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Introduction
Introduction
About this Manual
First time users can obtain the most essential information for quick installation and set-up in these chapters:
Introduction
How to Install
How to Configure the System
Application Example
For more detailed information including the full range of set-up options and diagnosis tools, refer to the chapters:
How to Control the TR200
How to Access TR200 Parameters
Parameters
Troubleshooting
Technical Overview
BACnet (Building Automation and Control Network) is an open data communications protocol, American Na-
tional Standard (ANSI/ASHRAE 135-1995). BACnet provides a means by which computer-based control equip-
ment from different manufacturers can work together. BACnet is designed to handle many types of building
controls, including HVAC, lighting, security, fire, access control, maintenance and waste management. BACnet
permits flexibility for expansion and different equipment combinations.
Conformance Classes, Function Groups and the PICS: Evaluating the capabilities of a BACnet device is poten-
tially a formidable task, given the great choice of objects, properties and services, which can be implemented,
as well as the fact that it is not necessary for every BACnet device to have a full BACnet implementation in order
to carry out its task. ASHRAE's BACnet Committee recognized this problem and responded with aids to evalu-
ation in the form of "Conformance Classes", "Function Groups" and the "Protocol Implementation Conformance
Statement" (PICS).
The BACnet protocol defines six levels of conformance classes, each of which specifies the minimum subset of
services implemented on the device. The lowest level, Conformance Class 1, requires only that the BACnet
device contain a device object and that it be able to execute (respond to) a ReadProperty service request. Each
successive conformance class level adds service requests that must be executable by the device, as well as the
service requests it must be able to initiate. Conformance Class 6 requires 21 types of service requests (of the 32
overall) to be implemented, of which 20 must be initiable and 17 executable. Conformance class thus provides
a measure of the device's ability to communicate.
Function groups specify a combination of objects and services necessary to carry out certain building automa-
tion functions. They are specified independently of conformance class, though the implementation of some of
the function groups automatically confers some conformance class higher than 1.
TR200 BACnet 2-1