SetPointSlide

SetPointSlide (FB)

FUNCTION_BLOCK SetPointSlide

Short description

Generation of a setpoint temperature depending on the outside temperature Principle: Linear shift Typical application: Adjustment of a room setpoint temperature in summer operation (energy saving)

Representation

Interfaces

Inputs

Name	Data type	Value range	Initial value	Function
rOutTemp	REAL		0	Current outside temperature

Outputs

Name	Data type	Value range	Initial value	Function
rSetPoint	REAL			Current setpoint temperature
bOverThrust	BOOL			Indicator - shift (FALSE = not active, TRUE = active)

Setpoints / parameters

Name	Data type	Value range	Initial value	Function
rDeadZone	REAL		2	Dead zone between on- and off-point for the output bOverThrust at the beginning of the shift
rMaxW	REAL		25.0	Maximum absolute setpoint temperature
rW2	REAL		25.0	Setpoint temperature at outside-temperature point 2
rTo2	REAL		40.0	Outside temperature at outside-temperature point 2
rW1	REAL		20.0	Setpoint temperature at outside-temperature point 1
rTo1	REAL		30.0	Outside temperature at outside-temperature point 1
rManValue	REAL		0.0	Manual override: manual value
eManModeN	eMANNUM	eMANNUM.Auto, eMANNUM.Man		Manual override: operating mode

Function description

General

This function block is used to generate a setpoint temperature rSetPoint depending on the current outside temperature rOutTemp. The mapping is created by a linear function defined by two points (outside-temperature point 2: rTo2 and rW2, outside-temperature point 1: rTo1 and rW1) The setpoint temperature is limited upwards by the absolute maximum value rSetPoint is limited upwards by the absolute maximum value rMaxW is limited downwards by the setpoint temperature at outside-temperature point 1 rSetPoint is limited downwards by the setpoint temperature at outside-temperature point 1 rW1 is limited downwards by the setpoint temperature at outside-temperature point 1 rSetPoint can be fixed to the constant value by the operating mode eManModeN (eManModeN = eMANNUM.Man) to the fixed value rManValue is fixed. On every switch of the operating mode to manual operation (eManModeN = eMANNUM.Man) the manual value rManValue is replaced by the current setpoint temperature rSetPoint . If the outside temperature at outside-temperature point 1 approaches rTo1 the outside temperature at outside-temperature point 2 rTo2 to less than 0.5°C, the outside-temperature point 1 rTo1 is automatically corrected to a difference of 0.5°C (to avoid too steep characteristic curves). The outside-temperature point 1 rTo1 is therefore always numerically smaller than outside-temperature point 2 rTo2. A temperature difference of 6°C between the outside temperature and the setpoint temperature is most commonly used.

Indicator - shift bOverThrust

Condition	bOverThrust	Notes
rOutTemp > rTo1	TRUE	Setpoint shift is active
rOutTemp < (rTo1 - rDeadZone)	FALSE	Setpoint shift is not active

CODESYS

InOut:

Scope	Name	Type	Initial
Input	rOutTemp	REAL	0
Input Const	rDeadZone	REAL	2
Input Const	rMaxW	REAL	25
Input Const	rW2	REAL	25
Input Const	rTo2	REAL	40
Input Const	rW1	REAL	20
Input Const	rTo1	REAL	30
Input Const	rManValue	REAL	0
Input Const	eManModeN	eManNum	eManNum.Auto
Output	rSetpoint	REAL
Output	bOverthrust	BOOL