I remeasured the error signal for the third time.

This time I adjusted IY and EY set points to match TMSY QPD position on 12th before the measurement
and also measured TRANS power.
My brief consideration is as follows.

• According to result of TRANS power, TRANS power is max on about 0 point of error singal.
  (If the maximum amount of transmitted light occurs at a position outside of the reference 0, it is possible that the process of aligning in the first ADS is not aligning enough globally.)
• In the case of linear match of the three times results, the offset changes.
• If it is not a linear error signal, it varies from day to day; It's hard to get reproducibility.
  （The sensitivity of the WFS may be poor??）

This consideration needs more thought.
I took pictures of the beam spot position with T-cam and will summarize them later.