BAC_AC_SpRmTH_03

Application

The template BAC_AC_SpRmTH_02 is a set value program for an air conditioning plant with room or extract air cascade control for temperature and humidity.

There are two basic room temperature set values (SpTHtgY1, SpTColY1), with an energy-neutral zone between the lower set value (heating mode) and the upper set value (cooling mode). The energy-neutral zone is monitored via the function SpHSupVis.
An outside temperature-dependent offset of the basic room temperature set values is realised via two curve functions (summer/winter compensation).

The relative room humidity set value (%) is entered with BACnet AV object SpH.
There is no energy-neutral zone between a lower set value (humidification) and an upper set value (dehumidification) for humidity control.
The set value for the relative room humidity SpH is converted into a set value for the absolute room humidity (g/kg) SpX within the template via the current room temperature.

Interface

BAC_AC_SpRmTH_03 2:

System diagram

Block diagram

VAR_Input

rRmT     : REAL;

rRmT: Measured value of the room temperature

VAR_OUTPUT

rSpTHtg    : REAL;  
rSpTCol    : REAL;  
rSpX       : REAL;
rSpH       : Real;

rSpTHtg: Calculated heating set value for the room temperature

rSpTCol: Calculated cooling set value for the room temperature

rSpX: Calculated set value of the absolute room humidity

rSpH: Set value for the relative room humidity

Program description

Instance	Type	Task
SpTColX1	FB_BACnetAVSetpoint	Input of the value for interpolation point SpTColX1 cooling
SpTColX2	FB_BACnetAVSetpoint	Input of the value for interpolation point SpTColX2 cooling
SpTColY1	FB_BACnetAVSetpoint	Input of the value for interpolation point SpTColY1 cooling. The value is the base cooling setpoint value
SpTColY2	FB_BACnetAVSetpoint	Input of the value for interpolation point SpTColY2 cooling
SpTColScale	FB_BA_Chrct04	The function block calculates the characteristic cooling set value curve for the current room temperature, depending on the outside temperature.
SpTCol	FB_BACnetAVDisplay	Output of the calculated room temperature cooling set value
SpTHtgX1	FB_BACnetAVSetpoint	Input of the value for interpolation point SpTHtgX1 heating
SpTHtgX2	FB_BACnetAVSetpoint	Input of the value for interpolation point SpTHtgX2 heating
SpTHtgY1	FB_BACnetAVSetpoint	Input of the value for interpolation point SpTHtgY1 heating. The value is the base heating setpoint value
SpTHtgY2	FB_BACnetAVSetpoint	Input of the value for interpolation point SpTHtgY2 heating
SpTHtgScale	FB_BA_Chrct04	The function block calculates the characteristic heating set value curve for the current room temperature, depending on the outside temperature.
SpTHtg	FB_BACnetAVDisplay	Output of the calculated room temperature heating set value
SpTSupVis	FB_BA_SpSupVis	The function block is used for controlling the energy-neutral zone between the two set values SpTCol and SpTHtg
SpH	FB_BACnetAVSetpoint	Input of the set value for the relative room humidity (%).
SpHX	FB_BA_HX	This function block is used to calculate the set value for the absolute room humidity. For calculating the value, the room temperature, the set value for the relative humidity SpH and the barometric air pressure are required.
SpX	FB_BACnetAVDisplay	Output of the calculated absolute room humidity set value (g/kg).

Version history

Version number	Comments
1.0.1	First release