Agenda/Minutes of the VIS Meeting on 2019/7/26

2019/7/26 14:00 -

Zoom Meeting

Participants:

Progress report

Type-A

Past week report

Moved the SF/BF prototypes from the warehouse of TAMA to the ATC as the references for new design. Opened the cups and then found that the blades in the oldest prototype were broken.
payload damping work is started in ETMX/ITMX(/ITMY) in parallel, mainly with Okutomi-san, Ushiba-san, Fujii. Now ongoing.
- basically: usual damping filters are at INM-stage. Except for IM-stage, only band-pass damping will be available.
- Oplev is used instead of WFS. see klog 9626

Plan for coming weeks

Type B

Report for the week 7/22

Shoda-san set the auto-measurement scripts and directories. She measured the transfer functions having the suspensions in FLOAT state. (Guardian states information still has to be compiled.)
SR3 IM H2 OSEM channel noise hunting (klog 9613 and 9629).The symptom was that the noise in SR3 IM H2 channel was 4.7 times larger than in similar channels. When the suspension was quiet H2 was not measuring any displacement but only noise. We did several measurements:
- We removed the cable from the satellite box at the AA filter input and terminated the input: the noise was still there.
- We terminated the ADC from the inside of the AA filter box: the noise was gone, suggesting the problem was the AA filter.
- We replaced the AA filter and repeated the measurement with the input terminated: the noise was still there.
- We disconnected all the cables from the input of the AA filter and terminated the offending channel: the noise was still there.
- We also changed cables and tried connecting the AA filter to the SRM rack but the noise was still there.
- The solution was to use other channels for all IM-H OSEMs. The real-time model was changed accordingly.
The SR3 LVDT driver broke down (klog 9659).
- We changed the AA filter power cable and when we turned the filter back on the whole rack turned off momentarily and came back on, with the exception of the LVDT driver.
- We tried turning it on but it kept switching off by itself. Tomura-san suspects there's a grounding problem.
- We decided to change the driver.
LDVT driver replacement and adjustment (klog 9658 and 9025).
- For each channel there are three resisitors which require adjustment and determine an input gain, an output gain and a phase.
- The phase was originally measured with an oscilloscope and the resistor was adjusted using also the oscilloscope.
- The output gain resistor was set to the desired value using the multi-meter.
- For the input gain we tried mesuring the signal amplitude with the oscilloscope (per Nikhef instructions) but we didn't see any obvios change when changing the resistence value.
- Alternatively we measured the input resistence values in the old cards and set the new ones accordingly.
- We did quick measurements of transfer functions and they looked alright. Measurements with better frequency resolution are needed.

Plan for the week 7/29

Noise assessment in SR3.
- IM-Y integrated RMS displacement with control system on. Compare with klog 9494.
- Terrence verbally reported LVDTs are particulrly noisy.
- I would like to measure ASD for all sensors (in FLOAT state) and compare with other suspensions.
- Miyakawa-san is interested to find the origin of the noise in one particular channel.
Check if we need to offload coil-magnet actuation onto fishing rods.
Remove the software de-white (OSEMs) and antiWTN (oplevs) filters used in some or all suspensions. We don't have hardware whitening filters at the input.
Compile information about Guardian states and make it available to all.

Vacation/Travel Info

Terrence left Kamioka. He will be back on September.

Type-Bp

Past week report

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Completing the auto-measurement system for Type-B and -Bp.
Working on updating the suspension models.
Working on making user friendly interface.

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Plan for coming weeks

OMMT & OSTM (Takahashi)

Past week report

The standoffs have been delivered. Inspecting the sharpness of notch.
Designing the bottom spacer and the connector plate.

Plan for coming weeks

VIS electronics

Past week report

Plan for coming weeks

Other site works

Safety

Incidents:

Discussion

Travel Plans

Travel (Week of 7/29):
- Takahashi: (Vacation)
- Sato:
- Hirata:
- Shoda:
- Fujii:
- Tanaka:
Travel (Week of 8/5):
- Takahashi: 6-8
- Sato:
- Hirata:
- Shoda:
- Fujii:
- Tanaka:

Next meeting

On 2019/8/2(Fri)