Motivation

The problem of a long time to reach steady state of some BPC for PRM YAW was pointed out in klog34073. After that, to improve the situation, the gains of ITMY BPC PIT and YAW were updated by Ushiba-san in klog34197 on 6/13.
As a follow-up analysis, I chceked the trend data of recent lock with long lock duration.

Result

Figures 1~4 show the timeseries of several BPC controls. In terms of K1:BPC-YAW_PRM_OUTF_OUTPUT, it reached the equilibrium in 12~28 minutes. It is relatively shorter than previous.

In the previous work (klog34073), it was reported that it took 30 minutes to reach an equilibrium of BPC for ITMX YAW. But, this problem does not appear to be happening now.

On the other hand, I found that K1:BPC-YAW_ETMY_OUTF_OUTPUT and K1:BPC-YAW_ITMY_OUTF_OUTPUT reached the equilibrium in ~40minutes after OBSERVATION state. Figures 5~7 show the examples (same lock as Figure 1~4. T-cursors focus on the ITMY and ETMY).