FB_BA_WeatherParameter
The template calculates various values from the measured value of the outside temperature, which are required system-wide for the control and regulation of heating, ventilation and air conditioning systems.
The object SpFrstProtec is used to enter a frost protection setpoint. The frost protection setpoint is used system-wide in all HVAC templates with a water-side frost protection.
The function block TWthLowLimitHys calculates whether the outside temperature is below the critical value of TWthLowLimitVal. Depending on the value of the variable bTWthLowLimit, the frost protection function of the HVAC systems in the building is activated.
The weather-related enable of the heating systems is not dependent on the current, but on the damped outside temperature. The outside temperature is attenuated using the function block Average (formation of a sliding average value). The object TWthDamped is used to display the value of the damped outside temperature.
The function block TWthDampedLowLimitHys is used to check whether the damped outside temperature is below a value that will enable the heating systems in the building. The global weather-related enable is displayed with the object "TWthDampedLowLimit" and written to the variable bTWthDampedLowLimit for further processing in other templates.
 | The initialization of the template takes place within the method FB_Init. |
Block diagram
Syntax
FUNCTION_BLOCK FB_BA_Settings EXTENDS FB_BA_View
VAR_INPUT
fTWth : REAL;
END_VAR
VAR_OUTPUT
fSpFrstProtec : REAL;
fTWthLowLimit : REAL;
bTWthLowLimit : BOOL;
fTWthDamped : REAL;
bTWthDampedLowLimit : BOOL;
END_VAR
VAR_INPUT CONSTANT
SpFrstProtec : FB_BA_AV_Op;
TWthLowLimitVal : FB_BA_AV_Op;
TWthLowLimit : FB_BA_BV_Op;
TWthDamped : FB_BA_AV_Op;
TWthDampedLowLimit : FB_BA_BV_Op;
END_VAR
VAR
TWthLowLimitHys : FB_BA_Swi2P;
Average : FB_BA_TiAvrg;
TWthDampedLowLimitHys : FB_BA_Swi2P;
END_VAR
Outputs
Name | Type | Description |
|---|---|---|
fSpFrstProtec | REAL | Frost protection setpoint, e.g. for heating circuits in protection mode. |
fTWthLowLimit | REAL | Lower limit value of the outside temperature. Below this value, all frost protection functions in HVAC systems are activated. |
bTWthLowLimit | BOOL | The output shows the operating message Outside temperature lower limit. The variable is TRUE if the outside temperature is below the value of fTWthLowCrit. |
fTWthDamped | REAL | Current value of the damped outside temperature. |
bTWthDampedLowLimit | BOOL | The output shows the operating message Outside temperature damped lower limit. The variable is TRUE if the damped outside temperature is below the value of fTWthLowCrit. |
Inputs CONSTANT
Name | Type | Description |
|---|---|---|
SpFrstProtec | Analog value object for entering the frost protection setpoint, e.g. for heating circuits in protection mode. | |
TWthLowLimitVal | Analog value object for entering the lower limit value of the outside temperature. Below this value, all frost protection functions in HVAC systems are activated. | |
TWthLowLimit | Binary object displaying the Outside temperature lower limit operating message. | |
TWthDamped | Analog value object for displaying the damped outside temperature. Below this value, all frost protection functions in HVAC systems are activated. | |
TWthDampedLowLimit | Binary object displaying the Outside temperature damped lower limit operating message. |
Variables
Name | Type | Description |
|---|---|---|
TWthLowLimitHys | Two-point switch which converts the outside temperature fWth into a binary switching signal for TWthLowLimit. | |
Average | The Average uses the outside temperature fWth to determine the damped outside temperature fTWthDamped. | |
TWthDampedLowLimitHys | Two-point switch which converts the damped outside temperature fTWthDamped into a binary switching signal for TWthDampedLowLimit. |
Requirements
Development environment | Necessary function |
|---|---|
TwinCAT from v3.1.4024.35 | TF8040 | TwinCAT Building Automation from V5.0.0.0 |