the SR2 tilt oplev QPD. -~
 * ~-Real-time model: move the optic set-point to the optic level. -~
 * ~-Update medm screens. -~
 * ~-Shoda-san reported a coil-driver not working properly with the binary input/output. I need to check. -~
 * ~-Test Shoda-san's fisnhing rod off-loading script with SRM sometime next week. -~
 * ~-Terrence will be back on Wednesday. -~

=== Type B ===
==== Report for the week 15-08-2019 (Written by Fabian) ====
 * ~-Shoda-san improved the SR3 optic yaw motion (klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9949|9949]]). -~
  * ~-Improvement in the frequency band from 1 Hz to 2.3 Hz was achieved by modifying the IM-Y filter. The problem was not enough phase margin. -~
  * ~-There's still a peak at 1.3 Hz. -~
  * ~-She also modified the IM SENSALIGN matrix (diagonalization according to resonance peaks?) -~
  * ~-Transfer functions should be measured again. -~
 * ~-The BS optic has a large peak at 150 mHz (klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9991|9991]]). -~

==== Plan for the week 19-08-2019 ====
 * ~-Enomoto-kun requested to extend the oplev control loop down to where the micro-seismic peak is. (Fabian.) -~
 * ~-Assemsment of the motion of the SR optics around the micro-seimic region. (Due today.) -~

=== Type B ===
==== Report for the week 05-08-2019 (Written by Fabian) ====
 * ~-After Shoda-san's report (entry [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9797|9797]]) I checked the condition of the filters in FLOAT state. -~
  * ~-After a few tests I realized the whitening chassis didn't have a whitening filter board. See entry [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9844|9844]]. -~
  * ~-I replaced the chassis with an appropriate one. See entry [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9876|9876]]. -~
 * ~-I checked the configuration of the hardware whitening filters by checking the 32 bit dip switch boards for each supension. See entry [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9823|9823]] and [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9876|9876]]. -~
  * ~-The switch configuration is the same for SRM and SR2. -~
  * ~-For BS and SR3 the configurations are different. -~
  * ~-Additionally, the configuration of the two boards used for the BS oplev are different from each other. -~
  * ~-This situation should be reviewed. -~
  * ~-Type Bp and Type A don't seem to be using software anti-whitening filters for oplevs. I haven't checked their hardwate whitening filters' configuration though. -~
 * ~-At the begining of the week I continued noise hunting in SR3. See entry [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9807|9807]]. The goal was to identify the limiting elements for the control system in ALIGNED state. See entries -~
  * ~-The motion of the '''IP-L''' induces motion in '''TM-P''' and '''TM-L''' in the frequency band '''from 0.135 Hz to 0.4 Hz'''. This should be fixed at the IP. There's no inertial damping yet. -~
  * ~-The motion of the '''IM-L''' induces motion in '''TM-P''' nd '''TM-L''' in the frequency band from '''0.3 Hz to 0.8 Hz'''. Likely, this should be fixed with IML2TMP and IML2TML control filters. -~
  * ~-The motion of the '''IM-P''' induces motion in '''TM-P''' and '''TM-L''' in the frequency band from '''0.135 Hz to 1 Hz'''. The motion in the band from '''0.135 to 0.4 Hz is likely ground motion coming from the IP''', however, the motion from 0.4 Hz to 1 Hz should be fixed with IMP2TML and IMP2TMP control filters. -~
  * ~-The motion in '''IM-Y''' induces motion '''TM-Y''' between '''1 Hz and 2.3 Hz'''. This should be fixed with IMY2TMY control filters. -~
  * ~-I began measuring transfer functions (IM-L to TM-L) but I should finish the setting the software anti-whitening filter first. -~

==== Plan for the week 15-08-2019 ====
 * ~-Finish measuring transfer functions. -~
 * ~-Begin the design of filters. -~

==== Report for the week 7/29 (Written by Fabian) ====
 * ~-I offloaded fishing rods in GAS filters and IPs in BS and SRM. -~
 * ~-I implemented scripts for the automatic measurement of amplitude spectral densities (ASDs) of suspension sensors (usually used for residual motion estimation). -~
 * ~-Highlights of recent ASD measurements can be found in entry [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9726|9726]]. The residual motion was measured in ALIGNED and FLOAT states. -~
  * ~-In SRM and SR3 the motion in ALINED state was smaller than in FLOAT state, which is expected. See entries and respectively . -~
  * ~-In SR2, the motion in '''pitch''' and '''yaw''' displacement is '''larger in ALIGNED state''', and the '''longitudinal velocity''' is the '''same in both states'''. -~
  * ~-In BS, the '''longitudinal displacement''' is the '''same in both states'''. -~
 * ~-Some features of the measured ASDs are the following: * In '''SRM, SR3 and SR2''' in '''pitch''' there is either a large bump (SRM and SR3) or excitation (SR2) between 0.3 Hz and 1 Hz. [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9756|9756]]. -~
  * ~-In '''SRM pitch''' the control system seems to be introducing noise in two frequency bands, before and after the bump. See [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9756|9756]]. -~
  * ~-In '''SR3 pitch''' the control loops seems to be introducing noise between 1 Hz and 2 Hz. See [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9755|9755]]. -~
  * ~-In '''SR2 pitch''' the control loops seems to be introducing noise between 0.380 Hz and 2 Hz. See [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9752|9752]]. -~
  * ~-In '''SR2 yaw''' the control loops seems to be introducing noise between 0.045 Hz and 0.230 Hz. See [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9752|9752]]. -~
  * ~-In '''SR2 longitudinal speed''' the control system seems to excite a large peak at 0.705 Hz. See [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9752|9752]]. -~

==== Plan for the week 8/5 ====
 * ~-Check the BS amplitude spectral densities. -~
 * ~-Check the longitudinal degree of freedom in SRs. -~
 * ~-Aim to identify noise sources. -~

=== Type B ===
==== Report for the week 7/22 (Written by Fabian) ====
 * ~-Shoda-san set the auto-measurement scripts and directories. She measured the transfer functions having the suspensions in FLOAT state. -~
 * ~-SR3 IM H2 OSEM channel noise hunting (klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9613|9613]] and [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9629|9629]]).The symptom was that the noise in SR3 IM H2 channel was 4.7 times larger than in similar channels. When the suspension was quiet H2 was not measuring any displacement but only noise. We did several measurements: -~
  * ~-We removed the cable from the satellite box at the AA filter input and terminated the input: the noise was still there. -~
  * ~-We terminated the ADC from the inside of the AA filter box: the noise was gone, suggesting the problem was the AA filter. -~
  * ~-We replaced the AA filter and repeated the measurement with the input terminated: the noise was still there. -~
  * ~-We disconnected all the cables from the input of the AA filter and terminated the offending channel: the noise was still there. -~
  * ~-We also changed cables and tried connecting the AA filter to the SRM rack but the noise was still there. -~
  * ~-The solution was to use other channels for all IM-H OSEMs. The real-time model was changed accordingly. -~
 * ~-The SR3 LVDT driver broke down (klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9659|9659]]). -~
  * ~-We changed the AA filter power cable and when we turned the filter back on the whole rack turned off momentarily and came back on, with the exception of the LVDT driver. -~
  * ~-We tried turning it on but it kept switching off by itself. Tomura-san suspects there's a grounding problem. -~
  * ~-We decided to change the driver. -~
 * ~-LDVT driver replacement and adjustment (klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9658|9658]] and [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9025|9025]]). -~
  * ~-For each channel there are three resisitors which require adjustment and determine an input gain, an output gain and a phase. -~
  * ~-The phase was originally measured with an oscilloscope and the resistor was adjusted using also the oscilloscope. -~
  * ~-The output gain resistor was set to the desired value using the multi-meter. -~
  * ~-For the input gain we tried mesuring the signal amplitude with the oscilloscope (per Nikhef instructions) but we didn't see any obvios change when changing the resistence value. -~
  * ~-Alternatively we measured the input resistence values in the old cards and set the new ones accordingly. -~
  * ~-We did quick measurements of transfer functions and they looked alright. Measurements with better frequency resolution are needed. -~

==== Plan for the week 7/29 ====
 * ~-Noise assessment in SR3. * IM-Y integrated RMS displacement with control system on. Compare with klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9494|9494]]. -~
  * ~-Terrence verbally reported LVDTs are particulrly noisy. -~
  * ~-I would like to measure ASD for all sensors (in FLOAT state) and compare with other suspensions. -~
  * ~-Miyakawa-san is interested to find the origin of the noise in one particular channel. -~

 * ~-Check SRM BF position. The set point should be zero (klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=8672|8672]]) but today I realized it was set to 100 um sometime. -~
 * ~-Check if we need to offload coil-magnet actuation onto fishing rods. -~
 * ~-Remove the software de-white (OSEMs) and antiWTN (oplevs) filters used in some or all suspensions. We don't have hardware whitening filters at the input. -~
 * ~-Compile information about Guardian states and make it available to all. -~

==== Vacation/Travel Info ====
 * ~-Terrence left Kamioka. He will be back on September. -~

=== Type B (Mark) ===
==== Report for the week 7/15 (Written by Fabian) ====
 * ~-SR3 IM H2 noise hunting. -~
 * ~-SRM oplev condition: when the suspension is in ALIGNED state the oplev (pitch) is saturated and yaw within an inconvenient range (non-linear). See klog entry [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9562|9562]]. -~
  * ~-Currently we don't have a good reference for the optic alignment and we cannot decide by how much we should move the QPD. This situation is not new and we tried to cope with it by using historical data of IM DC feedback signal in a good orientation for the DRMI. However, this strategy didn't work. -~
  * ~-The consequence is that in ALIGNED state the pitch feedback DC signal drifts. -~
  * ~-Kokeyama-san and Valera aligned the mirror, provided a reference and we were able to move the QPD. See entry [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9579|9579]]. -~
  * ~-The big flange was moved to another place. -~
 * ~-BS IM2TM transfer functions were measured in ALIGNED state with the control system on. See entry [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9571|9571]]. -~
 * ~-HPCD modification. See entry [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9541|9541]] and comments. -~

==== Plan for the week 7/22 ====
 * ~-Go back to the tunnel on Monday to continue the investigation in SR3 IM H2 OSEM noise. -~

==== Vacation/Travel Info ====
 * ~-Terrence goes back to Hong Kong on 7/27 (sat), last day in Kamioka: 7/25 (Thurs). -~

=== Type B (Mark) ===
==== Report for the week 7/8 (Written by Fabian) ====
 * ~-There was DAQ channel update on Wednesday. -~
 * ~-After making a wind shield for SR3 oplev last week Terrence revisited the design of the IM to TM control filter with oplev and tried to reduce the residual motion peak at 1.4 Hz reported by Izumi-san. -~
 * ~-Last week we moved all the SRs oplev QPDs because they were off by an unsuitable amount. After the interfrometer was aligned again we realized some QPDs will likely require to be adjusted again (optimal position would be within ±50 in normalized displacement units): SR2 tilt and SRM tilt require further adjustment. -~
 * ~-During DRMI commissioning people realized the SR3 yaw motion was too large and was compromising the stability. * The yaw peak-to-peak motion was 6 µrad and involved IM/RM/TM resonat modes at ~0.147 Hz and ~0.172 Hz. -~
  * ~-Terrence realized the amplitude decreased just by turning off the IM yaw control. He tried to damp IM-Y with the oplev but more time is required. -~
  * ~-We realized the H2 IM OSEM is likely too noisy and excites resonant motion. We went to the mine, checked the LED current monitor but couldn't find anything obviously wrong using the oscilloscope. More investigation is needed. -~
  * ~-Enomoto-kun pointed out that the IM2TM oplev DC control might be marginally stable. Terrence measure the IM-Y to TM-Y transfer function and designed the filter again allowing a suitable phase margin at 0.14 Hz. -~

 * ~-In the satellite boxes the label '''"CURR Mon. for PD"''' should be '''"CURR Mon. for LED"'''. -~
 * ~-SR3 and SRM oplev sled are decreasing their power (e.g. 50% in 150 days in SR3). The situation has been reported to Akutsu-san already. -~
 * ~-Fabian came up with a preliminary plan to search for common mode motion in Type B systems (after talking with Miyo-kun, Terrence and Lucia.) -~
 * ~-Report the status of the control system. -~

==== Plan for the week 15/8 ====
 * ~-Go back to the tunnel on Tuesday to continue the investigation in SR3 IM H2 OSEM noise. -~
 * ~-Measure and provide IM-L to TM-P transfer functions to the commissioning team (Stefan's request this morning). -~

==== Vacation/Travel Info ====
 * ~-Terrence goes back to Hong Kong on 7/27 (sat), last day in Kamioka: 7/25 (Thurs). -~

=== Type B (Mark) ===
==== Report for the week 7/1 (Written by Fabian) ====
 * ~-Fabian and Terrence went through the process of oplev diagonalization for the purposes of knowledge transfer and procedure documentation. * There were small corrections to the procedure. -~
  * ~-Terrence wrote the oplev section of the Type B paper. -~
  * ~-Fabian began writing a rough draft of the procedure. -~

 * ~-With the agreement of the comissioning team we decided to move the position of all of oplev QPDs. When the optics were aligned they were away from linear range. * Although the badly affected channels were only three, we decided to adjust all of them. -~
  * ~-The procedure is described in klog entry [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9411|9411]]. -~
  * ~-In order to keep the aligmment information, we took note of the IM DC control signal necessary to achive the alignment and and off-loaded the actuation onto the TEST channels while the oplev was adjusted with the control system off. -~
  * ~-In the case of SRM the oplev was to the point of saturation and was not rendering a usable feedabck signal when the optic was alledgely in aligned state. In this case we looked for the appropriate amount of feedback in stored data from a time in which the DRMI had been locked. -~

 * ~-On Friday we went to the tunnel in order to put a better wind shield around SR3 oplev optics. The aim is to reduce the noise and then improve the performance of the control system. -~
 * ~-We found large and heavy blank flanges leaning on the large SR3 and SRM frames. Removing them will likely disturb the position of the IPs, which would require readjustig the QPDs again. We would like the flanges to remain there for O3 if possible. Fabian will write a message to the vacuum group with our request. -~

=== Plan for the week 7/8 ===
 * ~-Terrence and Fabian will continue writing the oplev diagonalization procedure. -~
 * ~-Fabian will install the rolled-off the DC control filters. -~

=== Type B (Mark) ===
==== Report for the week 6/24 (Written by Terrence and Fabian) ====
 * ~-Type B watchdog/DACKILL is split for tower and payload. Now, tripping the payload watchdog will only trigger the payload DACKILL while tripping the tower watchdog will trigger both watchdogs and DACKILL. The MEDM screen is updated to accommodate the changes. The screen is also modified so the reset buttons for watchdogs and DACKILL are all available on the same screen. In the middle of this work, a bug is discovered in the ModerateWD.c where setting 0 to the ramp down time would cause the WD to loop in an endless ramp down cycle. -~
 * ~-The Guardian is updated to recognize if the payload is tripped and decide which tripped state it should go to, "TRIPPED" or "PAYLOAD_TRIPPED". So, if both tower and payload controls are on while the payload watchdog tripped, the guardian will jump to the "PAYLOAD_TRIPPED" state and shutdown payload controls only. When the WD and DACKILL are reset, the "TRIPPED" state will dump you out to the safe state where all controls are disengaged, while the "PAYLOAD_TRIPPED" state will dump you out to the "ENGAGING_IM_DAMPING" state where the tower controls are still on. -~
 * ~-VIS monitor is updated. It will monitor the raw sensor input and actuator output and check if they are within the operation range. The indicator will turn orange when it is 50% out of range and will turn red if it is 90% out of range. The indicator for actuators will turn blue if they are not in use. The limits of the operating range can be set in userapps/vis/k1/guardian/VIS_DICT.py. The range for OL_PIT and OL_YAW are default to be [-1,1], the lower limit of the OL_SUMs are default to be 1000 counts while those for the other are default to be [-32768,32768]. -~

 * ~-'''If you know the range of certain sensors and actuators, you are strongly encouraged to tweak the thresholds in the file.''' Otherwise, the function of the monitor will be very limited. -~

 * ~-Fabian checked again the GAS filter control noise: * My previous calculation considered damping filters and those injected too much noise in the observation frequency band. Rolling the filters off with (high order) Butterworth filters rendered the system unstable. -~
  * ~-I then considered DC control filters only and I was able reduce the injectetd noise to acceptable levels while keeping the loop stable. As pointed out by Shoda-san, this was the strategy devised for the Type B prototype. -~

  * ~-This has only been tested in software, not in the actual system. I aim to do implement it next week. -~

  * ~-This strategy will work only if the resonant motion of the system is not excited after disabling the payload and GAS chain damping control. On the 23rd of May Terrence measured the residual motion with the control system (including IP) on and off. There was no subtantial difference between the two. I aim to take more measurements. -~

 * ~-Terrence and Fabian are currently going through the oplev diagonalization procedure and will write down the procedure. -~

 * ~-Hirata-san worked in the design of the baffles for the BS. -~

==== Plan for the week 7/1 ====
 * ~-Terrence and Fabian will continue writing the oplev diagonalization procedure. -~
 * ~-Fabian will install the rolled-off the DC control filters. -~

==== Vacation/Travel Info ====
 * ~-Terrence goes back to Hong Kong on 7/27 (sat), last day in Kamioka: 7/25 (Thurs). -~
 * ~-Mark's final day 6/28. -~

=== Type B (Mark) ===
==== Report for the week 6/17 ====
 * ~-Izum-san pointed out the SR3 oplev control loop was not able to damp resonances at 1.4 Hz and 1.2 Hz (klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9290|9290]]). Terrence checked (klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9299|9299]]): -~
  * ~-He found that the optic TFs were coupled to about 10%. I assume something changed because, as far as I understand (Fabian), the oplev had been succesfully diagonalized before to less than 1% coupling. -~
  * ~-He moved the IP and compared IP LENGTH with OPLEV LENGTH noting the the oplev was reading only 70% of the IP displacement. -~
  * ~-In this conditions he diagonalized the oplev but failed. There was still coupling. -~
  * ~-He introduced a factor to have the OPLEV LENGTH measurement equal to IP LENGTH measurement. -~
  * ~-He successfully diagoinalized the oplev. -~
  * ~-He then proceeded to checked the filter but he was unable to reduce the residual motion. Noise is the suspect. Having appropriate wind shield is recommended. -~
 * ~-Fabian worked in rolling-off the control filters of the GAS filters. * According to klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=8979|8979]] the GAS filter control noise has to decrease by 5 orders of magnitude in order to meet the requirement at 10 Hz. -~
  * ~-A Butterworth filter of order 20 with a cut-off frequency of 5 Hz seems to reduce the noise but renders the system unstable. -~
  * ~-More work is necessary. -~

 * ~-Fabian joined Enomoto-kun's lecture on how to align the X Fabry Perot cavity with green light. -~

==== Plan for the week 6/24 ====
 * ~-Terrence will work on... -~
 * ~-Fabian will continue working in the rolling-off of the filters of the GAS filters control loops. -~

==== Vacation/Travel Info ====
 * ~-Terrence goes back to Hong Kong on 7/27. -~
 * ~-Mark's final day 6/28. -~

=== Type B (Mark) ===
==== Report for the week 6/10 ====
 * ~-Supporting the commisioning team. -~

===== BS =====
 * ~-Type B inertial damping. This means geophone diagonalization, blending filter optimizing, etc. -~
 * ~-Optimization gives an odd looking blending filter that blends at ~120 Hz, but works fine in IP L. [[https://klog.icrr.u-tokyo.ac.jp/osl/?r=9199|9199]] -~
 * ~-During PRMI lock, BS residual motion was too high which misaligned the beam too much from time to time and making the lock unstable. -~
 * ~-To fix this, I improved OL windshield so I can study the residual motion of the BS. Then I copied IP L blending filter to IP T and IP Y and cranked up the IP damping and TM damping gain. This suppressed the residual motion so the requirements are met. After this, the BS was not causing any problem to the lock anymore. [[https://klog.icrr.u-tokyo.ac.jp/osl/?r=9219|9219]][[https://klog.icrr.u-tokyo.ac.jp/osl/?r=9235|9235]] -~

=== Type B (Mark) ===
==== Report for the week 6/3 ====
===== SRM Inertial Damping and Residual Motion Stuff =====
 * ~-See Klog [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9064|9064]] -~
 * ~-SRM IP L and T is blended at ~110 mHz (partially optimized by gradient descent, stopped after 10 iterations, then manually adjusted.) while IP Y is blended at 260 mHz (Lucia's old filter). The stability test was carried over the past weekend with inertial damping and all other stages on. The system seems stable. -~
 * ~-To study to performance of the inertial damping, I improvised an OL windshield for SRM. -~
 * ~-Another round of diagonalization was carried just because we have better sensitivity. -~
 * ~-With IP LVDT damping and other controls on, the residual motion is as follows [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9086|9086]]: -~

~-RMS Displacement:
|| ||Requirement ||Result ||
||L ||0.4 µm ||0.1076 µm ||
||P ||1 µrad ||0.0569 µrad ||
||Y ||1 µrad ||0.0598 µrad ||


-~

~-RMS Velocity:
|| ||Requirement ||Result ||
||L ||0.5 µm ||0.1014 µm/s ||
||P ||/ ||0.2165 µrad/s ||
||Y ||/ ||0.1776 µrad/s ||


-~

 * ~-I measured the residual motion with inertial damping, inertial damping without LVDT DC, normal damping without LVDT DC. Results are pretty similar. -~
 * ~-I modified the optimization algorithm to allow fine learning. The cost plateaued after ~300 iterations and the blending frequency was at 78.6 mHz. I tried implementing this blending filter but the system went unstable. -~

===== SR3 Inertial Damping =====
 * ~-The calibration, diagonalization for IP geophones was done. -~
 * ~-I measured and fit noise floor for LVDTs and geophones. -~
 * ~-I found that the IP geophones have a much higher noise level than those from SRM. (1 order of magnitude higher, see [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9088|9088]]) -~
 * ~-This explains why the optimization result of the blending filter converges much quicker than that of SRM, because the geophone noise level limits the blending frequency to be at ~ 130 mHz. -~
 * ~-However, when the system went unstable when the blending filter was implemented. I should try a higher blending frequency or manually adjusting the blending filter to have a proper shape. -~

=== Type B (Mark) ===
==== Report for the week 5/27 (written by Fabian) ====
 * ~-Shoda-san implemented the moderate watchdog: when tripping the amount of actuation will ramp down to zero smoothly. Klog entry [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9009|9009]]. -~
 * ~-Terrence updated the BS guardian. -~
 * ~-Terrence designed a VIS status monitor. The font might be too small for some people. -~
 * ~-Terrence worked on SRM inertial damping. * There is coherence between the geophones and LVDTs at 0.1 Hz. -~
  * ~-He designed a filter with a blending frequency of 0.110 Hz. -~
  * ~-The system seems stable. -~

 * ~-For SR2 Fabian calculated the sensor noise fed back into the system by the control loop: entry [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=8979|8979]]. -~
  * ~-The GAS filters' contrbution is too high. -~
  * ~-I asked Enzo and he didn't rolled off the filters at higher frequecies. -~
  * ~-Filter modification was assigned to Fabian. -~
 * ~-Fabian and Yokozawa-san measured the settings of the SR3 LVDT driver. Klog entry [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=9025|9025]]. -~
 * ~-In the weekly comissioning meeting Fabian made the commitment of writing a list of the measurements we want to do with the DRMI for Type B characterization.I will write it by next week and send it around for comnents. -~

=== Type B (Mark) ===
==== Report for the week 5/20 (written by Fabian) ====
 * ~-Terrence implemented a filter for the inertial damping. See entry [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=8905|8905]]. -~
 * ~-The highlight of the week is Terrence's measurement of the residual motion of the SR2 optic: as measured by the oplev, it does fulfill the RMS displacement and velocity requirements for lock acquisition and, partially, for the observation mode also. See the report at klog entry [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=8949|8949]]. -~
  * ~-The integrated RMS was calculated from 5 Hz to DC because there are some peaks between 8 Hz and 10 Hz and whose origin still has to be clarified. See the report at entries [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=8918|8918]] and [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=8933|8933]]. -~
  * ~-After Akutsu-san's suggestion Terrence improved the air shield in two rounds, including a cylindrical cover around the viewport. This reduced the noise by about a factor of 10. -~
  * ~-He realized setting up the shield may have slightly changed something in the oplev and carried out another round of diagonalization. -~
  * ~-He realized the H3 coil was not working. We fixed it.A cable was disconnected. -~
  * ~-The optic residual motion in L showed a large peaks close to 0.2 Hz, which is where the micro-seismic may become apparent. The peak was not seen in P or Y. The inertial damping system is likely not working in a suitable way. The blending frequency is 0.190 Hz which may not be low enough. -~
  * ~-At the end measurement of the residual motion reported was carried out with inertial damping only in yaw. -~
 * ~-Fabian, Terrence and Fujii-kun measured the settings of the SR2, BS LVDT drivers and one of SR2's. See klogs [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=8941|8941]] , [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=8951|8951]] and [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=8952|8952]]. -~
 * ~-Fabian worked more on the calculation of the amount of sensor noise injected: * I imported Panwei's OSEM noise measurements and calculated the virtual sensor noise. -~
  * ~-I imported Fujii-kun's measuement of the geophone noise and calculated the virtual sensor noise. -~
  * ~-I imported the blending filter -~
  * ~-I wrote lots of comments in Sekiguchi-kun's Matlab scripts. -~
  * ~-I will write a klog soon with preliminar results. -~

 * ~-Fabian submitted and abstract for the Autumn JPS meeting on September. -~

==== Plan for the week 5/25 ====
 * ~-Terrence will work in the optimization of the inertial damping. -~
 * ~-Fabian will continue with the calculation and prepare a presentation for the conference in Brazil. -~

==== Report for Golden Week ====
 * ~-Mark monitored vent and pumpdown, and worked on vistools.py. -~

==== Report for the week of 5/6 ====
 * ~-Lucia and Terrence got the blending working for the IP LVDTs and geophones. -~
 * ~-Terrence and Mark modified the models and MEDM screens to add a new IP block, IDAMP, for damping using the blended signal with inertial information, and a new DAMPMODE block for ramping smoothly between IDAMP and the old DAMP. -~
 * ~-Mark worked on vistools.py, improving the support for cdsMuxMatrix blocks (e.g., OSEM2EUL) and adding support for cdsRampMuxMatrix blocks (e.g., the newly introduced DAMPMODE). He also created two sets of unit tests, unittest.py and unittest.sh, for the two modes of use (as a Python module in other Python programs, and as a command-line utility in bash). -~

==== Report for week of 5/13 ====
 * ~-Terrence measured Q's for nearly all modes on SR2 from TFs and then did some ring-down tests to get a better estimate of some high-Q modes. -~
 * ~-Terrence and Mark looked at the velocity and angular velocity noise of the SR2 as reported by the LEN and TILT OLs. * The Y signal was fairly clean and the Y RMS angular velocity requirement was met. However the L signal was quite noisy, and was also contaminating the P signal due to the large cross terms in the diagonalization matrix. The RMS L from 5 Hz down with damping on was around 10 µm/s, which is 10 times the requirement. However little of this was due to pendulum resonances - most of the noise was featureless and broadband. In displacement units the noise was flat up to about 1 Hz and then smoothly rolled off to f^-2. The noise in the raw P and Y signals (not yet divided by the sum) was about 10 times the noise in the SUM. -~
  * ~-We tried improving the noise with different whitening settings. Increasing the overall gain, increasing it at the QPD but reducing it at the whitening filter, and switching off the 1-10Hz boost whitening filter (and compensating software filter) had no effect. Blocking the beam reduced the noise by about 2 orders and brought the raw P and Y in line with the SUM, suggesting that the problem was before the QPD. Akutsu-san says the noise spectrum looks like it may be limited by air currents, and we probably need better wind shielding. -~

 * ~-Mark swapped in an improved version of `vistools.py`, debugged a few small issues, and simplified the `TYPEB.py` Guardian. -~
 * ~-Fabian embarked on a project to calculate the residual motion within KAGRA's observation band (beginning at 10 Hz) to make sure The Type B suspension fulfills the requirement, and calculate the speed of the optic to make sure we can acquire the lock. * He modified Takanori's Simulink/Matlab simulation in order to include the length sensing oplev and its control feedback path. -~
  * ~-He imported Enzo's IM/GAS/IP-LVDT filters into the simulation. -~
  * ~-He imported into the simulation the measured LVDT floor noise (sensitivities). -~
  * ~-He calculated the IP-L, IP-T and IP-Y sensitivities. -~

==== Plan for week of 5/20 ====
 * ~-Mark at Mitaka Mon, Tue; US from Wed till 6/11. -~
 * ~-Fabian * Import Panwei's OSEM sensitivity measurements and calculate the sensitivity of the virtual IM sensors. -~
  * ~-Import geophones sensitivities and calculate the sensitivity of the corresponding virtual sensors. -~
  * ~-Import Licia's and Terrence's inertial sensing filters. -~

 * ~-Terrence * Try to reduce the OL noise and get better estimates of the RMS velocity with damping on. -~

==== Vacation/Travel Info ====
 * ~-Terrence's next visit from 4/18 to 7/27. -~
 * ~-Mark's final day 6/28. -~

=== Type-B ===
 * We inspected SRM payload and chamber and we think we can exchange the small mirror after the installation of the mid-size baffle. '''When are we going to change it?'''
 * In SR3, we locked the suspension and First Contact was applied.
 * In the corresponding filter bank, I updated the information of the transfer function of the new geophone.

=== Type-Bp ===
 * In PR3 and PR2, we tested the Traverser limit switches.
 * In PRM, OSEMs H2 and H3 were close to the end of their linear ranges, therefore, we moved them. The payload is not as stable as we would've liked, and was disturbed when we installed the Traverser limit switches. See klog.



=== Type-Bp ===
 * In PR3, we removed the First Contact on Monday ad released the suspension. As expected, by locking it for cleaning, we disturbed the pitch of the mirror. However the misaligment this time was different than others before (see a klog from today).
 * Ikeda-san and Hirata-san did in-air cabling for the Traverser.
 * In PR2 we installed the Traverser limit switches and new cable clamps. A few cables broke in the process but they were fixed. We also did in-vacuum and in-air cabling for the Traverser.
 
=== Type-B ===
 * Beam Splitter: after First Contact work last week, the H2 OSEM readout was close to the end of its usable range.
  * We found a cable from one of the RM coils touching the security structure. We moved it and clamped it in a slightly different position.
  * Then we adjusted the pitch and yaw of the BS using the picomotor and F0 yaw stepper motor respectively.
  * We also inspected that nothing around the BF was touching the security structure. Ushiba-san also made a quick test moving up and down the F0 and checking the output of F1 and BF LVDTs.
  * Finally, we moved H2 and H3 OSEMs to more suitable positions.
  * We measured TFs and corroborated that the system is healthy.

 * In SR2, the geophones stopped working, so we checked. The problem was tracked down to the geophone #2 pins powering the preamplfier. There is a short circuit between pins 4 and 5. Next week we will check the in-vacuum cables and, depending on the result, we may want to change the preamplfier or the whole geophone with its pod.


=== Type-B ===
 * Takahashi-san compared SR2 IP TF measurements with those of SRM, and found some discrepancies. The problem was likely produced by the geophone integrator being off. In SR2 it has to be turned on by hand. I measured the same TFs this week and they are fine.
 * With the aim of understanding Terrece's work, in SR2 I tried to do the inter calibration between geophoes and LVDT. At low frequencies the inter calibration seems be good already, but around 1 Hz, where the resonant frequency of the geophone is, there is a deformation of the TF. I've been looking into this, but I don't have anything relevant to report yet.


=== Type-Bp ===
 * We replaced a broken LVDT in PRM. Namey, the one for the BF Damper horizontal LVDTs:
  * In the old board we measured the resitance values determining two gains, and copied them to the new board.
  * After installing the new board, we adjusted the phases in order to achive maximum ouput.
  * Then, in order to calculate the new LVDT calibration factors, we measured the transfer functions from Y actuation to H1, H2 and H3 outputs, and compared with previous measurements.
  * The DC amplitudes and phases of transfer functions are the same as before.
 * Hirata-san continued working in the design of the traverser limit switches. Differences between the real hardware and the 3D-CAD have made the process difficult, but he's now working on a final version. He has reported his work at the ATC-KAGRA meeting.
 * Takahashi-san found out that the LVDT drivers used in PR3 and PRM are using a reference signal with an amplitude of 12 Vpp.

=== Type-B ===
 * Together with Takahashi-san, we measured the whole set of relevant transfer functions in SR2.
  * We compared with measurements from July 2019 and the differences were not relevant. The behaviour of the suspension seems very stable.
  * We recorded in the klog the DC amplitudes of all transfer functions for the purposes of health check.
 * Today Friday I might have disturbed the the oplev.
  * Later, It was possible to engage ALIGNED state with Guardian properly, so it seems fine. Still, we should measure the mirror stage transfer functions on Monday.
  * The readout of the QPDs was low (a few 100s of counts per segment), so I changed he gain in the QPD boards to high with the on-board switch.
 * In the BS payload, the moved the security structure screws closer to their corresponding bodies. The gaps are around 3 or 4 mm.
 * The BS RM coil cables had some plastic sheets that we should have removed after installation but we forgot. We removed them today.


=== Type-Bp ===
 * Hirata-san is still considering which one of the two methods of holding the traverser limit switches is more suitable. In the method which seems more convenient, the switches assembly would be pushed with 28 kgf (one motor considered) in case the switch malfunctions.
 * We recovered PR3 pitch alignment after the earthquake. We didn't have to move OSEM V1.
 * In PR3 oplev, I measured the distances between the optical components.

=== Type-B ===
Miyo-kun sorted out bugs affecting Type-B automeasurement script. There are still some suggestions to tell him.

=== Type-Bp ===
 * We found out the channel name assigment of the BF LVDTs. There was no information about it. We disconnected in-vacuum cables and checked which channel in the medm screen was affected. Hirata-san wrote the information in a document.
 * We inspected PR2 and PRM traversers to learn their orientations with respect to the suspensions. Hirata-san and others compiled the information in a document.
 * We tested the two ways of holding the traverser limit swtiches. Both methods seem good, although one has the disadvantage that some set screws must be used at the further side of the assembly, and they may be accidentally dropped on the suspension.

=== Type-B ===
For the BS:
 * We inspected visually the BS payload and the BF in order to make sure no part of the suspension was too close to the security structure. It was all clear. Actually, the most of the security structure stop screws were too far away from the suspension. We brought closer a few of them hut others remain too far. We should move them to a more suitable place in the near future.
 * The cable of the F0 fishing rod had a problem that we fixed. Probably, the origin of the problem was a loose screw in a connector.
 * I gave information to Miyo-kun for the transfer function auto-measurement system.

=== Type-Bp ===
In PRM, we tested the prototype of the cable clamps for the uppermost stage. The assembly works well but modifications are necessary:
  * More places for cables are needed. We need at least nine and the prototype has only five.
  * We need to devise a way to keep the cable shield, that is exposed, from touching the clamp base, which is made of aluminium.
Hirata-san and I will talk about these changes next week.

Other: we installed in ASC0 rack the QPD driver for the POP infrared transmitted beam.

=== Type-B and Type-Bp TO DO list ===
 * Agree on the changes needed for the Type-Bp cable prototype.
 * Provide more information to Miyo-kun for the auto-measurement system.

 

=== Type-B ===
 * For the BS suspension, I calculated the decay time produced by the damper ring of the ~50 mHz yaw mode of the whole suspension: it is 31 s. Therefore, it's not necessary to adjust the position of the damper ring.
 * I provided Marc with a Matlab version of the SR2 rigid body model. Back in the day I adjusted the parameters of the model for the calculated transfer functions to match the measured ones. Then I used it to calculate the noise budget that was shown in the Type-B paper.

=== Type-Bp ===
 * Last week, we recieved the cable clamps prototype for the uppermost statge of Type-Bp suspensions. We should test them very soon.
 * Hirata-san designed two ways of mounting the limit switches in the traverser. After email discussion with Takahashi-san, Satou-san and me, it seems we'll make prototypes for both version to try.
 * In PRM, we examined more carefully the condition of H1 channel, whose actuation force seems unusually lower than in other channels. By exchanging cables with other coils, actuating on them sepatrately, and using the oplev TILT_VER channel, '''we realized that the problem is not within the chamber and it's likely in the coil driver'''. The effect of H1 on the mirror is at least 50% less of H1 compared with the effect of other coils.
 * Yokozawa-san reported that, in PRM, the length QPD board broke. '''Does anyone know the current status?'''

=== Type-B and Type-Bp TO DO list ===
 * Test Type-Bp cable clamps prototype. This might be a messy task because some cables are entangled inside the chamber and we need to disentangle them. '''Which suspension should we use?'''
 * Check the cable of the BS F0 fishing rod. There might be something wrong with it.
 * I should provide diaggui templates for Type-B automeasurement. Currently, some from Type-A are in place for that.
 * If possible, we should visually inspect the BS payload more carefully in case it's close to touching the security structure. After moving it in yaw for green laser alignment, Hirata-san only did a cursory check.
 * '''Not for VIS but we were assigned to do it:''' install the driver for the QPD in POP table.

=== Type-B ===
 * BS alignment: Last week on Wednesday, we aligned the BS to reflect the X-arm green laser to reach the Y-End.
  * '''We adjusted the yaw of the suspension with the F0 stepper motor.''' We didn't have much time to check, but Hirata-san did a cursory inspection of the payload and it didn't seem to be touching the security structure. Until now there's no indication there's a problem with the suspension, but we should take a more careful look at it soon. Maybe on a Friday.
  * '''During aligmment the oplev went out of range''' and we recover it on Thursday.
  * From Wednesday to Thursday the suspension drifted and '''we had to repeat the X-arm green laser alignment this week again.'''
 * As we have talked before, '''Terrence detected a very large residual motion of the BS optic''', so we investigated.
  * On Thursday last week we removed the temporary duct-shaped wind shields and covered the chamber with our traditional fabric covers. '''The residual motion dissapear.'''
  * Comparison of "before and after" measurements are shown in the klog, '''including one of the performance of the damper ring, from which I can estimate the decay time of the 50 mHz yaw mode of the chain.'''

=== Type-Bp ===
 * In PRM, the mirror actuator H1 has a gain which is unusually higher than the others, and we don't know the reason.
 * There's a klog from September 2019, in which '''it is suggested the coil driver is not working properly and that it should be replaced.'''
 * I superficially assessed the situation by applying actuation in H1, H2 and H4 separately and comparing the motion measured in the oplev QPDs: '''H1 produced less than half the displacement in yaw than H2 and H4.''' We definitely should investigate more.
 * Hirata-san contined the design of the treverser limit switch holders. He also provided information of the position of the centre of mass of PRM mirror.

=== Type-B and Type-Bp TO DO list ===
 * Replace the PRM mirror coil driver actuator, write the actuation matrix taking into account the position of the CM of the mirror, and estimate the relative imbalance in the actuation channels (e.g. using the Pringle mode). '''It would be good to calibrate the oplev QPDs and diagonalize the oplev before doig this.'''
 * For the BS magnetic damper, using the data I took last week, calculate the decay time and adjust the position of the ring if necessary.
 * Check the cable of the BS F0 fishing rod. There might be something wrong with it.
 * We should carry out regular health checks of the suspensions, during night time, for example. We should agree on the implemetation next week.

=== Type-B ===

 * BS F1 LVDT:
  * After calibration last week, I updated the medm values accordingly, however, the amount of actuation needed to move the keystone to the setpoint was too high (-26,000 counts).
  * In order to solve this, I modified the LVDT calibration offset to yield zero, when the keystone is at the nominal 3D-CAD position. I achived this using the old and new calibration data.
  * The difference between the setpoints is only 324 um, which is negligible in terms of the uncertainties we have when we measure the height of the optic.
  * Ther amount of actuation reduced to around -8,000 counts, and will decrease more when the system goes into vacuum.
 * Terrence reported there is some residual motion in the BS suspension. The oplev measures a 50 mHz yaw osciallation which the damper ring is supposed to damp.
  * I assessed the performance of the damper ring with the F0 keystone at two different heights, and from visual inspection of the time series, it seems to be working.
  * The residual motion is even there with the control system off.
  * Currently, we have the impression it might be an enviromental influence. The chamber is not properly shielded against air currents.
  * We need to repeat some measuremnts when there is no one working in the tunnel, and if this does not produce good results, we would like to close the chamber with the clean clothes rather than with the improvised aluminium duct.

=== Type-B ===
 * Terrence reported the BS oplev was out of range, so we recovered the yaw alignment using the F0 yaw stepper motor. We had to move the length sensing QPD but we took note of the initial and final values in case we want to go back. Terrence measured IM TFs to make sure the payload didn't touch the security structure.
 * We assessed the height of the BS:
  * We set BF and F0 to zero
  * We chose the position of F1 so the optic was at the desired height.
  * The amount of actuation F1 required was about -24,000 counts, which is very large, and the keystone moved around -700 um, which is a very small amount given the tools we're using to measure height.
  * Given that the reproducibility of the measurement is within 700 um or so (e. g. PRM SF), for the sake of having a low actuation, we could choose a setpoint higher than the one we measured this week.
 * We calibrated the BS F1 LVDT using the optical displacement sensor.
  * We used a modified holder that allowed us to adjust an additional DoF.
  * We realized this device only works with specular reflection, so we had to tilt the sensor a lot (per the manual) and put think ballast mass with a more reflective surface.
  * We moved the F1 keystone with coil-magnet actuation only and the range was small. We should use the fishing rod also.
  * We got an straight line, which is very good news.
  * We should calibrate again with a larger displacement range.

=== Type-Bp ===

We fixed a traverser cable in PR3. An in-vacuum connector was failing and Hirata-san had to crimp the pins again.

=== Type-B ===
 * We finished replacing the flip adapters in SRM
 * I compiled the results of the cable health check in one spreadsheet in ordert to compare values that should be similar, and I found two possible problems:
  * In SR2, the resistance of IM-V3 coil was higher than expected by about 3 Ohm: we checked and realized the additional resistance comes from a extension cable, but the cable is healthy.
  * In the BS, the a resistance of the F0 FR stepper motor is higher by several Ohm, we need to check next week.
 * In the BS F1 LVDT, we changed the polrity of the LVDT but we didn't confirmed it worked until this week: positive actuation, which moves the keystone upwards, produces a positive LVDT output.
 * We tried to calibrate the BS F1 LVDT today, but we were not able to align the displacement sensor properly. The holder can only be adjusted in one angular DoF, but we need to be able to adjust in teo angular DoF.

=== Type-Bp ===

I compiled the results of the cable health check and found some potential problems, which we aim to fix next week.
    
 * PR2 BF FR, pins 1-6, P1-7: the resistance is 9.7, which is higher than the values in other BF FRs in PR suspensions (8.8 Ohm maximum).
 * PR3 BF V3, pins 1-6, P4-7: the resistance is 13.7 Ohm, which is slightly higher than 11.6 Ohm measured in other LVDTs (approximately).
 * PR3 Traverser: there are several resistance values that are several Ohm higher than expected:
  * R1, P-2-2: pins 1-2, 1-3, 2-3, 2-6, 3-6, 3-7, 6-7.
  * R2, P4-2: pins 1-6, 2-6, 3-6, 6-7.
 * Hirata-san and Nakagaki-san removed some unused cables that were hanging close to PR2.
 * Hirata-san designed cable clamps to be installed at the upper part Type-Bp suspensions.


=== Type-Bp ===
 * They inspected the PR3 traverser to check whether it had the locking assenmblies or they had been removed.
 * We calibrated PRM SF LVDT. The calibration factor hasn't been written in the medm screen yet.
 * In PR2, we connected the cable for TM-H4. A cable with the same label has beed connected. There are old cables around that flange and they should be removed.

=== Type-B SR3 ===
 * Terrence reported SR3 wasn't healthy, the TF measurements looked bad.
 * We inspected the suspension and found several security structure screws touching the IM or IRM.
 * This suspension was healthy, how did it become unhealthy?
  * As they should be, the screws were likley close to the IM and IRM and began touching the payload when yaw was adjusted with the F0 stepper motor.
  * When we removed the F0 yaw stepper motor we followed a method to keep the same yaw position, but it seems it was not accurate enough.
  * We lost the alignment give by the oplev.
  * The incident angle of the green beam might have changed also.

=== Type-Bp ===
==== PRM ====
 * We fixed a broken connection in IM-H2 OSEM cable. We had to replace the whole connector because the pin was jammed. We used to muiltimeter to check the connections were healthy.
 * In PR suspensions there are many connectors that are just hanging. Failure in connections is problem which is likely going to happen again. There are some ideas on how to install cable clamps but we need time and discussion.

=== Type-B ===
==== BS ====
 * We made a rough test of the optical displacement sensor on the optical table; it seems to be working fine. We plan to calibrate F1 LVDT next week because they won't use the laser.
 * In the F1 LVDT adapter box, we exchanged places of the cables connected to pins 2 and 7 in the connector for the cable that goes to the vacuum chamber (primary coil used as a readout coil). This should fix the polarity. We didn't test the modified circuit because of DGS maintenance.

==== Others ====
 * SR2: we finished changing flip adapters.
 * SRM: we changed flip adapters in two flanges.

=== Type-Bp ===
==== PR2 ====
We glued back the magnets onto the mirror.

 * It was not necessary to remove the mid-size baffle. It was possible to do visual inspection of magnets within coil bodies with an inspection mirror.
 * Because the RM is not designed to be a positioning jig for the mirror, a concern was the relative alignment of the two bodies.
  * The method that we used was to release both bodies and lock them, as much as possible, to the position in which they hung free.
  * Despite the absence of two magnets, this method work, likely because the any imbalance affects the RM and mirror in equal amounts becuase they both hang from the IM.
 * During the course of this work, we security structie locking screws were withdrawn by defined distances, not like before.
 * After the gluing, procedure I measured a few transfer functions of the IM and the sysytem seemed to be healthy. '''However, we should do a more comprenhensive set of measurements.''' I didn't do it becuase IFO alignment has a higher priority.

==== PRM ====
During IFO alignment work, we realized the traverser was far away from its centre. Likely, a similar error as PR2 one was made in PRM on Thursday last week.

 * At the begining it moved, but later it jammed.
 * We realized the problem was that some locking assemblies had not been removed and two of them seemed locked. It seems no other suspension has this locking system.
 * We removed them and the traverser now moved smoothly.
 * During the course of this work, we security structie locking screws were withdrawn by defined distances, not like before.

'''It would be good to buy more sligs so we don't have to go back and forth between clean booths to pick them up, please.'''

=== Type-Bp PR2 ===
 * While adjusting the yaw of the suspension with the traverser, the suspension suddently moved a lot in yaw and in pitch also, and the traverser jammed.
 * Mechanical problems detected by visual inspection:
  * At least two traverser motors reached their mechanical limits.
  * Two magnets from the mirror fell off out of the coil body cavity, which was surprising.
  * A security structure stud fell off from the ring below the BF onto the suspended breadboard. Clearly, the stud had not been fastened correctly.
  * Judging from the position of at least one of the BF damper primary coils, the BF had a lot of tilt.
  * On top of the BF there was a cable that was hooking to one of the picomotor assemblies. We don't remember seeing this before, so it migth have been caused by the suspension moving too much in yaw.
 * Apparently, a human error caused the problem.
  * According to Ikeda-san, the suitable way for us to operate the motors is to override the position of the motor that is stored in the driver.
  * He might have forgotten to do this, with the consequence of the driver using an arbitrary value for the current position, thus moving the motor too much.
  * '''Another concern would be the velocity, but I didn't find information about this in Ikeda-san's klog. I'll ask him. '''
 * The traverser has some switches, but they are not limit switches, they are for defining the origin of the coordinate system used to measure the position of the stepper motors.
 * As described in the klog:
  * We locked the suspension.
  * Unhook the cable.
  * Moved the stepper motors by hand (surprisingly, this was easy to do) until they were centered.
  * Released the suspension.

Scraps of text for incorporation in the VIS Meeting Minutes

KAGRA/Subgroups/VIS/MeetingNAOJ

Type-B

  • We inspected SRM payload and chamber and we think we can exchange the small mirror after the installation of the mid-size baffle. When are we going to change it?

  • In SR3, we locked the suspension and First Contact was applied.
  • In the corresponding filter bank, I updated the information of the transfer function of the new geophone.

Type-Bp

  • In PR3 and PR2, we tested the Traverser limit switches.
  • In PRM, OSEMs H2 and H3 were close to the end of their linear ranges, therefore, we moved them. The payload is not as stable as we would've liked, and was disturbed when we installed the Traverser limit switches. See klog.

Type-Bp

  • In PR3, we removed the First Contact on Monday ad released the suspension. As expected, by locking it for cleaning, we disturbed the pitch of the mirror. However the misaligment this time was different than others before (see a klog from today).
  • Ikeda-san and Hirata-san did in-air cabling for the Traverser.
  • In PR2 we installed the Traverser limit switches and new cable clamps. A few cables broke in the process but they were fixed. We also did in-vacuum and in-air cabling for the Traverser.

Type-B

  • Beam Splitter: after First Contact work last week, the H2 OSEM readout was close to the end of its usable range.
    • We found a cable from one of the RM coils touching the security structure. We moved it and clamped it in a slightly different position.
    • Then we adjusted the pitch and yaw of the BS using the picomotor and F0 yaw stepper motor respectively.
    • We also inspected that nothing around the BF was touching the security structure. Ushiba-san also made a quick test moving up and down the F0 and checking the output of F1 and BF LVDTs.
    • Finally, we moved H2 and H3 OSEMs to more suitable positions.
    • We measured TFs and corroborated that the system is healthy.
  • In SR2, the geophones stopped working, so we checked. The problem was tracked down to the geophone #2 pins powering the preamplfier. There is a short circuit between pins 4 and 5. Next week we will check the in-vacuum cables and, depending on the result, we may want to change the preamplfier or the whole geophone with its pod.

Type-B

  • Takahashi-san compared SR2 IP TF measurements with those of SRM, and found some discrepancies. The problem was likely produced by the geophone integrator being off. In SR2 it has to be turned on by hand. I measured the same TFs this week and they are fine.
  • With the aim of understanding Terrece's work, in SR2 I tried to do the inter calibration between geophoes and LVDT. At low frequencies the inter calibration seems be good already, but around 1 Hz, where the resonant frequency of the geophone is, there is a deformation of the TF. I've been looking into this, but I don't have anything relevant to report yet.

Type-Bp

  • We replaced a broken LVDT in PRM. Namey, the one for the BF Damper horizontal LVDTs:
    • In the old board we measured the resitance values determining two gains, and copied them to the new board.
    • After installing the new board, we adjusted the phases in order to achive maximum ouput.
    • Then, in order to calculate the new LVDT calibration factors, we measured the transfer functions from Y actuation to H1, H2 and H3 outputs, and compared with previous measurements.
    • The DC amplitudes and phases of transfer functions are the same as before.
  • Hirata-san continued working in the design of the traverser limit switches. Differences between the real hardware and the 3D-CAD have made the process difficult, but he's now working on a final version. He has reported his work at the ATC-KAGRA meeting.
  • Takahashi-san found out that the LVDT drivers used in PR3 and PRM are using a reference signal with an amplitude of 12 Vpp.

Type-B

  • Together with Takahashi-san, we measured the whole set of relevant transfer functions in SR2.
    • We compared with measurements from July 2019 and the differences were not relevant. The behaviour of the suspension seems very stable.
    • We recorded in the klog the DC amplitudes of all transfer functions for the purposes of health check.
  • Today Friday I might have disturbed the the oplev.
    • Later, It was possible to engage ALIGNED state with Guardian properly, so it seems fine. Still, we should measure the mirror stage transfer functions on Monday.
    • The readout of the QPDs was low (a few 100s of counts per segment), so I changed he gain in the QPD boards to high with the on-board switch.
  • In the BS payload, the moved the security structure screws closer to their corresponding bodies. The gaps are around 3 or 4 mm.
  • The BS RM coil cables had some plastic sheets that we should have removed after installation but we forgot. We removed them today.

Type-Bp

  • Hirata-san is still considering which one of the two methods of holding the traverser limit switches is more suitable. In the method which seems more convenient, the switches assembly would be pushed with 28 kgf (one motor considered) in case the switch malfunctions.
  • We recovered PR3 pitch alignment after the earthquake. We didn't have to move OSEM V1.
  • In PR3 oplev, I measured the distances between the optical components.

Type-B

Miyo-kun sorted out bugs affecting Type-B automeasurement script. There are still some suggestions to tell him.

Type-Bp

  • We found out the channel name assigment of the BF LVDTs. There was no information about it. We disconnected in-vacuum cables and checked which channel in the medm screen was affected. Hirata-san wrote the information in a document.
  • We inspected PR2 and PRM traversers to learn their orientations with respect to the suspensions. Hirata-san and others compiled the information in a document.
  • We tested the two ways of holding the traverser limit swtiches. Both methods seem good, although one has the disadvantage that some set screws must be used at the further side of the assembly, and they may be accidentally dropped on the suspension.

Type-B

For the BS:

  • We inspected visually the BS payload and the BF in order to make sure no part of the suspension was too close to the security structure. It was all clear. Actually, the most of the security structure stop screws were too far away from the suspension. We brought closer a few of them hut others remain too far. We should move them to a more suitable place in the near future.
  • The cable of the F0 fishing rod had a problem that we fixed. Probably, the origin of the problem was a loose screw in a connector.
  • I gave information to Miyo-kun for the transfer function auto-measurement system.

Type-Bp

In PRM, we tested the prototype of the cable clamps for the uppermost stage. The assembly works well but modifications are necessary:

  • More places for cables are needed. We need at least nine and the prototype has only five.
  • We need to devise a way to keep the cable shield, that is exposed, from touching the clamp base, which is made of aluminium.

Hirata-san and I will talk about these changes next week.

Other: we installed in ASC0 rack the QPD driver for the POP infrared transmitted beam.

Type-B and Type-Bp TO DO list

  • Agree on the changes needed for the Type-Bp cable prototype.
  • Provide more information to Miyo-kun for the auto-measurement system.

Type-B

  • For the BS suspension, I calculated the decay time produced by the damper ring of the ~50 mHz yaw mode of the whole suspension: it is 31 s. Therefore, it's not necessary to adjust the position of the damper ring.
  • I provided Marc with a Matlab version of the SR2 rigid body model. Back in the day I adjusted the parameters of the model for the calculated transfer functions to match the measured ones. Then I used it to calculate the noise budget that was shown in the Type-B paper.

Type-Bp

  • Last week, we recieved the cable clamps prototype for the uppermost statge of Type-Bp suspensions. We should test them very soon.
  • Hirata-san designed two ways of mounting the limit switches in the traverser. After email discussion with Takahashi-san, Satou-san and me, it seems we'll make prototypes for both version to try.
  • In PRM, we examined more carefully the condition of H1 channel, whose actuation force seems unusually lower than in other channels. By exchanging cables with other coils, actuating on them sepatrately, and using the oplev TILT_VER channel, we realized that the problem is not within the chamber and it's likely in the coil driver. The effect of H1 on the mirror is at least 50% less of H1 compared with the effect of other coils.

  • Yokozawa-san reported that, in PRM, the length QPD board broke. Does anyone know the current status?

Type-B and Type-Bp TO DO list

  • Test Type-Bp cable clamps prototype. This might be a messy task because some cables are entangled inside the chamber and we need to disentangle them. Which suspension should we use?

  • Check the cable of the BS F0 fishing rod. There might be something wrong with it.
  • I should provide diaggui templates for Type-B automeasurement. Currently, some from Type-A are in place for that.
  • If possible, we should visually inspect the BS payload more carefully in case it's close to touching the security structure. After moving it in yaw for green laser alignment, Hirata-san only did a cursory check.
  • Not for VIS but we were assigned to do it: install the driver for the QPD in POP table.

Type-B

  • BS alignment: Last week on Wednesday, we aligned the BS to reflect the X-arm green laser to reach the Y-End.
    • We adjusted the yaw of the suspension with the F0 stepper motor. We didn't have much time to check, but Hirata-san did a cursory inspection of the payload and it didn't seem to be touching the security structure. Until now there's no indication there's a problem with the suspension, but we should take a more careful look at it soon. Maybe on a Friday.

    • During aligmment the oplev went out of range and we recover it on Thursday.

    • From Wednesday to Thursday the suspension drifted and we had to repeat the X-arm green laser alignment this week again.

  • As we have talked before, Terrence detected a very large residual motion of the BS optic, so we investigated.

    • On Thursday last week we removed the temporary duct-shaped wind shields and covered the chamber with our traditional fabric covers. The residual motion dissapear.

    • Comparison of "before and after" measurements are shown in the klog, including one of the performance of the damper ring, from which I can estimate the decay time of the 50 mHz yaw mode of the chain.

Type-Bp

  • In PRM, the mirror actuator H1 has a gain which is unusually higher than the others, and we don't know the reason.
  • There's a klog from September 2019, in which it is suggested the coil driver is not working properly and that it should be replaced.

  • I superficially assessed the situation by applying actuation in H1, H2 and H4 separately and comparing the motion measured in the oplev QPDs: H1 produced less than half the displacement in yaw than H2 and H4. We definitely should investigate more.

  • Hirata-san contined the design of the treverser limit switch holders. He also provided information of the position of the centre of mass of PRM mirror.

Type-B and Type-Bp TO DO list

  • Replace the PRM mirror coil driver actuator, write the actuation matrix taking into account the position of the CM of the mirror, and estimate the relative imbalance in the actuation channels (e.g. using the Pringle mode). It would be good to calibrate the oplev QPDs and diagonalize the oplev before doig this.

  • For the BS magnetic damper, using the data I took last week, calculate the decay time and adjust the position of the ring if necessary.
  • Check the cable of the BS F0 fishing rod. There might be something wrong with it.
  • We should carry out regular health checks of the suspensions, during night time, for example. We should agree on the implemetation next week.

Type-B

  • BS F1 LVDT:
    • After calibration last week, I updated the medm values accordingly, however, the amount of actuation needed to move the keystone to the setpoint was too high (-26,000 counts).
    • In order to solve this, I modified the LVDT calibration offset to yield zero, when the keystone is at the nominal 3D-CAD position. I achived this using the old and new calibration data.
    • The difference between the setpoints is only 324 um, which is negligible in terms of the uncertainties we have when we measure the height of the optic.
    • Ther amount of actuation reduced to around -8,000 counts, and will decrease more when the system goes into vacuum.
  • Terrence reported there is some residual motion in the BS suspension. The oplev measures a 50 mHz yaw osciallation which the damper ring is supposed to damp.
    • I assessed the performance of the damper ring with the F0 keystone at two different heights, and from visual inspection of the time series, it seems to be working.
    • The residual motion is even there with the control system off.
    • Currently, we have the impression it might be an enviromental influence. The chamber is not properly shielded against air currents.
    • We need to repeat some measuremnts when there is no one working in the tunnel, and if this does not produce good results, we would like to close the chamber with the clean clothes rather than with the improvised aluminium duct.

Type-B

  • Terrence reported the BS oplev was out of range, so we recovered the yaw alignment using the F0 yaw stepper motor. We had to move the length sensing QPD but we took note of the initial and final values in case we want to go back. Terrence measured IM TFs to make sure the payload didn't touch the security structure.
  • We assessed the height of the BS:
    • We set BF and F0 to zero
    • We chose the position of F1 so the optic was at the desired height.
    • The amount of actuation F1 required was about -24,000 counts, which is very large, and the keystone moved around -700 um, which is a very small amount given the tools we're using to measure height.
    • Given that the reproducibility of the measurement is within 700 um or so (e. g. PRM SF), for the sake of having a low actuation, we could choose a setpoint higher than the one we measured this week.
  • We calibrated the BS F1 LVDT using the optical displacement sensor.
    • We used a modified holder that allowed us to adjust an additional DoF.
    • We realized this device only works with specular reflection, so we had to tilt the sensor a lot (per the manual) and put think ballast mass with a more reflective surface.
    • We moved the F1 keystone with coil-magnet actuation only and the range was small. We should use the fishing rod also.
    • We got an straight line, which is very good news.
    • We should calibrate again with a larger displacement range.

Type-Bp

We fixed a traverser cable in PR3. An in-vacuum connector was failing and Hirata-san had to crimp the pins again.

Type-B

  • We finished replacing the flip adapters in SRM
  • I compiled the results of the cable health check in one spreadsheet in ordert to compare values that should be similar, and I found two possible problems:
    • In SR2, the resistance of IM-V3 coil was higher than expected by about 3 Ohm: we checked and realized the additional resistance comes from a extension cable, but the cable is healthy.
    • In the BS, the a resistance of the F0 FR stepper motor is higher by several Ohm, we need to check next week.
  • In the BS F1 LVDT, we changed the polrity of the LVDT but we didn't confirmed it worked until this week: positive actuation, which moves the keystone upwards, produces a positive LVDT output.
  • We tried to calibrate the BS F1 LVDT today, but we were not able to align the displacement sensor properly. The holder can only be adjusted in one angular DoF, but we need to be able to adjust in teo angular DoF.

Type-Bp

I compiled the results of the cable health check and found some potential problems, which we aim to fix next week.

  • PR2 BF FR, pins 1-6, P1-7: the resistance is 9.7, which is higher than the values in other BF FRs in PR suspensions (8.8 Ohm maximum).
  • PR3 BF V3, pins 1-6, P4-7: the resistance is 13.7 Ohm, which is slightly higher than 11.6 Ohm measured in other LVDTs (approximately).
  • PR3 Traverser: there are several resistance values that are several Ohm higher than expected:
    • R1, P-2-2: pins 1-2, 1-3, 2-3, 2-6, 3-6, 3-7, 6-7.
    • R2, P4-2: pins 1-6, 2-6, 3-6, 6-7.
  • Hirata-san and Nakagaki-san removed some unused cables that were hanging close to PR2.
  • Hirata-san designed cable clamps to be installed at the upper part Type-Bp suspensions.

Type-Bp

  • They inspected the PR3 traverser to check whether it had the locking assenmblies or they had been removed.
  • We calibrated PRM SF LVDT. The calibration factor hasn't been written in the medm screen yet.
  • In PR2, we connected the cable for TM-H4. A cable with the same label has beed connected. There are old cables around that flange and they should be removed.

Type-B SR3

  • Terrence reported SR3 wasn't healthy, the TF measurements looked bad.
  • We inspected the suspension and found several security structure screws touching the IM or IRM.
  • This suspension was healthy, how did it become unhealthy?
    • As they should be, the screws were likley close to the IM and IRM and began touching the payload when yaw was adjusted with the F0 stepper motor.
    • When we removed the F0 yaw stepper motor we followed a method to keep the same yaw position, but it seems it was not accurate enough.
    • We lost the alignment give by the oplev.
    • The incident angle of the green beam might have changed also.

Type-Bp

PRM

  • We fixed a broken connection in IM-H2 OSEM cable. We had to replace the whole connector because the pin was jammed. We used to muiltimeter to check the connections were healthy.
  • In PR suspensions there are many connectors that are just hanging. Failure in connections is problem which is likely going to happen again. There are some ideas on how to install cable clamps but we need time and discussion.

Type-B

BS

  • We made a rough test of the optical displacement sensor on the optical table; it seems to be working fine. We plan to calibrate F1 LVDT next week because they won't use the laser.
  • In the F1 LVDT adapter box, we exchanged places of the cables connected to pins 2 and 7 in the connector for the cable that goes to the vacuum chamber (primary coil used as a readout coil). This should fix the polarity. We didn't test the modified circuit because of DGS maintenance.

Others

  • SR2: we finished changing flip adapters.
  • SRM: we changed flip adapters in two flanges.

Type-Bp

PR2

We glued back the magnets onto the mirror.

  • It was not necessary to remove the mid-size baffle. It was possible to do visual inspection of magnets within coil bodies with an inspection mirror.
  • Because the RM is not designed to be a positioning jig for the mirror, a concern was the relative alignment of the two bodies.
    • The method that we used was to release both bodies and lock them, as much as possible, to the position in which they hung free.
    • Despite the absence of two magnets, this method work, likely because the any imbalance affects the RM and mirror in equal amounts becuase they both hang from the IM.
  • During the course of this work, we security structie locking screws were withdrawn by defined distances, not like before.
  • After the gluing, procedure I measured a few transfer functions of the IM and the sysytem seemed to be healthy. However, we should do a more comprenhensive set of measurements. I didn't do it becuase IFO alignment has a higher priority.

PRM

During IFO alignment work, we realized the traverser was far away from its centre. Likely, a similar error as PR2 one was made in PRM on Thursday last week.

  • At the begining it moved, but later it jammed.
  • We realized the problem was that some locking assemblies had not been removed and two of them seemed locked. It seems no other suspension has this locking system.
  • We removed them and the traverser now moved smoothly.
  • During the course of this work, we security structie locking screws were withdrawn by defined distances, not like before.

It would be good to buy more sligs so we don't have to go back and forth between clean booths to pick them up, please.

Type-Bp PR2

  • While adjusting the yaw of the suspension with the traverser, the suspension suddently moved a lot in yaw and in pitch also, and the traverser jammed.
  • Mechanical problems detected by visual inspection:
    • At least two traverser motors reached their mechanical limits.
    • Two magnets from the mirror fell off out of the coil body cavity, which was surprising.
    • A security structure stud fell off from the ring below the BF onto the suspended breadboard. Clearly, the stud had not been fastened correctly.
    • Judging from the position of at least one of the BF damper primary coils, the BF had a lot of tilt.
    • On top of the BF there was a cable that was hooking to one of the picomotor assemblies. We don't remember seeing this before, so it migth have been caused by the suspension moving too much in yaw.
  • Apparently, a human error caused the problem.
    • According to Ikeda-san, the suitable way for us to operate the motors is to override the position of the motor that is stored in the driver.
    • He might have forgotten to do this, with the consequence of the driver using an arbitrary value for the current position, thus moving the motor too much.
    • Another concern would be the velocity, but I didn't find information about this in Ikeda-san's klog. I'll ask him.

  • The traverser has some switches, but they are not limit switches, they are for defining the origin of the coordinate system used to measure the position of the stepper motors.
  • As described in the klog:
    • We locked the suspension.
    • Unhook the cable.
    • Moved the stepper motors by hand (surprisingly, this was easy to do) until they were centered.
    • Released the suspension.

KAGRA/Subgroups/VIS/TypeB/Minutes (last edited 2022-07-29 13:18:56 by fabian.arellano)