Solution: (I found out in July 08) It was a "out of range" signal.
The probe is adjusted to the middle of the linear Range (~9V). When now vibrations exceed a certain amount - exmpl. >14.7 V or <3.7V, the BN card detects a not ok Status and flashes the green light. Trip multiplier was active, but this has only to do with the signal treatment.
It was caused by the caracteristic of the rotor, which has high vibration on the slim end during start up with 1st and 2nd critical speed.