The Tstat component provides a basic thermostatic (on/off) control with the Boolean Out property and numeric inputs for controlled variable (Cv), Setpoint (Sp), and differential (Diff).
The Tstat component has the following slot:
- Status: shows the component's status;
- Mode: defines the heating or cooling mode of operation;
- Out: the input value converted to the float;
- Setpoint: the setpoint value (temperature setpoint);
- Controlled Variable: the current input value (measured temperature);
- Differential: the deadband set for the current input value–if the Setpoint value is, for example, 25, the Differential value set to 5 means that for the Controlled Variable slot values from 22.5 to 27.5 no action is taken.
In the heating mode, the output is switched off if the controlled variable is greater than the setpoint.
In the heating mode, the output is switched on if the controlled variable is lesser than the setpoint-differentialValue/2 (!).
The behavior is similar in the cooling mode.
If the idea is to split the differential value across the setpoint, then the differential value/2 should be applied to both edges:
In the cooling, mode the output is switched off if the controlledVariable is greater than the setpoint+differential value/2.
In the cooling mode, the output is switched on if the controlled variable is lesser than the setpoint-differential value/2.