This morning I was contacted by the operator because the galvo loops of B1p_QD1 were opening in LOCKED_ARMS_BEAT_DRMI_3F and it was not possible to close them back.

As shown on the attached figure, the corrections of the B1p_QD1 galvo are indeed much larger (in the negative direction) than what they were yesterday. So we suspect that the ITF is not in its standard alignment working point. This is also corroborated by the observation that the B1p beam on the B1p camera was quite off-centered (at the bottom of the camera).

Putting the SDB1 bench in fixed setpoints (when ITF was in DOWN),  was enough to recenter the beam on the B1p camera. Then the galvo loops are engaging correctly when reaching LOCKED_ARMS_BEAT_DRMI_1F. But the problem reappears as soons as we reach LOCKED_ARMS_BEAT_DRMI_3F because of the engagement of the SDB1 B5 beam drift control. We disabled by hand the SDB1 B5 beam drift control and then it was possible to close the galvo loops of B1p_QD1 even in LOCKED_ARMS_BEAT_DRMI_3F. It was not possible to lock the ITF at further steps due to the high wind activity.

Since we suspect a wrong alignment of the ITF mirrors, we only made minor changes to the SDB2 QPD centering (B1p M2 V: -200, B5 M1 H: -200, B5 M2 V: -200). This is probably not yet enough to lock the ITF, so the proposed procedure will be to disable the SDB1 B5 drift control when arriving in LOCKED_ARMS_BEAT_DRMI_3F, restore the B1p QD1 galvo loops, and then try to go on with the lock acquisition up to the point the mirrors alignment loops are correcting the alignment. When it should be possible to restore the SDB1 drift control and then the floating setpoints.