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Size: 3540
Comment:
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Size: 3633
Comment:
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| Deletions are marked like this. | Additions are marked like this. |
| Line 7: | Line 7: |
| At Kamioka (Mark, Fabian, Enzo, Perry, Hirata-san): | At Kamioka (Mark, Fabian, Enzo, Hirata-san): |
| Line 9: | Line 9: |
| * We cleared space for the PR2 team to remove a bellows from their tank. * We installed safety bars on the pillars near the assembly frame at about waist height for someone on the tall ladder. We reinforced the clamps with cable ties. * We bridged a gap in the second floor on the -X side of the SF2 tank with spare floor panels. * We removed the PI from the assembly frame. * We encountered a problem with the PI-SF rod jamming in the SF. We finally got it out by clamping a pair of vice grips to the rod and hammering. We found that the receptacle part was the right size (7.0 mm) but had been deformed around the edge. Hirata-san used a knife and sandpaper to lean up the edge and then ultrasonically cleaned it. * We removed the LLB blade units from the PI, removed the blades from the clamps and sent the blades away for more rework to fix the length problem. Fortunately the tab section at the tip is fairly long, so we can just add a second hole further from the end. * We tested the SR fishing rod again, but it would only go up, not down. We found that reseting the driver fixed it, but we also moved the driver boxes into the cleanbooth to reduce the length of the motor cables. (To support the drivers, we had to run some long DC and LAN cables.) * We adjusted the limit nut on the SF fishing rod to increase the range. * We debugged an issue with the SF keystone sitting lower than previously and found we had accidentally left two eyebolts on top of the BF. We retrimmed the BF/... section to reset the keystone to nominal (65.5 mm) with the fishing rod at mid-range. * We removed one segment of the Cu ring on the SF cap and reconfigured the other two to be symmetrical. * Fabian designed a layout for the SF damper ring magnets that would work with the modified Cu ring, and placed the magnets with the template. The poles of the magnets were not on the expected faces so we had to stand the magnets up, with the 12x12 faces sideways and the 10x12 mm pole faces up/down. We will need to raise the magnet ring by 2 mm to allow for the extra height. * Hirata-san made an adapter cable for the PI vertical LVDT to let it connect to a standard Type 1 cable. * Enzo made a PI yaw/vertical stepper adapter cable and a trial geophone descrambler cable (one of three). * We placed the geophones on the PI but discovered we didn't have some mounting brackets called out in the 3D CAD. * Fabian added the remaining cable clamps to the PI. * We found that part of the problem with the SF LVDT was that the actuation had not been enabled for SF or F0 in the real-time model. We fixed the model and are now able to drive the LVDT actuator and see input at the LVDT sensor. However there is apparently a lot of coupling directly from output to input (presumably from transformer action between the sensing and actuation coils), so we're investigating. |
* Inspected LLB in tank - in a good position, but not very clean - apparent water spots and dirt. * Found the geophone adapter plates. * Retested SF FR stepper - still good. * Finally got SF LVDT working: * Found a short in the primary coil due to Al foil used for mechanical reinforcement at vacuum feedthrough connection. * Did a full calibration and found that linear range was too small (0.75 mm!) and did not cover nominal keystone height. * Decreased gain to increase linear range. * Adjusted the height of the yoke and secondary coil unit to center the linear region around the nominal keystone height. * Implemented velocity damping. * Found all parts for the LBB and damper rings. * Cu segments and some other parts were very dirty - wiped carefully for now, but should be properly cleaned before final install. * Outrigger parts for LBB have M16 thread cut directly into Al but should have had M16 helicoils. This is a galling risk with Ag-coated rod receptacles. Hirata-san organized rework. * Some special lock nuts are in short supply and are being borrowed from supply at ATC for next batch of BFs. * Made remaining two geophone in-air descrambler cables (total three). * Installed a thermometer supplied by Kokeyama-san on the tower around the BS tank. * Prepared the SF damper. * Designed a pattern of magnets for the two-segment arrangement of SF damper and laid it out on the magnet ring with the template. * Moved the Cu segments on SF cap by 30° (the cap had not been in the right position earlier). * Reinstalled PI: * Raised the PI with the crane and hooked the SF damper ring. Some of the rods did not fit the receptacles due to tolerance issue, but by going through a large number of rods and receptacles, we found three working sets. * Craned the PI onto the frame and suspended the SF/... section, this time with the hex cable clamp on the F0-SF rod. * Tensioned the PI yaw return spring, installed (but did not cable) the yaw stepper and adjusted the yaw of the SF/... section. We worry the return spring is not stiff enough. * Installed (but did not cable) the geophones. * Recentered the IP. The extra weight from the geophones (≈42 kg) and SF damper ring (≈17 kg) had brought the IP to near the point of instability, so we removed one arc weight (≈17 kg) and rearranged the other two in the top row to be symmetrical. * Added ballast to set the height of the F0 keystone. We now have about 6 kg in hand (due to removing one of the Cu segments for the SF damper). This should be enough margin for cables, temperature fluctuations etc. |
| Line 29: | Line 38: |
| Weeks of 5/22, 5/29: * Retest SF stepper every day, to see if problems recur. * Find/install geophone adapter plates or improvise replacement. * Reinstall PI, this time with rods and damper ring. * Reinstall PI-SF rod, this time with hex cable clamp. * Cable/test PI geophones LVDTs and steppers. * Reinstall LBB blade units. |
Week of 5/29, 6/6: * Cabling: * Route BF/... cabling up past SF to PI. * Route SF cabling up to PI. * Add Type 3 extensions to SF/... cables. * Move vacuum flanges to positions on assembly frame more convenient for next stage (accessible from second floor, one on each corner of frame). * Move in-air cabling to match flange positions. * Cable and test PI vertical LVDT. * Calibrate PI vertical LVDT. * Set yoke on PI vertical LVDT (if necessary). * Cable and test PI yaw stepper. * Cable and test PI vertical stepper. * Cable and test PI horizontal steppers. * Cable and test PI horizontal LVDTs. * Calibrate PI horizontal LVDTs. * Crane into tank. |
Scraps of text for incorporation in the VIS Meeting Minutes
KAGRA/Subgroups/VIS/MeetingNAOJ
Type B (Mark)
Past week report
At Kamioka (Mark, Fabian, Enzo, Hirata-san):
- Inspected LLB in tank - in a good position, but not very clean - apparent water spots and dirt.
- Found the geophone adapter plates.
- Retested SF FR stepper - still good.
- Finally got SF LVDT working:
- Found a short in the primary coil due to Al foil used for mechanical reinforcement at vacuum feedthrough connection.
- Did a full calibration and found that linear range was too small (0.75 mm!) and did not cover nominal keystone height.
- Decreased gain to increase linear range.
- Adjusted the height of the yoke and secondary coil unit to center the linear region around the nominal keystone height.
- Implemented velocity damping.
- Found all parts for the LBB and damper rings.
- Cu segments and some other parts were very dirty - wiped carefully for now, but should be properly cleaned before final install.
- Outrigger parts for LBB have M16 thread cut directly into Al but should have had M16 helicoils. This is a galling risk with Ag-coated rod receptacles. Hirata-san organized rework.
- Some special lock nuts are in short supply and are being borrowed from supply at ATC for next batch of BFs.
- Made remaining two geophone in-air descrambler cables (total three).
- Installed a thermometer supplied by Kokeyama-san on the tower around the BS tank.
- Prepared the SF damper.
- Designed a pattern of magnets for the two-segment arrangement of SF damper and laid it out on the magnet ring with the template.
- Moved the Cu segments on SF cap by 30° (the cap had not been in the right position earlier).
- Reinstalled PI:
- Raised the PI with the crane and hooked the SF damper ring. Some of the rods did not fit the receptacles due to tolerance issue, but by going through a large number of rods and receptacles, we found three working sets.
- Craned the PI onto the frame and suspended the SF/... section, this time with the hex cable clamp on the F0-SF rod.
- Tensioned the PI yaw return spring, installed (but did not cable) the yaw stepper and adjusted the yaw of the SF/... section. We worry the return spring is not stiff enough.
- Installed (but did not cable) the geophones.
- Recentered the IP. The extra weight from the geophones (≈42 kg) and SF damper ring (≈17 kg) had brought the IP to near the point of instability, so we removed one arc weight (≈17 kg) and rearranged the other two in the top row to be symmetrical.
- Added ballast to set the height of the F0 keystone. We now have about 6 kg in hand (due to removing one of the Cu segments for the SF damper). This should be enough margin for cables, temperature fluctuations etc.
Plan for coming weeks
For more detail, see KAGRA/Subgroups/VIS/TypeB/ToDo.
Week of 5/29, 6/6:
- Cabling:
- Route BF/... cabling up past SF to PI.
- Route SF cabling up to PI.
- Add Type 3 extensions to SF/... cables.
- Move vacuum flanges to positions on assembly frame more convenient for next stage (accessible from second floor, one on each corner of frame).
- Move in-air cabling to match flange positions.
- Cable and test PI vertical LVDT.
- Calibrate PI vertical LVDT.
- Set yoke on PI vertical LVDT (if necessary).
- Cable and test PI yaw stepper.
- Cable and test PI vertical stepper.
- Cable and test PI horizontal steppers.
- Cable and test PI horizontal LVDTs.
- Calibrate PI horizontal LVDTs.
- Crane into tank.