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

Functional description

General

This function block is used to control / regulate a heat generator depending on the demand of the heat generator xEn, the supply setpoint temperature rSetPtTemp and the supply temperature rFdT. The enabling / blocking of the heat generator is carried out via output xHB (FALSE = blocking, TRUE = enabling). The supply temperature control (analogously also boiler temperature control) is carried out by means of two power controllers (P controller, slow and fast) via outputs xMoreHB and xLessHB. Control enable is delayed (setpoint / parameter udiWaitControl) after the operating feedback (xFb = TRUE) of the heat generator. The following function blocks are mainly used:

ControlP

Out3P

OperatingHours

ManBin

Enabling / blocking of the heat generator

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

Temperature control of the heat generator

Control enable is delayed (duration = udiWaitControl, display - remaining time: tOnControlDelay) after the active operating message (xFb = TRUE) of the heat generator. The blocking of temperature control occurs immediately after the inactive operating message (xFb = FALSE) of the heat generator (switch-off value: rYDisabled). The two internal power controllers (P controller, slow and fast, output range each -100.0 - 100.0 %) are enabled / blocked simultaneously. (Setpoint = supply setpoint temperature rSetPtTemp, actual value = supply temperature rFdT). The control signals of both power controllers are fed to the output controller in minimum value selection (forwarding the signal with the lower 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 outputs xMoreHB or xLessHB. The constant pulse duration for the two outputs can each be freely set (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 (fast P controller: gain factor rKpBig, slow P controller: 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 operating 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 mode On
X	eMANBIN.ManOff	FALSE	manual override module in manual mode Off

Legend: X = any

Collective fault xAlarm

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

Collective message automatic mode xAuto

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

• 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 operating message is active (xFb = TRUE).

Write access to the counter values

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

Requirement for using the Burner3P function block

For correct operation, the TimeRead2 function block must be used.

Current calculated power of the heat generator rPos

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

Feedback of the heat generator power rU

The current actual power of the heat generator can be connected at 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 = any

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