This invention relates to a safety system for an electrically driven medical delivery device for delivering a dose of medication, wherein the safety system is configured for preventing delivery of an erroneous dose of the medicament and comprising detector means for registering mechanical movement, the system comprising at least two detector means (10, 11) for detecting a mechanical parameter and for emitting signals to control circuits (14, 15) configured for controlling the rower supply to driving means (12) for the delivery device. Further, this invention relates to a computer-readable medium comprising a program for controlling a delivery device etc. This allows providing a system that works very quickly, accurately and reliable as to preventing an erroneous dose of medication.