Agenda/Minutes on 2020/11/6

Zoom Meeting

CRY+VIS Interface Meeting

13:30-

Participants:

• Post O3 Upgrade portal

• Cryo-payload was disconnected on 11/3 and the wire was taken down under the cross tube on 11/5 in Y-end.
• The L-parts and tie-rods in IYV were replaced. The effects will be checked on 11/20.
• Schedule: Wire disconnection (IX 11/13, EX 11/19), WAB safe mode (10/26-11/13).
• Jig for the FC painting.
• PF actuator: Measurement of coefficients and calculation of the noise (by mid Dec.).

VIS Meeting

14:00-

Participants:

Progress report

General

About LVDT cards

[Fabian and Washim-san]

With the new information that Alessadro (Nikhef) provided a few weeks ago, we began measuring the settings in PR suspensions.

• I realized that the some of the information given to us (JGW-T1604798, Feb 2016) about how to set up the card ready for calibration was wrong.

• Namely, in order to set the phase, it is instructed to use the wrong probe points.

• I wrote Alessandro for confirmation and he provided the correct information.
• The consequences for the already calibrated LVDTs are not necessarly so important:
  • As far as I remember, the people adjusted the phase by maximizing the output, not by measuring the phase directly.
  • Still, from the recent measurements, I can see that some phases are very different from zero, which means we are not having the best SNR we can get from the LVDTs.
• The consequences for LVDT card recovery are more important because, in case a card needs to be replaced, we have to get the same settings in order to preserve the calibration factor.
• In case a card, whose settings have not been measured, breaks, we should:
  • Measure the value of two gain resistors from the top of the card and

  • Measure the value of one resistor from the bottom of the card. This requires removing the card from the chassis.

Type-A

• Started the disassembly of Type-A tower in Y-end. The F1 was dismounted.

Type-B

[Fabian and Washimi-san]

• I got the reviewer's comment on the Type-B paper. It's a long list but many of them are relatively simple. A few of them are a little more challenging.
• We began setting up the clean booth ready for work. We also had had a chat about safety and how to keep the cleanliness.
• We removed most of the screws from the top of BS and SRM chamber and from the +X side door of SRM chamber.
• Akutsu-san and Nakamura-san inspected the BS oplev area with the intention of designing the box.
• Mirapro covered the BS/PR2 area with SUS sheets.

Type-Bp

• We measured the settings of PR2, PR3 and PRM GAS Filters LVDT cards: two resistances and a phase for each channel.
• We'll check the remaining LVDT card in PRM once the cable problem is solved.
• About: the LVDT driver box for PR2 GAS filters:
  • It has a problem with the input power voltage, but it may be just an LED issue because the meaured voltage seems alright. Shimode-san will check on Tuesday.
  • However, I didn't get a return signal from the BF-V LVDTs back into the board. The board might have broken. After Shimode-san finishes checking the power issue I'll investigate more.

• [Miyo] Only the PRM was cabled differently than the other Type-Bp suspensions for the LVDT drivers for BF-damper. klog#15404

  • The D-sub cable for the secondary coil and the cable for the primary coil were swapped.

  • This wrong cabling may be happen in October 2018 when we replace the driver due to malfunction according to klog#6499

  • As far as I know, glitch was occurred after this replacement and this problem have not been solved yet from last year. (klog#9577)

Type-C

Controls

Electronics

Towards O4

• DGS update are on going.
• Schedule.

  • Arrangement of personnel in Nov. (table)

  • VIS

• Procedure documents.

  • Type-A tower installation

  • Limit switches <-- Revised. Small changes in assembly (add one more nut)

  • Limit switch connecting guide

  • Replacement of TF blades

  • Wire gluing in PR3

  • Type-B remedying work

• Criteria in the acceptance test.

Safety

Discussion

Travel Plans

The week from 11/9

• Takahashi: 11/9-13
• Sato: 11/9-12
• Hirata: 11/9-13

The week from 11/16

• Takahashi: 11/16-20
• Sato: 11/16-20
• Hirata: 11/16-20

Next meeting

• On 2020/11/13(Fri)