Piernicola has investigated an unlock that happened during a previous IPATSIA measurement on Dec 03, at  ~10h06m05 utc. It turns out that the unlock was triggered by DET_MAIN who detected too much power on the B1p_PD2 photodiode according to its log file:

2025-12-03-10h06m04-UTC>WARNING-[SHUTTER_OPEN.run] USERMSG 0: Too much power on B1p PD2! unlock ITF and close fast shutter

Indeed, the power on B1_PD2_DC exceeded the threshold of 0.04 set in the DET_MAIN.ini file as shown on the attached figure.

In order to give a bit more of flexibility for the on-going shift, we have increased the threshold to 0.045 today at 11h03 utc. With such a threshold, the power on B1_PD2 will trigger the unlock at approximatively the same time as the power on B1s.

We agreed that the threshold will be lowered back to 0.04 at the end of the shift.