Burner3P

Burner3P (FB)

FUNCTION_BLOCK Burner3P

Short description

Control of a heat generator (temperature control via binary control commands More / Less) 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 = disabled, TRUE = enabled ). The flow temperature control (analogously also boiler temperature control) is performed by two power controllers (P-controllers, slow and fast) via the outputs xMoreHB and xLessHB. The enabling of the control is delayed (setpoint / parameter udiWaitControl ) after the running feedback ( xFb = TRUE ) of the heat generator. The following function blocks are essentially used:

ControlP

Out3P

OperatingHours

ManBin

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 running feedback ( 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 (switch-off value: rYDisabled ). The two internal power controllers (P-controllers, slow and fast, output range each -100.0 - 100.0 %) are enabled / disabled simultaneously. (Setpoint = flow setpoint temperature rSetPtTemp, actual value = flow temperature rFdT ). The control signals of both power controllers are forwarded to the output controller in a minimum-value selection (forwarding the signal with the smaller value) in the range -100.0 - 100.0 %. The output controller finally generates output signals for a 3-point actuator (pulse-width modulation, integration interval = tIntegration ) with the outputs xMoreHB or xLessHB. The constant pulse duration for the two outputs is freely adjustable in each case ( tImpulsOpen or tImpuls Close ), the variable pulse pauses are determined by the output controller. The two power controllers can be configured individually and independently of each other (P-controller fast: gain factor rKpBig, P-controller slow: gain factor rKpTiny ).

Manual override of the digital outputs

All digital control outputs after manual override ( xHB, xMoreHB*, xLessHB ) can be operated either in automatic mode ( eMANBIN.Auto ) or in one of the two manual operation 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

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 eAOOMore = HVACTYPES.eManBin.Auto

• Input eAOOLess = HVACTYPES.eManBin.Auto

• Setpoint / parameter eManModeB = eMANBIN.Auto

• Setpoint / parameter eManModeBMore = eMANBIN.Auto

• Setpoint / parameter eManModeBLess = eMANBIN.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 Burner3P function block

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

Currently calculated output of the heat generator rPos

The current calculated output of the heat generator is shown at the output rPos in the range 0.0 - 100.0 %. For this, the correct specification of the actuator travel time between minimum and maximum output ( tDuration ) is required. No repositioning to a reference position takes place.

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.

Inactive state ( xEn = FALSE )

xHB	xAB	xMoreHB	xMoreAB	xLessHB	xLessAB	rPos	tOnDelay	tOnControlDelay	dtLastFb	udiOperatingHours	udiCountFb	xAlarm	xAuto	Notes
FALSE ( eManModeB = eManBin.Auto )	FALSE	FALSE ( eManModeBMore = eManBin.Auto )	FALSE	FALSE ( eManModeBLess = eManBin.Auto )	FALSE	0.0 %	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	eAOOMore	eManBin	eManBin.Auto
Input	eAOOLess	eManBin	eManBin.Auto
Input	rFdT	REAL
Output	xHB	BOOL
Output	xAB	BOOL
Output	xMoreHB	BOOL
Output	xMoreAB	BOOL
Output	xLessHB	BOOL
Output	xLessAB	BOOL
Output	rPos	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	tDuration	TIME	TIME#1m0s0ms
Input Const	tIntegration	TIME	TIME#100ms
Input Const	tImpulsClose	TIME	TIME#1s0ms
Input Const	tImpulsOpen	TIME	TIME#1s0ms
Input Const	rKpTiny	REAL	0.6
Input Const	rKpBig	REAL	4
Input Const	rOffset	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	eManModeBLess	eMANBIN	eMANBIN.Auto
Input Const	eManModeBMore	eMANBIN	eMANBIN.Auto
Input Const	eManModeB	eMANBIN	eMANBIN.Auto