Log on Oct. 9th, 2018 (I apologoze this delayed post..)

Koseki Miyo, Taiki Tanaka, Yoshinori Fujii,

= PR2 =
In order to fix the found problems reported in klog#6445, we adjusted the followings:
-- tilt of the BF-GAS keystone york
-- height of the IM-OSEM bodies (V1/V2/V3)

Actually we found that the BF-keystone was tilted and some of the screws which fixed the BF-GAS york were not tightened up enough. (We had failed in the previous try indeed.)

After there adjustment, we found that some vertical transfer functitons became the ones which was expected. It seemed still the BF-primary-coil holder was rubbing with the secondary-coil holder though.
Figure 1 is the TF from BF-GAS to BF-GAS of PR2 before the adjustment. Figure 2 and 3 show the TF of PR2 after the adjustment, and that of PR3 (healthy one) respectively.
  -> At least, the resoant frequency was where we expected. Also the Q factor was not crazily low this time. this was good news.

== Other notes ==
1. After this work, we found one IM-OSEM cable was disconnected (chopped) at the micro-Dsub port, as shown in 1st photo. This issued OSEM was IM-OSEM-V3 and the disconnected cable was for the actuation signal (which had been connected to 8pin, see the photo). Thus IM-OSEM-V3 is able to measure the motion though, is not available fpr the actuation.
Since we could close the IM-loops (actually it worked in some extence), and could not find time slot to fix this before the pumping down, 
we decided to postpone this fixing work until next time of the vaccum break, i.e., hopefully next December.

2. Due to this adjustment, the BF-GAS calibration plot has changed: the calibration factor is same though, the offset is changed.

3. As reported in klog#6504, BF-LVDT-V3 driver or its cable are now suspicious. This will be investigated more deeply.

4. We found that one feedback filter of BF-GAS (dc+damp), which was used so far, was not able to be closed anymore.. the filter is to be tuned again.

5. we (actually Tanaka-kun found this, thanks!) found that the traverser was at the edge of the renge. it cannot be moved in PR3-direction.see the 2nd to 4th photo.

6. more detailed TF measurement results will be posted soon. Thanks Arai-kun in advance! :)

The photos related to this work are stored in:
https://photos.app.goo.gl/ZRvmcyjmNmaFSmLh9