Agenda/Minutes of the VIS Meeting on 2020/6/26
2020/6/26 14:00 - 15:40
Participants: Takahashi, Fabian, Miyo, Aso, Sato, Shoda, Lucia, Miyoki, Tanaka, Washimi, Hirata, Ishizaki, Ushiba
Progress report
General
Miyo started to prepare the heater jackets for temperature control of GAS. This project doesn't have a time schedule. We have to discuss. (Github Issue)
- We should decide which suspensions will require the heaters: maybe SRM and SR2 (Fabian should check).
- Policy of temperature control during the time in which VIS work will take place: according to what Fabian understood from Miyoki-san, now that there are enough coolers the aim is to keep it to about 23.5 degrees, but we should ask for confirmation.
Type-A
(Takahashi) Tested the accelerometer with the LVDT prototype (Slide).
Type-B
SR2 decay times:
- There were two modes in IP-L whose behavior I coudln't explain: the UGF is about 90 mHz it was not clear why the mode at 671 mHz was damped and why the decay time of the mode at 406 mHz was longer with the control system on.
IP-L open loop transfer function measurement: method with two parallel paths described in klog entry 14582 and final result in entry 14595.
New measurements of decay times with combinations of notches in IP-L and IP-T filters and in TWR_DAMPED state also. See entry 14597.
- Conclusion:
- At 671 mHz the mode is damped by the payload.
- At 406 mHz when the mode is excited externally, the control system produces positive feedback which moves the IP away from the equilibrium position but the feedback signal is not large enough to make it unstable.
I checked BS and SR3 fishing rod conditions and began thinking what to do: humble slides.
Type-Bp
Type-C
- The plan of the black shield which will install on the IMC Type-C was reviewed on 24th. MCe,MCi and MCo will be fitted with the same type of shields as the IMMT and OMMT.
- No report about IMMT2 modification.
Controls
Type-A modeling : brief report
Electronics
- Started the measurements of LVDT combiner.
Post O3
- Post Obs. tasks are on going. Decay time measurements were carried out again. RT model modification for other Type-Bs is planed in this weekend. Sensor correction for SRs and SR suspension update will be started from July.
- O3c will be canceled.
Task towards O4 (List) was revised.
cf. Post Obs. task (Request), Task for O3c (Plan, Sheet), Schedule towards O4 (Chart).
Safety
Discussion
Travel Plans
Next meeting
- On 2020/7/3(Fri)