FanControl

FanControl (FB)

FUNCTION_BLOCK FanControl

Short description

Control of a variable-speed fan (controlled variables e.g. absolute pressure, differential pressure) Additional functions: manual overrides, service switch, operating hours counter, operation monitoring, air shortage monitoring, limit value monitoring Typical application: control of a fan with a frequency inverter

Representation

Function description

General

This function block controls a variable-speed fan via a continuous control signal rHA. The general enablement of the fan is effected via the request xEn and the enable signal xHB. The speed control is carried out by a freely parameterizable PI controller, to which the setpoint rSetPoint and the actual value rActValue are supplied and from which the controller's control signal is generated. The following function blocks are essentially used:

ControlPI

ManBin

ManNum

TwoPointFun

Ramp

CTime

AirShortage

OperatingHours

Enable - fan before manual override xAB

The enable - fan before manual override xAB is activated ( = TRUE ) if the following conditions are met simultaneously: Case 1: &#xNAN;xEn = TRUE &#xNAN;xMSwitch = TRUE xAlarmControl = FALSE Case 2: &#xNAN;xEn = TRUE &#xNAN;xMSwitch = TRUE xAlarmControl = TRUE &#xNAN;xAlarm = FALSE In all other situations the enable - fan before manual override is xAB is not activated ( = FALSE ).

Enable - fan after manual override xHB

The enable - fan after manual override xHB corresponds to the enable - fan before manual override xAB, additionally extended by a manual override module. The enablement can generally only occur if the forced lockout of the fan after manual override is not active ( xForce = FALSE ) and the collective fault message 2 is not active ( = FALSE ).

xAB	eManModeB	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 = any

Message of the service switch xMSwitch

xMSwitch = TRUE: Service switch has not been triggered ( normal state ) &#xNAN;xMSwitch = FALSE: Service switch has been triggered ( fault state )

Forced lockout of the fan after manual override xForce

xForce = FALSE: no forced lockout ( normal state ) &#xNAN;xForce = TRUE: forced lockout ( exceptional state )

Operating hours and switch-on events udiOperatingHours and udiCountFb

The number of operating hours and switch-on events are recorded ( = counting process active ) if the operation signal of the fan xFb is active and at the same time the collective fault message 2 is not active ( = FALSE ). The results are available at the counter outputs udiOperatingHours and udiCountFb and available.

Write access to the counter values

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

Prerequisite for the use of the FanControl function block

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

Date / time of the last operation of the fan dtLastFb

At the output dtLastFb the current date/time is available during the counting process. At the output dtLastFb the date/time at the end of the last counting process is available outside the counting process. At the output dtLastFb is output before the first counting process with the initialization value DT#1970-1-1-0.0.0.

Operation monitoring xAlarmFb

The operation monitoring can be enabled ( = TRUE ) or inhibited ( = FALSE ) by the setpoint / parameter xFbControl When monitoring is inhibited, the fault message of the operation monitoring xAlarmFb is always inhibited ( = FALSE ). When monitoring is enabled, the fault message of the operation monitoring xAlarmFb is activated ( = TRUE ) if the following states are present simultaneously for a minimum duration udiFbControlTime : &#xNAN;xHB and xFb = unequal ( enable state and operating state do not match ) &#xNAN;eAOO = HVACTYPES.eManBin.Auto ( manual override - hardware for the automatic enable ) xFbControl = TRUE ( operation monitoring is enabled ) The fault message of the operation monitoring xAlarmFb is reset ( = FALSE ) if at least one of the following conditions is met: &#xNAN;eAOO = HVACTYPES.eManBin.Auto ( switching back to automatic mode of the manual override - hardware ) &#xNAN;xQuit = TRUE ( reset of the monitoring is active ) xFbControl = FALSE ( operation monitoring inhibited )

Air shortage monitoring xAlarmPFb

The air shortage monitoring is performed by evaluating the states at the inputs xPFb and xFb. The fault message of the air shortage monitoring xAlarmPFb is activated ( = TRUE ) if, with monitoring enabled ( xPFbControl = TRUE ) during the air shortage monitoring alarm delay udiPFbControlTime the input xPFb is continuously not active ( = FALSE ) and the input xFb is active ( = TRUE ). The fault message of the air shortage monitoring xAlarmPFb is deactivated ( = FALSE ) if the conditions for activation are no longer met and at the same time monitoring is inhibited ( xPFbControl = FALSE ) and/or the reset of the fault messages (monitorings) is active ( xQuit = TRUE ).

Collective fault message 1 - output xAlarm

The collective fault message is activated ( = TRUE ) if at least one of the conditions described below is met. &#xNAN;xAlarmIn = TRUE ( fan fault message is active ) &#xNAN;xAlarmFB = TRUE ( fault from the operation monitoring ) &#xNAN;xAlarmPFB = TRUE ( fault from the air shortage monitoring ) &#xNAN;xMSwitch = FALSE ( service switch in Off position ) &#xNAN;xAlarmMaxValue = TRUE ( maximum value exceeded ) &#xNAN;xAlarmMinValue = TRUE ( minimum value undershot ) In all other cases the collective fault is not active ( = FALSE ).

Collective fault message 2

The collective fault message is activated ( = TRUE ) if at least one of the conditions described below is met. &#xNAN;xAlarmIn = TRUE ( fan fault message is active ) &#xNAN;xAlarmFB = TRUE ( fault from the operation monitoring ) &#xNAN;xAlarmPFB = TRUE ( fault from the air shortage monitoring ) &#xNAN;xMSwitch = FALSE ( service switch in Off position ) &#xNAN;xAlarmMaxValue = TRUE ( maximum value exceeded ) In all other cases the collective fault is not active ( = FALSE ).

Resetting the fault messages xQuit

Any rising edge ( FALSE > TRUE ) at the input xQuit clears any existing fault messages of the following monitoring facilities Air shortage monitoring Operation monitoring Minimum value monitoring Maximum value monitoring

Control process

General The actual value *rActValue* is scaled by a linear characteristic curve and fed to the PI controller. The setpoint *rSetPont* is filtered by a signal ramp, scaled by a linear characteristic defined by 2 points and fed to the PI controller. The output signal of the PI controller is filtered by another signal ramp and fed to the output for the control signal *rHA*. Enable The enablement of the control process takes place with a time delay of **udiWaitControl** after the fan operating signal becomes active ( *xFb* = TRUE ). The blocking of the control process occurs without time delay after the fan operating signal becomes inactive ( *xFb* = FALSE ). Setpoint The setpoint is fixed to 0.0 if the fan enable is not active ( *xHB* = FALSE ). The setpoint is taken from the input *rSetPoint*, filtered by a signal ramp and scaled by a linear function defined by 2 points ( prerequisite: *xHB* = TRUE ). The relevant parameters of the signal ramp are individually adjustable ( maximum variation = (**rMaxValue** / 5) per 10s ). The relevant parameters of the linear function are individually adjustable ( input range in Pa: 0.0 - **rMaxValue**, output range in %: 0.0 - 100.0 ). Actual value The actual value is taken from the input *rActValue* and scaled by a linear function defined by 2 points. The relevant parameters of the linear function are individually adjustable ( input range in Pa: 0.0 - **rMaxValue**, output range in %: 0.0 - 100.0 ). Limitation of the PI controller control signal **rYMin** and **rYMax** The controller's control signal ( PI controller ) is limited by the adjustable limits **rYMin** and **rYMax** ( minimum value monitoring not active ) or **rSubstitueHA** ( minimum value monitoring active ). Signal ramp of the controller's control signal The control signal from the PI controller is filtered by a signal ramp. The relevant parameters of the signal ramp are individually adjustable ( maximum variation = **rYRampVariation** per **rYRampTime** ). Parameters of the PI controller The parameters essential for the control behavior can be provided from outside. They must be adapted depending on the control path. A sensible basic parameterization has already been made, which is sufficient in many application cases. **rYMin** = Lower absolute limit of the controller output signal **rYMax** = Upper absolute limit of the controller output signal **rOffset** = Setpoint offset - controller **rKp** = Gain factor - controller **rTn** = Reset time - controller in s **eAction** = Action direction of the controller ( Inverted, Direct ) **rInitValue** = Initialization value for the control signal **rYDisabled** = Control signal when controller is inactive Signals of the PI controller The signals calculated during the control process ( before the signal ramp ) are available to monitor the control operation. *rPiDiff* = Control deviation at the controller *rPiPartP* = Proportional part of the control signal *rPiPartI* = Integral part of the control signal *xPiLimitActiv* = Status - limit exceedance - control signal ( FALSE = Off, TRUE = On ) Controller control signal If the controller is not enabled, the switch-off value **rYDisabled** is passed to the controller control signal output ( prerequisite: **ePiManModeN** = eMANNUM.Auto ) and limited by the absolute limits. The integral part is set to 0.0. If the controller is enabled, the controller control signal is calculated ( prerequisite: **ePiManModeN** = eMANNUM.Auto ) and limited by the absolute limits. With the default action **eAction** ( = eControlMode.Inverted ) a too low actual value ( actual value < setpoint ) causes a continuous increase of the controller control signal value.

Control signal fan before manual override rAA

The control signal of the fan before manual override rAA is primarily taken from the controller output signal after the signal ramp. However, this output signal is additionally limited downward during the fan request ( xHB = TRUE ) by the lower absolute limit **rYMin* downwards. In the event of a minimum value undershoot ( xAlarmMinValue = TRUE ) the control signal before manual override rAA is replaced by the fixed value rSubstitueHA .

Control signal fan after manual override rHA

The control signal of the fan after manual override rHA corresponds to the control signal of the fan before manual override rAA additionally extended by a manual override module.

rAA	eManModeN	rHA	Notes
X	eMANNUM.Auto	rAA	Manual override module in automatic
X	eMANNUM.Man	eManValue	Manual override module in manual operation

Legend: X = any

Operating mode for the controller output signal ePIManModeN

The parameter ePiManModeN allows switching the controller output signal from automatic to manual operation and vice versa. In manual operation the controller output signal takes over the manual operation output signal ePiManValue.

ePiManModeN	Output signal	Function
eMANNUM.Auto	Signal according to formula / switch-off value	Automatic mode - output signal
eMANNUM.Man	ePiManValue	Manual mode - output signal

Maximum pressure monitoring xAlarmMaxValue

The output xAlarmMaxValue is activated ( = TRUE ) if the current actual value rActValue exceeds the adjustable maximum value rMaxValue . The output xAlarmMaxValue is deactivated ( = FALSE ) if the current actual value rActValue exceeds the adjustable maximum value rMaxValue falls below and at the same time a rising edge ( FALSE > TRUE ) is detected at the input xQuit .

Minimum pressure monitoring xAlarmMinValue

The output xAlarmMinValue is activated ( = TRUE ) if the following conditions are simultaneously permanently fulfilled for a minimum duration of udiWaitMinValue ( 1.0 - 600.0 s ): &#xNAN;xFb = TRUE ( fan is in operation ) &#xNAN;eAO = HVACTYPES.eManNum.Auto ( operating mode of the manual override - hardware for the control signal in automatic mode ) &#xNAN;rHA > rMinHAValue ( control signal is greater than the minimum value ) &#xNAN;rActValue < rMinValue ( actual value is smaller than the minimum value ) No rising edge ( FALSE > TRUE ) was detected at the input xQuit recognized The output xAlarmMinValue is deactivated ( = FALSE ) if the conditions for activation are no longer met and at the same time at the input xQuit .

Combined message automatic mode xAuto

The combined message automatic mode xAuto is activated ( = 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

• Setpoint / parameter ePiManModeN = eMANNUM.Auto

CODESYS

InOut:

Scope	Name	Type	Initial
Input	xEn	BOOL
Input	xForce	BOOL	FALSE
Input	xFb	BOOL
Input	xPFb	BOOL
Input	xMSwitch	BOOL	TRUE
Input	xAlarmIn	BOOL
Input	eAOO	eManBin	eManBin.Auto
Input	eAO	eManNum	eManNum.Auto
Input	rPoti	REAL
Input	rU	REAL
Input	xQuit	BOOL	FALSE
Input	rActValue	REAL
Input	rSetPoint	REAL
Output	xHB	BOOL
Output	xAB	BOOL
Output	rHA	REAL
Output	rAA	REAL
Output	xAlarmFb	BOOL
Output	xAlarmPFb	BOOL
Output	xAlarmMinValue	BOOL
Output	xAlarmMaxValue	BOOL
Output	dtLastFb	DT
Output	udiOperatingHours	UDINT
Output	udiCountFb	UDINT
Output	xAlarm	BOOL
Output	xAuto	BOOL
Output	rPiDiff	REAL
Output	rPiPartP	REAL
Output	rPiPartI	REAL
Output	xPiLimitActiv	BOOL
Input Const	rMaxValue	REAL	490
Input Const	rSubstituteHA	REAL	30
Input Const	udiWaitMinValue	UDINT	60
Input Const	rMinHAValue	REAL	20
Input Const	rMinValue	REAL	20
Input Const	tYRampTime	TIME	TIME#1m0s0ms
Input Const	rYRampVariation	REAL	30
Input Const	udiWaitControl	UDINT	30
Input Const	rYMax	REAL	100
Input Const	rYMin	REAL	20
Input Const	rTn	REAL	60
Input Const	rKp	REAL	1
Input Const	rOffset	REAL	0
Input Const	rInitValue	REAL	20
Input Const	rYDisabled	REAL	0
Input Const	eAction	eControlMode	eControlMode.Inverted
Input Const	ePiManValue	REAL
Input Const	ePiManModeN	eMANNUM	eMANNUM.Auto
Input Const	udiPFbControlTime	UDINT	60
Input Const	xPFbControl	BOOL	TRUE
Input Const	xAlarmControl	BOOL	TRUE
Input Const	udiFbControlTime	UDINT	60
Input Const	xFbControl	BOOL	TRUE
Input Const	rManValue	REAL
Input Const	eManModeN	eMANNUM	eMANNUM.Auto
Input Const	eManModeB	eMANBIN	eMANBIN.Auto

Methods:

mQuit

mResetOperatingHours

Structure:

• mQuit (Method)

• mResetOperatingHours (Method)