Example based on a three-point controller: temperature control for heating and ventilation based on three values associated with the actuator with mechanically controlled valve such as ventilation valve open, both valves closed and heating valve open.
Discrete controllers which, when a certain control deviation is exceeded, change the suddenly at various stages (DIN 19 225).
Example based on a two-point controller: temperature control via a device whose contact switches the heating off by means of a contactor when a limit value is reached.