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| * Activity report for week of 12/12 * Mark, Fabian and Enzo continued BS Test Hang work: * We shipped BS mirror box parts to Shoda-san and components for a new LVDT cable to Hirata-san. * We posed for pictures of the BS by a team from National Geographic. * We installed the BF fishing rod stepper motor adaptor cable. * We tried to install the BF LVDT cable but first we encountered trouble routing it, and then several wires broke at the D-Sub end. * We laid 6 in-air cables from the tank to the PR2 rank for BF and SF picos, steppers and LVDTs. * We lifted the BF/IRM/IM/RM/BS section to weigh it and check its balance. * It was 195.6 kg, which is 18 kg(!) less than the capacity of the SF. * There was a major imbalance in roll: with all four built-in trim masses moved up the +Y end, it still needed 270 g of extra trim mass to be level. This can probably be made up easily by designing the 18 kg of extra mass appropriately. * Unfortunately when we put the payload, the IM was slightly yawed and ended up on the horizontal EQ stop screws. This let the IM-BF maraging rod go slack, which disturbed the leveling of the IM (because every time it is picked up the maraging rod settles in a different place, giving a different suspension point). * We removed the end panels of the IRM to get access to the IM and rearranged the trim mass on the the IM to get it balance to bubble-level precision. (We still need to do fine pitch adjustment with the OL so that the BS is at the right angle, secure the trim mass properly and replace the IRM panels and OSEMs.) * Miyakawa-san and Yamamoto-san redid the cabling from the computer room to the PR2 rack and expected to finish by lunchtime on Friday. * Hirata-san * Did parts and fastener lists for the SR payload. * Did a 3D model with the SR suspension on the BS assembly frame (to help Mark make adjustments to the frame design). * Did 2D drawings of Fabian's concept for BS EQ stop parts. * Did a 3D model of a wire clamp with replaceable jaw parts (to avoid having to reuse parts with scars from pressure). * Did 2D drawings of a new wire clamps for on top of the BS and SR RMs. * BF issue * The BF has four issues that may or may not be related: * The keystone is sitting at an angle, so the bottom of the keystone just barely clears the magnet yoke without rubbing. * The suspension point for the IM rod is offset. Thus: * The BF does not hang level when the IM is suspended from it, even with all built-in trim masses moved to their limits (an additional 270 g stacked on the +Y side of the cap is required). * The offset of the rod also causes an offset of the IRM and IM, which uses up all the adjustment range of the IRM OSEMs and means the EQ stops screws between the IRM and IM cannot be inserted without rubbing. * The load capacity is slightly less than measured by Hirata-san during tuning at the ATC. * The frequency is rather higher than measured by Hirata-san. * Also, the BF/IRM/IM/RM/BS system is 18.1 kg light (195.6 kg) compared to the load capacity of the SF (213.7 kg). * Diagnosis: * The direction of the tilt lines up exactly with one of the blades (the one in the +X,+Y direction on the assembly frame). * The blade bases are adjusted symmetrically relative to the outer edge of the BF. * Therefore the +X,+Y blade is probably either stronger or weaker than the other two. * However even if this was true at the ATC, something has changed during transit. * Designing asymmetric trim mass would fix the imbalance problem but not the offset problem (IRM and IM would still be displaced; EQ stop screws could still not be used). * Quick summary: this is a major nuisance and is repeatedly costing us time, but we could probably make it work if we absolutely had to. * Options: * Muddle through. * Slow, risky. * Bring the BF back to ATC for a tuneup before proceeding with the test hang. * Could almost certainly fix the frequency problem. * ''Might'' be able to fix the offset and/or tilt problems by swapping in the spare blade. * ''Might'' be able to fix the offset problem by adjusting the blade bases to different distances from the edge. * If successful, makes some subsequent steps simpler and/or safer (less asymmetrical trim mass; IRM/IM stops can be used). * Reduces the chance of discovering a show-stopping problem with the BF later. * Might delay design of 18 kg of trim mass (unless it's very adjustable). * Delays finding any problems in other areas (SF, PI etc). * Would distract Hirata-san from SRx procurement at a crucial time. * Allot time for a tuneup between the test hang and the real hang. * Same chance of success at fixing the immediate problem as above. * Possible worse delay design of 18 kg of trim mass (unless it's very adjustable). * Test hang work is harder and slower. * Greater chance of running into a show-stopping problem related to the BF and having to back up in the test hang. * Advances finding any problems in other areas (SF, PI etc). * Could allow more spare blades to be ordered - better chance of getting a well-matched set. * Probably better for Hirata-san. * ??? |
=== Type B (Mark) === ==== Report for week of 1/29 ==== * Fabian and Kozu-kun tested the FR stepper, and calibrated the keystone height as a function of FR position. * Fabian, Hirata-san and Kozu-kun installed and adjusted the IRM, IM OSEMs and associated cables. * Mark derived the diagonalization matrices for SR, posted them as [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=7663| T1807663]] and entered them in the on-line system. * Mark fixed the GASALL screen, which had some elements hardwired to BS and did not work for SR2. * Mark initialized the watchdog section of the SR2 model (filters, thresholds etc). * Mark re-entered the IM OSEM2EUL offsets and gains, which had been entered by Enzo, but had not been saved and had been lost. * Mark identified and fixed a bug in the SF2 whereby the watchdog trigger was derived from the AND of the error signals from the various stages instead of the OR. Thus all stages would have to overload before the watchdog tripped. All other VIS models were similarly affected, and all affected library parts have been fixed, but the other models need to be rebuilt, which should be done at the earliest opportunity, e.g., early next week after the scheduled power outage on Sun 2/18. * Mark fixed the indicators for the watchdog on the OVERALL screen, which also had bad logic. * Mark tried using Shoda-san's measurement script to do TFs. It ran successfully, but the first data set was no good because of two issues: the excitation was apparently too large (even after a reduction by 20) and the SENSALIGN matrix was not initialized. * Hirata-san negotiated with Kimura-san to get the SRM tank mushroom installed (this will probably happen from Tue on the week of 3/5). ==== Plan for week of 2/19 ==== * Enzo back from Tuesday. * Shoda-san at Mitaka. * Hirata-san at Mitaka Mon+Tue (to receive and wash parts). * All others at Kamioka. * - * Do TFs from IM OSEMs to IM OSEMs, OL pitch/yaw. * Lift BF/... section and check total mass and balance. * Cable and test BF picos. * Add section of SS up to SF ring. * Bring in SF. * Hook BF/... section. * Route cables up to under SF. * Check/adjust total mass of BF/... section. ==== Plan for week of 2/26 ==== * Shoda-san at Mitaka. * - * Add Cu segments to SF cap. * Lift SF/... section and check total mass and balance. ==== To-Do Lists, Schedule ==== * [[../March2018]] ==== Vacation Info ==== * Enzo 1/30-2/19. * Fabian 4/2-4/27 vacation (then gone). |
Scraps of text for incorporation in the VIS Meeting Minutes
KAGRA/Subgroups/VIS/MeetingNAOJ
Type B (Mark)
Report for week of 1/29
- Fabian and Kozu-kun tested the FR stepper, and calibrated the keystone height as a function of FR position.
- Fabian, Hirata-san and Kozu-kun installed and adjusted the IRM, IM OSEMs and associated cables.
Mark derived the diagonalization matrices for SR, posted them as T1807663 and entered them in the on-line system.
- Mark fixed the GASALL screen, which had some elements hardwired to BS and did not work for SR2.
- Mark initialized the watchdog section of the SR2 model (filters, thresholds etc).
- Mark re-entered the IM OSEM2EUL offsets and gains, which had been entered by Enzo, but had not been saved and had been lost.
- Mark identified and fixed a bug in the SF2 whereby the watchdog trigger was derived from the AND of the error signals from the various stages instead of the OR. Thus all stages would have to overload before the watchdog tripped. All other VIS models were similarly affected, and all affected library parts have been fixed, but the other models need to be rebuilt, which should be done at the earliest opportunity, e.g., early next week after the scheduled power outage on Sun 2/18.
- Mark fixed the indicators for the watchdog on the OVERALL screen, which also had bad logic.
- Mark tried using Shoda-san's measurement script to do TFs. It ran successfully, but the first data set was no good because of two issues: the excitation was apparently too large (even after a reduction by 20) and the SENSALIGN matrix was not initialized.
- Hirata-san negotiated with Kimura-san to get the SRM tank mushroom installed (this will probably happen from Tue on the week of 3/5).
Plan for week of 2/19
- Enzo back from Tuesday.
- Shoda-san at Mitaka.
- Hirata-san at Mitaka Mon+Tue (to receive and wash parts).
- All others at Kamioka.
- -
- Do TFs from IM OSEMs to IM OSEMs, OL pitch/yaw.
- Lift BF/... section and check total mass and balance.
- Cable and test BF picos.
- Add section of SS up to SF ring.
- Bring in SF.
- Hook BF/... section.
- Route cables up to under SF.
- Check/adjust total mass of BF/... section.
Plan for week of 2/26
- Shoda-san at Mitaka.
- -
- Add Cu segments to SF cap.
- Lift SF/... section and check total mass and balance.
To-Do Lists, Schedule
Vacation Info
- Enzo 1/30-2/19.
- Fabian 4/2-4/27 vacation (then gone).