For controlling a fan or ventilator with up to 3 levels using relays in step or changeover switching. The device also has a potential-free switching output for controlling accessories such as flaps or valves.
The fan level can be selected directly, increased and decreased, and controlled via the control variables of an external control system. It is also possible to override the fan level using forced control. Furthermore, error monitoring and fan run-on can be parameterized using the ETS application.