Agenda/Minutes of the VIS Meeting on 2019/7/12
2019/7/12 13:30 -
Participants:
Progress report
Type-A (Takahashi)
Past week report
Updated the Real-time model & medm for the Type-A payload.
The direct feedback paths from TM OpLev to the upper stages are reimplemented.
- The generic feedback path (OLSERVO, so-called band-path comb paths) updates:
- Driving matrices have been separated for each of local-based and global-based signals.
- Decoupling matrices for the photo-reflective sensors have been prepared.
- The diagonalization of these matrices is not implemented yet. We'll do at the moment of necessity.
- DAQ channel reduction is reflected on the current running models.
We found that the DAQ assignment on the channels TM_OPLEV_TILT_(PIT/YAW)_OUT is accidentally disabled. -> recovered.
- The messy overview screen was rearranged.
- Damping filter implementation on the payload is ongoing. (Okutomi, Yamada)
- We started with measuring mechanical transfer functions and checked the filters which are currently implemented.
- With the great effort of Fujii-kun and many commissioners, the current filters seem working well as far as we investigated (ITMY and ETMY)
- We are going to investigate the left parts to understand the situation.
- Study on the deformation of base plate in the GAS filter with the ATC staff.
Plan for coming weeks
Type-B
Report for the week 7/8
- 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-Bp
Past week report
Plan for coming weeks
OMMT & OSTM (Takahashi)
Past week report
- Asking quotations for the modification parts in the mirror gluing jig and the standoff.
- Preparing for shipping of the suspension.
- The mirror will be ready in October.
Plan for coming weeks
- Test the OSEMs at the site.
- Confirm some dimensions on the present OMMT/OSTM suspensions.
VIS electronics
Past week report
Plan for coming weeks
Other site works
Safety
- Incidents:
Discussion
- VIS talk slots at the August F2F
Travel Plans
- Travel (Week of 7/15):
- Takahashi: 16-19
- Sato:
- Hirata:
- Shoda:
- Fujii:
- Tanaka:
- Terrence:
- Travel (Week of 7/22):
- Takahashi:
- Sato:
- Hirata:
- Shoda:
- Fujii:
- Tanaka:
- Terrence:
Next meeting
On 2019/7/19(Fri)