BurnerP

BurnerP (FB)

FUNCTION_BLOCK BurnerP

Short description

Control of a heat generator (temperature control via analog power signal 0.0 - 100.0 %) Typical application: heat generation

Representation

Function description

General

This function block is used to control / regulate a heat generator depending on the demand of the heat generator xEn, the flow setpoint temperature rSetPtTemp and the flow temperature rFdT. The enable / disable of the heat generator is done via the output xHB ( FALSE = lockout, TRUE = enable ). The flow temperature control (analog also boiler temperature control) is performed by a power controller (PI controller) via the analog output rHa in the range of rYMin to rYMax. The enabling of the controller is delayed (setpoint / parameter udiWaitControl ) after the running feedback ( xFb = TRUE ) of the heat generator. The following function blocks are essentially used:

ControlPI

OperatingHours

ManBin

ManNum

Enable / disable of the heat generator

The enabling of the heat generator ( xAB = TRUE, xHB = TRUE ( eManModeB = eManBin.Auto )) occurs if the flow temperature rFdT the sum of flow setpoint temperature rSetPtTemp and setpoint / parameter rSwitchOnPoint falls below, at the same time the general enable xEn active ( = TRUE ) and the minimum off time is not active. The disabling of the heat generator ( xAB = FALSE, xHB = FALSE ( eManModeB = eManBin.Auto )) occurs if the flow temperature rFdT the sum of flow setpoint temperature rSetPtTemp and setpoint / parameter rSwitchOffPoint exceeds and at the same time the general enable xEn active ( = TRUE ). A minimum off time (duration = udiTimeMinOff, display - remaining time: tOnDelay ) is always inserted between two consecutive operating cycles. The minimum off time always begins with the falling edge ( TRUE > FALSE ) at the input xFb.

Temperature control of the heat generator

The enabling of the temperature control is delayed (duration = udiWaitControl, display - remaining time: tOnControlDelay ) after the active operation message ( xFb = TRUE ) of the heat generator. The disabling of the temperature control occurs immediately after the inactive running feedback ( xFb = FALSE ) of the heat generator (power signal - heat generator before manual override rAA in the locked state = rYDisabled ). The internal power controller (PI controller, output range: rYMin to rYMax ) is enabled/disabled with the temperature control. (setpoint = flow set temperature rSetPtTemp, actual value = flow temperature rFdT ). The parameters of the internal power controller can be configured individually: Power controller - upper absolute limit of the output signal in % : rYMax Power controller - lower absolute limit of the output signal in % : rYMin Power controller - reset time in s : rTn Power controller - gain factor : rKp Power controller - offset temperature in °C : rOffset Power controller - initialization value for the output signal in % : rInitValue Power controller - switch-off value in % : rYDisabled The output signal of the power controller is fed directly to the output rAA supplied.

Manual override of the digital output xHB

The enable/disable of the heat generator ( xHB ) can be operated either in automatic mode ( eMANBIN.Auto ) or in one of the two manual modes ( eMANBIN.ManOn, eMANBIN.ManOff ).

xAB	eMANBIN	xHB	Notes
FALSE	eMANBIN.Auto	FALSE	Manual override module in automatic
TRUE	eMANBIN.Auto	TRUE	Manual override module in automatic
X	eMANBIN.ManOn	TRUE	Manual override module in manual operation On
X	eMANBIN.ManOff	FALSE	Manual override module in manual operation Off

Legend: X = don't care

Manual override of the analog output rHA

The output signal of the power controller ( rHA ) can be operated either in automatic mode ( eMANNUM.Auto ) or in manual mode ( eMANNUM.Man ).

rAA	eMANNUM	rHA	Notes
Value	eMANNUM.Auto	Value	Manual override module in automatic
X	eMANNUM.Man	rManValue	Manual override module in manual operation

Legend: X = don't care

Aggregate fault xAlarm

The aggregate fault xAlarm is active ( = TRUE ) if the fault message of the heat generator xAlarmIn is active ( = TRUE ). In all other situations the aggregate fault xAlarm is not active ( = FALSE ).

Collective automatic mode message xAuto

The collective automatic mode message xAuto is set active ( = TRUE ) if the following conditions are met simultaneously:\

• Input eAOO = HVACTYPES.eManBin.Auto

• Input eAO = HVACTYPES.eManNum.Auto

• Setpoint / parameter eManModeB = eMANBIN.Auto

• Setpoint / parameter eManModeN = eMANNUM.Auto

Operating hours counter - heat generator

The operating hours counter ( udiOperatingHours, udiCountFb ) for the heat generator is active when the running feedback is active ( xFb = TRUE ).

Write access to the counters

Via the path ‘InstanceName._OperatingHours.udiOperatingHours’ or ‘InstanceName._OperatingHours.udiCountFb’ a write access to both counter values is possible.\

Prerequisite for using the function block BurnerP

The use of the TimeRead2 function block is required for correct operation.

Feedback of the heat generator output rU

The current actual Output of the heat generator can be connected to the input rU . This input is currently not used for control and regulation purposes.

Feedback of the manual value for the power signal from the manual override - hardware rPoti

The feedback of the manual value can be at the input rPoti . This input is currently not used for control and regulation purposes.

Inactive state ( xEn = FALSE )

xHB	xAB	rHA	rAA	tOnDelay	tOnControlDelay	dtLastFb	udiOperatingHours	udiCountFb	xAlarm	xAuto	Notes
FALSE ( eManModeB = eManBin.Auto )	FALSE	rYDisabled ( eManModeN = eManNum.Auto )	rYDisabled	old value	old value	old value	old value	old value	State of xAlarmIn	old value	xEn = FALSE

Legend: X = don't care

CODESYS

InOut:

Scope	Name	Type	Initial
Input	xEn	BOOL
Input	rSetPtTemp	REAL
Input	xFb	BOOL
Input	rU	REAL	0
Input	xAlarmIn	BOOL
Input	eAOO	eManBin	eManBin.Auto
Input	eAO	eManNum	eManNum.Auto
Input	rPoti	REAL
Input	rFdT	REAL
Output	xHB	BOOL
Output	xAB	BOOL
Output	rHA	REAL
Output	rAA	REAL
Output	tOnDelay	TIME
Output	tOnControlDelay	TIME
Output	dtLastFb	DT
Output	udiOperatingHours	UDINT
Output	udiCountFb	UDINT
Output	xAlarm	BOOL
Output	xAuto	BOOL
Input Const	udiTimeTOFxFb	UDINT	7
Input Const	rYMax	REAL	100
Input Const	rYMin	REAL	0
Input Const	rTn	REAL	200
Input Const	rKp	REAL	2
Input Const	rOffset	REAL	0
Input Const	rInitValue	REAL	0
Input Const	rYDisabled	REAL	0
Input Const	udiWaitControl	UDINT	3
Input Const	rSwitchOffPoint	REAL	2.5
Input Const	rSwitchOnPoint	REAL	-2.5
Input Const	udiTimeMinOff	UDINT	3
Input Const	rManValue	REAL	0
Input Const	eManModeN	eMANNUM	eMANNUM.Auto
Input Const	eManModeB	eMANBIN	eMANBIN.Auto