Since the standstill monitor works without sensors, the machine designer does not have to intervene in the "hardware" of the surrounding construction. The safety module is connected directly to a three-phase three-phase motor and measures the frequency of the induced voltage directly - with rated motor voltages of up to 690V. The safety contacts for releasing an interlocking device close as soon as the motor comes to a standstill.

The SSW 303HV can be used in safety circuits up to Category 4 / Performance Level e according to EN 13849-1 and SIL 3 according to EN IEC 61508 - with all common types of solenoid interlocks from the relevant manufacturers.