BAC_AC_SpRmTH_02

Application

The template BAC_AC_SpRmTH_02 is a simple set value program for an air conditioning plant with room or extract air cascade control for temperature and humidity.
There is a basic room temperature set value SpT_Y2_3. There is no energy-neutral zone between a lower set value (heating mode) and an upper set value (cooling mode). An outside temperature-dependent offset of the basic room temperature set value is realized via a curve function (summer/winter compensation).

The relative room humidity set values (%) are entered via the BACnet AV objects SpHHumf (humidification) and SpHDehumf (dehumidification). There is an energy-neutral zone between the lower set value (humidification) and the upper set value (dehumidification), which is monitored via the function SpHSupVis.

The two set values for the relative room humidity are converted within the template via the current room temperature to two set values for the absolute room humidity (g/kg), SpXHumf (humidification) and SpXDehumf (dehumidification).

Interface

BAC_AC_SpRmTH_02 1:

System diagram

BAC_AC_SpRmTH_02 2:

Block diagram

BAC_AC_SpRmTH_02 3:

VAR_Input

rRmT     : REAL;  

rRmT: Measured value of the room temperature

VAR_OUTPUT

rSpT          : REAL;  
rSpXHumf      : REAL;
rSpXDehumf    : REAL;
rSpHHumf      : REAL;
rSpHDehumf    : REAL;

rSpT: Calculated set value for the room temperature

rSpXHumf: Set value absolute humidity; humidification

rSpXDehumf: Set value absolute humidity; dehumidification

rSpHHumf: Set value relative humidity; humidification

rSpHDehumf: Set value relative humidity; dehumidification

Program description

Instance

Type

Task

SpT_X1

FB_BACnetAVSetpoint

Input of the value for interpolation point X1

SpT_X2

FB_BACnetAVSetpoint

Input of the value for interpolation point X2

SpT_X3

FB_BACnetAVSetpoint

Input of the value for interpolation points X3

SpT_X4

FB_BACnetAVSetpoint

Input of the value for interpolation point X4

SpT_Y1

FB_BACnetAVSetpoint

Input of the value for interpolation point Y1

SpT_Y2_3

FB_BACnetAVSetpoint

Input of the value for interpolation points Y2/Y3. The value is the base setpoint value

SpT_Y4

FB_BACnetAVSetpoint

Input of the value for interpolation point Y4

T_Scale

FB_BA_Chrct04

The function block calculates the set value characteristic curve for the current room temperature, depending on the outside temperature.

BAC_AC_SpRmTH_02 4:

SpT

FB_BACnetAVDisplay

Output of the calculated room temperature set value.

SpHHumf

FB_BACnetAVSetpoint

Input of the relative room humidity set value for humidification (%).

SpHDehumf

FB_BACnetAVSetpoint

Input of the relative room humidity set value for dehumidification (%).

SpHSupVis

FB_BA_SpSupVis

The function block is used for controlling the energy-neutral zone between the two set values SpHDehumf and SpHHumf

SpXHumf_HX

FB_BA_HX

This function block is used to calculate the set value for the absolute room humidity (humidification). For calculating the value, the room temperature, the set value for the relative humidity SpHHumf and the barometric air pressure are required.

SpXHumf

FB_BACnetAVDisplay

Output of the calculated absolute room humidity set value for humidification (g/kg).

SpXDehumf_HX

FB_BA_HX

This function block is used to calculate the set value for the absolute room humidity (dehumidification). For calculating the value, the room temperature, the set value for the relative humidity SpHDehumf and the barometric air pressure are required.

SpXDehumf

FB_BACnetAVDisplay

Output of the calculated absolute room humidity set value for dehumidification (g/kg).

Version history

Version number

Comments

1.0.1

First release