This morning I have checked a possible workaround to the increase in B1s power during SR misalignment: https://logbook.virgo-gw.eu/virgo/?r=66910

Figure 1. During the lock acquisition of the OMC a check on B1s power is a critical trigger to close the safety shutters for unlocks during that stage of the lock acquisiton

Figure 2. However once B1 is used for DARM control then the trigger on LSC_DARM and the trigger on B1 DC power are much more sensitive than B1s. So the trigger on B1s becomes un-necessary

I have added two lines in DET_MAIN  (line 486 and 662) to change the weight of what is in the trigger between the case when the shutter is open and closed, and tested that it works:

2025-06-06-05h46m34-UTC>INFO...-AcSumChSet> fast_shutter_trigger - rampTime 1s, nStep 7, nb 6/7:  1 B1_PD1_DC_saturation, 1 B1_PD2_DC_saturation, 1 B1_PD3_DC_saturation, 1 B1p_PD1_DC_saturation, 1 B1p_PD2_DC_saturation, 0 B1s_PD1_DC_saturation, 1 fast_shutter_manual_close,
2025-06-06-05h47m43-UTC>INFO...-AcSumChSet> fast_shutter_trigger - rampTime 1s, nStep 7, nb 7/7:  1 B1_PD1_DC_saturation, 1 B1_PD2_DC_saturation, 1 B1_PD3_DC_saturation, 1 B1p_PD1_DC_saturation, 1 B1p_PD2_DC_saturation, 1 B1s_PD1_DC_saturation, 1 fast_shutter_manual_close,
 

I have commented it back out, as it is the wrong place to do it. We don't want to turn off this trigger as soon as we open the shutter, but only once B1 is used for DARM control. If we need again the work around for the B1s increase when SR TY is misaligned, then these lines should be added in ITF_LOCK, with the reactiviation of the B1s check in DOWN state, and the deactivation of the B1s check for example when we arrive in LN1.