This is a controller for electric heating elements. It controls three-phase 400 VAC electric heating elements. Time-proportional control - TRIAC technology - is used to control the heating element. A PT500 temperature probe can be connected to measure the ambient temperature. The temperature setpoint can be adjusted via the integrated potentiometer. An optional external potentiometer can be connected to adjust the setpoint remotely. There is one digital input for remote ON-OFF switching and one digital input to switch between a day and night temperature setpoint. The maximum current (resistive loads) is 22 A.