The speed monitor of the DU series has been developed for safety-related minimum speed monitoring. It receives the pulses from the connected sensors serving as pulse pick-ups on the inputs and calculates the corresponding frequency. By continuously comparing the input frequency (actual value) and the switch point (preset value), the unit promptly detects underspeed.
The minimum speed is easily set via rotary switches.
In addition to the safety relays, transistor outputs are available for status and error indication.
The monitors are widely used on fans of industrial furnaces or paint shops in the automotive industry.