FB_BA_AC_PlantCmd_AHU_1st_10

The template represents the plant command of an air conditioning system without humidification and dehumidification.

The function block PlantControl is the core of the plant command system. It serves as a higher-level plant control unit for the connected aggregates.

The corresponding switch-on or switch-off commands and their priority are determined for each aggregate according to the specified plant operation mode eOpMode and the information in the control matrix of the PlantControl unit.

The bidirectional communication to the aggregates of the air conditioning system takes place via the array arrAggregate, see Principle diagram plant.

The parameterization of the control matrix is done in the methods below this template.

	The initialization of the template takes place within the method FB_Init.

Block diagram

Principle diagram plant

Syntax

FUNCTION_BLOCK FB_BA_AC_PlantCmd_AHU_1st_10 EXTENDS FB_BA_View
VAR_INPUT
  eOpMode               : E_BA_AC_OpMod01;
END_VAR
VAR_OUTPUT
  ePltStp               : E_BA_AC_PlantStep01;
  bStepCtrlUp           : BOOL;
  bStepCtrlDown         : BOOL;    
END_VAR
VAR_IN_OUT
  arrAggregate          : ARRAY [1..MAX(1,BA_Param.nMaxAggregate)] OF ST_BA_Aggregate;
END_VAR
VAR_INPUT CONSTANT
  DmpDlyCls             : FB_BA_AV_Op;
  SuAFanDlyOn           : FB_BA_AV_Op;
  ExtAFanDlyOn          : FB_BA_AV_Op;
  TempCtrlDlyOn         : FB_BA_AV_Op;
  PltStp                : FB_BA_MV_Op;
  PlantControl          : FB_BA_PlantControl;
END_VAR
VAR_INPUT CONSTANT PERSISTENT
  bInit                 : BOOL := TRUE;
END_VAR
VAR
  MMuxStart             : FB_BA_MMUX_B16;
  MMuxProfile           : FB_BA_MMUX_UDI16;
  MMuxPltStp            : FB_BA_MMUX_UDI16;
END_VAR

Inputs

Name	Type	Description
eOpMode	E_BA_AC_OpMod01	Input of the current operation mode eOpMode, see template FB_BA_AC_OpMod1St.

Outputs

Name	Type	Description
ePltStp	E_BA_AC_PlantStep01	Output of the current plant step of the air conditioning system.
bStepCtrlUp	BOOL	Indicates that the order of the step sequence control is in the rising state.
bStepCtrlDown	BOOL	Indicates that the order of the step sequence control is in the falling state.

Inputs/outputs

Name	Type	Description
arrAggregates	ARRAY [1..MAX(1,BA_Param.nMaxAggregate)] OF ST_BA_Aggregate	The array contains a bidirectional data and command structure for each aggregate. When the step sequence control is switched up or down, the switching command determined for each aggregate is transferred via the bidirectional communication structure arrAggregate. Feedback from the aggregates for switching the step sequence control up or down is transmitted to the PlantControl via the communication structure.

Name

Type

Description

arrAggregates

ARRAY [1..MAX(1,BA_Param.nMaxAggregate)] OF ST_BA_Aggregate

The array contains a bidirectional data and command structure for each aggregate.

When the step sequence control is switched up or down, the switching command determined for each aggregate is transferred via the bidirectional communication structure arrAggregate. Feedback from the aggregates for switching the step sequence control up or down is transmitted to the PlantControl via the communication structure.

Inputs CONSTANT

Name	Type	Description
DmpDlyCls	FB_BA_AV_Op	AV object for entering the value to delay the closing of the dampers during shutdown of the air conditioning plant, to take into account the overrun time of the fans during plant shutdown.
SuAFanDlyOn	FB_BA_AV_Op	AV object for entering a value for the start-up delay of the supply air fan when the air conditioning plant is switched on.
ExtAFanDlyOn	FB_BA_AV_Op	AV object for entering a value for the start-up delay of the extract air fan when the air conditioning plant is switched on.
TempCtrlDlyOn	FB_BA_AV_Op	AV object for entering a value for delayed temperature control enable.
PltStp	FB_BA_MV_Op	The MV object shows the current step of the plant's step sequence control.
PlantControl	FB_BA_PlantControl	The function block represents the higher-level plant control of a step sequence control of aggregates. The function block ensures that the individual aggregates of a plant are switched on or off sequentially one after the other in a certain order.

Inputs CONSTANT PERSISTENT

Name	Type	Description
bInit	BOOL	The variable is used to call the initialization methods for the control matrix in the CallInit method. After starting the controller, the variable is set to FALSE after a PLC cycle and this state is saved persistently.

Name

Type

Description

bInit

BOOL

The variable is used to call the initialization methods for the control matrix in the CallInit method.

After starting the controller, the variable is set to FALSE after a PLC cycle and this state is saved persistently.

Variables

Name	Type	Description
MMuxStart	FB_BA_MMUX_B16	The multiplexer uses the plant operation mode eOpMode to define whether the air conditioning system is started or stopped.
MMuxProfile	FB_BA_MMUX_UDI16	The multiplexer uses the plant operation mode eOpMode to define the control profile of the PlantControl.
MMuxPltStp	FB_BA_MMUX_UDI16	The multiplexer evaluates the steps of the step sequence control and transfers them to the MV object PltStp for display at management level.

Methods

Name	Definition location	Description
CallInit	Local	Calling the initialization methods for parameterization of the control matrix of the plant control unit.
ProfileDescription	Local	Used to initialize the parameter array arrProfileDescription of the plant control unit.
ProfileParameter0x	Local	Initialization of a part of the multidimensional profile parameter array arrProfileParameter of the control unit.
StepDescription	Local	Used to initialize the parameter array arrStepDescription of the plant control unit.

Requirements

Development environment	Necessary function
TwinCAT from v3.1.4024.56	TF8040 \| TwinCAT Building Automation from V5.8.0.0

Further Information