BAC_GenWthT_01

Functional description

The template BAC_GenWthT_01 reads the measured outside temperature via the global variable g_WthT_rPrVal.

The measured outside temperature is used to calculate an averaged or attenuated outside temperature. This is made available to other templates via the global variable g_WthTDamp_rPrVal.

The BACnet object WthTLmtCrit describes the global variable g_WthTLmtCrit. It describes an outside temperature value below which the frost protection mode should be activated in the systems.

The SpFrost AV object is used to describe the global variable g_H_SpFrost. This global value can be used to assign a setpoint for frost protection operation to one or more plants.

For the application of many other templates it is necessary to position this template once!

Interface

BAC_GenWthT_01 1:

Block diagram

BAC_GenWthT_01 2:

Program description

Instance

Type

Task

WthT

FB_BACnetAVDisplay

AV object for displaying the current outside temperature

WthTLmtCrit

FB_BACnetAVSetpoint

AV object for entering and providing a global value for the critical outside temperature

SpFrost

FB_BACnetAVSetpoint

AV object for input and provision of a global frost protection setpoint

DlyEn

TON

Delays reading of the first temperature value by 2 seconds after the start of the PLC

Avrg

FB_BA_TiAvrg

The function block Avrg measures the outside temperature every 15 minutes (900 seconds) and writes the value into a FIFO buffer (first in first out). The buffer has capacity for 96 elements. This results in a timeframe of 24 hours for averaging of the outside temperature.

WthTDamp

FB_BACnetAVDisplay

Output of the value of the averaged outside temperature

Version history

Version number

Comments

1.0.1

First release