FB_BA_AC_ErcPl_02
![FB_BA_AC_ErcPl_02 1:](Images/png/9007214562491019__Web.png)
The template represents the open-loop and closed-loop control of an energy recovery system with a plate heat exchanger.
The main tasks of the template are:
- Control of the supply air temperature
- Minimum limitation of exhaust air temperature
- Anti-icing of the heat exchanger by means of a differential pressure monitor above the heat exchanger
- Control of a damper
- Control of a bypass damper
- Collecting and evaluating safety-relevant faults using the PlantLock
- To be part of the step sequence control of an air conditioning system, see Aggregates
The exhaust air minimum limiter TExhACtrl and the frost protection program IcePrtcRamp limit the control value of the temperature sequence controller TSuACtrl of the energy recovery system via a minimum selection to prevent the heat exchanger from icing up.
Principle diagram 01
The diagram shows the intended use of the template with the plant elements involved.
![FB_BA_AC_ErcPl_02 2:](Images/png/15307751947__Web.png)
Principle diagram 02
The diagram shows the integration of the template within a plant.
![FB_BA_AC_ErcPl_02 3:](Images/png/9007214562494859__Web.png)
![]() | The initialization of the template takes place within the method FB_Init. |
Block diagram
![FB_BA_AC_ErcPl_02 5:](Images/png/9007214562489099__Web.png)
Syntax
FUNCTION_BLOCK FB_BA_AC_ErcPl_02 EXTENDS FB_BA_View
VAR_INPUT
fSpTSuA : REAL;
fTSuA : REAL;
bSyncTSuACtrl : BOOL;
fSyncTSuACtrl : REAL;
bDehumf : BOOL;
fTExhA : REAL;
fTExtA : REAL;
fTWth : REAL;
END_VAR
VAR_OUTPUT
fPresentValue : REAL;
eAction : E_BA_Action;
bActiveSeqCtrl : BOOL;
END_VAR
VAR_IN_OUT
stTSeqLink : ST_BA_SeqLink;
END_VAR
VAR_INPUT CONSTANT
TSuACtrl : FB_BA_AC_PreHtrTSuACtrl;
TExhACtrl : FB_BA_PID_Sp;
DiffPrssSwi : FB_BA_SensorBinary;
IcePrtcRamp : FB_BA_PID_Sp;
Dmp : FB_BA_ActuatorAnalog;
ByDmp : FB_BA_ActuatorAnalog;
PlantLock : FB_BA_PlantLock;
END_VAR
VAR
bPrioSfty : BOOL;
bPrioCrit : BOOL;
PrioSwiVal : FB_BA_PrioSwi_B04;
Inv : FB_BA_Chrct02;
END_VAR
Inputs
Name | Type | Description |
---|---|---|
fSpTSuA | REAL | Setpoint of the supply air temperature |
fTSuA | REAL | Measured value of the supply air temperature |
bSyncTSuACtrl | BOOL | Pulse for synchronization of the sequence controller TSuACtrl. |
fSyncTSuACtrl | REAL | Value for the synchronization of the supply air sequence controller TSuACtrl. |
bDehumf | BOOL | Input dehumidification mode active. This state has an effect on the sequence control in the supply air temperature control TSuACtrl template. |
fTExhA | REAL | Measured value exhaust air temperature |
fTExtA | REAL | Measured value extract air temperature |
fTWth | REAL | Measured value weather temperature |
Outputs
Name | Type | Description |
---|---|---|
fPresentValue | REAL | Current value of the bypass damper system |
eAction | E_BA_Action | The output of the control direction of the supply air controller TSuACtrl is required within an air conditioning system for the setpoint strategy. |
bActiveSeqCtrl | BOOL | The sequence controller TSuACtrl is the active one in the sequence control. |
Inputs/outputs
Name | Type | Description |
---|---|---|
stSeqLink |
The data and command structure is the link between the supply air temperature sequence controller Ctrl and the supply air temperature sequence controller TSeqLink of an air conditioning system. |
Inputs CONSTANT
Name | Type | Description |
---|---|---|
TSuACtrl | The function block represents the supply air temperature control of energy recovery and is part of the temperature sequence control of an air conditioning system. The control signal is forwarded to the analog control of damper Dmp via a minimum selection. | |
TExhACtrl | FB_BA_PID_Sp | The function block represents the exhaust air temperature control for the anti-icing of the plate heat exchanger. |
DiffPrssSwi | The binary input object represents a differential pressure monitor above the heat exchanger. This is used for anti-icing and activates the ramp function IcePrtcRamp. | |
IcePrtcRamp | FB_BA_RampLimitIncrease | The function block represents the anti-icing of the plate heat exchanger using an increasing ramp function. This function is activated by means of the differential pressure monitor DiffPrssSwi. |
Dmp | The function block is used to control the analog damper of the plate heat exchanger. | |
ByDmp | The function block is used to control the analog bypass damper of the plate heat exchanger. | |
PlantLock | When the function block is called, the relevant faults of the event-enabled objects are collected and output at this and lower levels of the template. These relevant faults cause specific switching actions via the variables bPrioSfty and bPrioCrit in the template. The parameterization of the lock priority of the event-enabled objects can be found in the FB_init of this template. |
Variables
Name | Type | Description |
---|---|---|
bPrioSfty | BOOL | The variable is an evaluation of the Safety lock priority of the event-enabled objects in the project structure and causes targeted switching actions in the template when a relevant fault is triggered. |
bPrioCrit | BOOL | The variable is an evaluation of the Critical lock priority of the event-enabled objects in the project structure and causes targeted switching actions in the template when a relevant fault is triggered. |
PrioSwiVal | The priority switch PrioSwiVal determines the switching conditions and enables for the supply air temperature control TSuACtrl and the differential pressure control for anti-icing IcePrtcDiffPrssCtrl using the aggregate function block Aggregate and the global variable list Priority. |
Requirements
Development environment | Necessary function |
---|---|
TwinCAT from v3.1.4024.35 | TF8040 | TwinCAT Building Automation from V5.0.0.0 |
Inputs/outputs
Name | Type | Description |
---|---|---|
stSeqLink | The data and command structure is the link between the supply air temperature sequence controller Ctrl and the supply air temperature sequence controller TSeqLink of an air conditioning system. | |
stAggregate | 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. |