Setting Rules for the PI Control

Large system increases (e.g., high heating output, steep characteristic curves for valves) are controlled with large proportional ranges.

Slow heating systems (e.g., underfloor heating) are controlled with high-level reset times.

Adjustment via control parameter

If no satisfactory control result is achieved by selecting an appropriate heating or cooling system, you can improve the adaptation via control parameters.

Low proportional range	Large overshoot for setpoint changes (also continuous oscillation under certain circumstances), rapid adjustment to the setpoint.
Large proportional range	No (or little) overshooting, but slow adjustment.
No reset time	Rapid correction of control deviations (ambient conditions), risk of continuous oscillation.
Long reset time	Slow correction of control deviations.

The framework conditions for setting the cycle time

For small values, the switching frequency and the bus load are increased.
For large values, temperature fluctuations are created in the room.
Short cycle time for rapid heating systems (e.g., electric heating).
Long cycle time for slow heating systems (e.g., underfloor warm water heating).

Examples

Warm water radiator heating with motorized valve drives

Properties	Parameter	Settings
Heating only	Controller type	Heating
	Control value output	Continuous PI control
	Adjusting the controller to the heating system	Hot-water heating (5 K / 150 minutes)
	Send control value on change by	4 %
	Cyclically send control value	10 minutes

Cooling ceiling with motorized valve drives

Properties	Parameter	Settings
Cooling only	Controller type	Cooling
	Control value output	Continuous PI control;
	Adjusting the controller to the cooling system	Adjustment via control parameter
	Cooling proportional range	Approx. 30 °C(depending on the application)
	Reset time for cooling	Approx. 240 min. (depending on the application)
	Send control value on change by	4 %
	Cyclically send control value	10 minutes

Switching electric radiator heating

Properties	Parameter	Settings
Heating only	Controller type	Heating
	Control value output	Switching PI control
	Adjusting the controller to the heating system	Electric heating (4 K / 100 min.)
	Send control value on change by	4 %
	Cyclically send control value	10 min.

Air conditioning with 4-duct (2-circuit) air convector system (e.g., switching valve drives)

Properties	Parameter	Settings
Heating or cooling as required, with automatic switching	Controller type	Heating and cooling
	Control value output – heating	E.g. switching PI control
	Adjusting the controller to the heating system	Split unit (4 K / 90 min.)
	Control value output – cooling	E.g. switching PI control
	Adjusting the controller to the cooling system	Electric heating (4 K / 100 min.)
E.g., automatically switch between heating and cooling	Switch between heating and cooling	Automatically via the controller

Temperature limitation using shading facility

Properties	Parameter	Settings
Cooling only	Controller type	Cooling
	Control value output – heating	Switching 2-step control
	Hysteresis	Large (e.g. 10 °C)