The Schmersal AZR31S1 standtill monitors employs e.m.f standstill monitoring, and it has a direct connection to 3-phase motors. It is also ideal for frequency converter connections with rotary hysteresis of 0 ... 1000 Hz, switching frequency up to 16 kHz, and an engine voltage 0 ... 400 V. No adjustment is needed for a required value during commissioning. Moreover, the unit has 3 safety contacts, and 1 signaling output.