Lucia, Yoshinori with help of VIS folks and commissioners and ..,

= Background & Target =
--From ITM-height measurement, we found that the height of the IMs were different, and we decided to compensate the difference by the stepping motors (fishing-rods, FR) on the GAS filters.
-- According to the height measurement, we concluded that ITMX should go down by 5.2mm and ITMY should go up by 6mm.
-- Then after the GAS hight adjustment, the height of the TM will be checked interferometer-wise.

= What we did =
-- We updated the calibration factors since some of the calibration factors looked not-updated (ref: klog#8862). sorry for this.
-- We adjusted the GAS-keystone height with FRs;
  -- We first checked the available range of each keystone height according to the calibration curves, and then did the adjustment work.

  == ITMY, done ==
  -- We selected F2 and F3, and pulled up their keystones by ~5.9mm in total (based on the vertical sensor on the BF-damper, K1:VIS-ITMY_BF_DAMP_V_INMON). (Fig1)
    -- Since the calibration factor of F2-GAS was changed around +1650counts (about 1V, as shown in klog#5494) and it was not compensated in this work, it looked that the BF-damper displacement was inconsistent with the shift of F2-GAS.
    -- The adjusted amout is:

  * (1)+(2)~5.9 mm. 

  == ITMX, NOT yet done ==
  -- We selected F2, F3 and BF, and tried to pull down their keystones by 5.2mm in total, but could pulled down by only ~1.6 mm today. (Fig2)
    -- we failed to actuate F3-FR, hopefully due to the driver. This have to be checked in the tunnel.
    -- BF-GAS-keystone hit the stopprt frame when K1:VIS-ITMX_BF_DAMP_GAS_INMON was equal to -2000 (um).
    -- The adjusted amout is:

  * (3)+(4)~ -1.6 mm. 

  === ITMX, Next ===
  -- check the status of the stepping motor driver and activate F3-FR.
  -- summarize the factors, issues we had so far, and tidy up the information.