FB_BA_AC_TCasCtrl_01

The template is used for room temperature control by means of room-supply air cascade.

It consists of a master controller for calculating the supply air temperature setpoint for the aggregates heater, cooler and energy recovery.

The supply air temperature sequence control is enabled with the variable bOn by evaluating the receive block of the step sequence control Aggregate.

Principle diagram01

Principle diagram02

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

Block diagram

Syntax

FUNCTION_BLOCK FB_BA_AC_TCasCtrl_01 EXTENDS FB_BA_View
VAR_INPUT
  fSpTRm        : REAL;
  fTRm          : REAL;
END_VAR
VAR_OUTPUT
  fSpHtg        : REAL;
  fSpCol        : REAL;
  fSpErc        : REAL;
  fMax          : REAL;
  fMin          : REAL;
  bOn           : BOOL;
END_VAR
VAR_IN_OUT
  stAggregate   : ST_BA_Aggregate;
END_VAR
VAR_INPUT CONSTANT
  SpHtg         : FB_BA_AV_Op;
  SpCol         : FB_BA_AV_Op;
  SpErc         : FB_BA_AV_Op;
  Ctrl          : FB_BA_Loop;
  Aggregate     : FB_BA_Aggregate;
END_VAR
VAR
  PrioSwiVal    : FB_BA_PrioSwi_UDI04;
  MuxCmd        : FB_BA_MMUX_B04;
  MuxSpHtg      : FB_BA_MMUX_R04;
  MuxSpCol      : FB_BA_MMUX_R04;
  MuxSpErc      : FB_BA_MMUX_R04;
END_VAR

Inputs CONSTANT

Name	Type	Description
fSpTRm	REAL	Input variable for the room temperature setpoint.
fTRm	REAL	Input variable to which the room temperature is applied. The room temperature is the control value of the PID master controller Ctrl. If no room temperature is available, the outlet air temperature of a ventilation system can be used as control value.

Outputs

Name	Type	Description
fSpHtg	REAL	Calculated setpoint of the supply air temperature for the heater.
fSpCol	REAL	Calculated setpoint of the supply air temperature for the cooler.
fSpErc	REAL	Calculated setpoint of the supply air temperature. for energy recovery.
fMax	REAL	Upper value of the controller output limitation.
fMin	REAL	Lower value of the controller output limitation.
bOn	BOOL	The output shows the resulting result of the multiplexer MuxCmd. This is further processed within the ventilation system and is used to enable the supply air temperature sequence control.

Inputs/outputs

Name	Type	Description
stAggregate	ST_BA_Aggregate	Bidirectional aggregate structure via which the enables and switching values are transmitted to the evaluation function block of the step sequence control Aggregate. The aggregate structure transmits the recorded feedback signals up and down to the central plant control.

Inputs CONSTANT

Name	Type	Description
SpHtg	FB_BA_AV_Op	Analog value object for displaying the calculated room temperature setpoint heating.
SpCol	FB_BA_AV_Op	Analog value object for displaying the calculated room temperature setpoint cooling.
SpErc	FB_BA_AV_Op	Analog value object for displaying the calculated supply air temperature setpoint Energy recovery.
Ctrl	FB_BA_Loop	The LOOP object serves as a master controller for a room temperature control by means of a room-supply air cascade. It provides the supply air temperature setpoint.
Aggregates	FB_BA_Aggregate	The aggregate function block represents a receive block of a step sequence controller. Within the function block, the aggregate structure stAggregate is evaluated and integrated into the template using the inputs and outputs.

Variables

Name	Type	Description
PrioSwiVal	FB_BA_PrioSwi_UDI04	The priority switch uses the command structure stCmd to determine the modulation command for the multiplexer MuxCmd.
MuxCmd	FB_BA_MMUX_B04	The multiplexer determines the current switching command from the modulation command of the priority switch PrioSwiVal. The resulting output is sent to the output bOn. The multiplexer defines the enabling conditions of the PID master controller Ctrl.
MuxSpHtg	FB_BA_MMUX_R04	The multiplexer defines the setpoint heating fSpHtg depending on the priority switch PrioSwiVal.
MuxSpCol	FB_BA_MMUX_R04	The multiplexer defines the cooling setpoint fSpCol depending on the priority switch PrioSwiVal.
MuxSpErc	FB_BA_MMUX_R04	The multiplexer defines the setpoint energy recovery fSpErc depending on the priority switch PrioSwiVal.

Requirements

Development environment	Necessary function
TwinCAT from v3.1.4024.35	TF8040 \| TwinCAT Building Automation from V5.0.0.0