[Takahashi, Hirata, Dan, Washimi, Ikeda, Aso]
We continued the adjustment of the suspension opening the top belljar.
- The height of the BF keystone was almost at the lower limit. We lifted the keystone with the FR by ~30000 steps. We adjusted the horizontal OSEM position on the IRM so that the flaps could keep a clearance. The height of the BF keystone was set to ~1800 (the setpoint was 1280). The behavior of BF GAS became natural.
- We attached all magnets to the yoke on the BF. We released the TM, RM, IM, IRM, and BF.
- When we released the SF keystone, we found the BF V2 coils were very close to each other. We adjusted the position of the secondary coil. The V2 signal was changed from 6400 to 600 in um.
- We tried to set the height of the SF keystone to -500 (the setpoint was 0). Though the SF keystone was close to the upper limit, the LVDT signal showed -1900 um. Though we tried to lift the keystone with the FR, the signal had no response. When we touched the Dsub connector for the SF LVDT, the signal jumped to 2000 um.
- The cable connection at the connector was unstable. We fixed the connector on the SF bottom plate with peek ties.
- We removed four ballast masses (φ40 x 3t) from the BF. The SF LVDT signal changed from 2000 to 1300 while the BF V1~3 signals changed from 4700 to 60, 6400 to 50, and 3900 to 60 respectively. The amount of changed signal between the SF LVDT and the BF V1~3 were inconsistent.
- We calibrated the SF LVDT compared with the BF V (plot). The coefficient was about 0.2um/count.
