Air flow detection

The SCB_ElectricHeater input "FanBeltIn" shall be connected to an airflow signal from another macro, e.g. the fan differential pressure switch. The user has the option to add an own airflow switch for the electric heater or to disable the function entering a "1" as a default value of the input.
Attention: It is highly recommended to connect an airflow switch to avoid damages.

If an airflow switch is connected, any output stage of this step-controller can switch on only, if the SCB_ElectricHeater has detected airflow. If the airflow input will detect a failure during normal operation at this input, the SCB_ElectricHeater will stop immediately, without considering the blocking off times.

After "FanBeltIn" becomes true, the I-enable delay (which is equal to the adjusted I-time) will be effective, to provide only proportional control at start-up.