= Agenda/Minutes of the VIS Meeting on 2019/8/2 =
2019/8/2 14:00 -

[[https://zoom.us/j/203743987|Zoom Meeting]]

Participants:

== Progress report ==
=== Type-A ===
==== Past week report ====
* Input from YF:
 * ITMY repairing work: see the klog#9732, #9765 and their thread.
   * The stepper motor was calibrated. The coefficients should be available for other suspensions.
   * Main concern (for me) is if the BF-Yaw TF is as designed or not. I will do a measurement for this kind of stuffs tomorrow early morning.
 * Thanks to Kokeyama-san, the Type-A common guardian was created.
  * klog#9762 says that:
    * For ETMY it was confirmed that the guardian worked properly.
    * For ITMX/ETMX, the new guardian was installed but they are to be tested.
    * For ITMY, still old one is running.
  * About payload damping:
    * For ETMX, ETMY, the servo system suppress the angular fluctuation to about 0.1urad in RMS when there is no RM-chain mode is excited. Some of the damping loops are to be created (for ETMX), for like 2.5Hz mode in L etc.
    * It was also found that some of the ETMX/ITMX filters became unstable just after external disturbance like earthquakes. Actually the oplev signal became saturated.
      * Then I found that the photo-sensors (PSs) damped the dominant mode when the large oscillation (for the oplevs) was excited, even with the PSs of ETMX[1]. This was tested in only MN-L though. 
      * PS-damping state should be added to the guardian, just for a case where a large oscillation is excited.
      * Using the oplev-loops after the system calmed down will improve this issue.

 * About IP and BF controls,
  * I have started a preparation for a feed-forwarding test which uses seismometer signals for IP- or BF-LVDTs. This is just for a local control.
  * If you change the configuration of the IP or BF control filters, please report in klog.



[1] The PSs of ETMX has the most terrible noise level. (I will post a log for this.)

==== Plan for coming weeks ====
 * clarify the task assignments for Type-A team again. (To be honest, *I* would like to be away from the VIS duty a bit more..)

=== Type B ===
==== Report for the week 7/29 ====
 * 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-Bp ===
==== Past week report ====
==== Plan for coming weeks ====
=== OMMT & OSTM ===
==== Past week report ====
==== Plan for coming weeks ====
=== VIS electronics ===
==== Past week report ====
==== Plan for coming weeks ====
=== Other site works ===
=== Safety ===
 * Incidents:

== Discussion ==
== Travel Plans ==
 * Travel (Week of 8/5):
  * Takahashi:
  * Sato:
  * Hirata:
  * Shoda:
  * Fujii:
  * Tanaka:

 * Travel (Week of 8/12):
  * Takahashi:
  * Sato:
  * Hirata:
  * Shoda:
  * Fujii:
  * Tanaka:

== Next meeting ==
On 2019/8/9(Fri)