Agenda/Minutes on 2020/11/6

CRY+VIS Interface Meeting

13:30-14:00

Participants: Takahashi, Hagiwara, Miyo, Hirata, Ikeda, Yano, Sato, Aso, Ushiba, Matteo, Sugiyama, Kimura

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.).

14:00-15:00

Participants: Takahashi, Sato, Miyo, Hirata, Ikeda, Yano, Suguyama, Aso, Tanaka, Washimi, Terrence, Fabian

[Miyo] I asked Nakagaki-san who is a new engineer in ICRR to investigate the cabling for all VIS rack. diagram

He found wrong cabling in the LVDT driver for BF damper in PRM. Detail is written in Type-Bp section.

[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.

Cryo-payload was disconnected on 11/3 and the wire was taken down under the cross tube on 11/5 in Y-end.
Started the disassembly of Type-A tower in Y-end. The F1 was dismounted. (Mon., Tue, Wed., Thu., Fri.)

[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.

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)

Circuit boards and electronics parts have been ordered. Some parts provider should be changed.

The week from 11/9

The week from 11/16

KAGRA/Subgroups/VIS/VISMinutes20201106 (last edited 2020-11-06 15:25:50 by RyutaroTakahashi)