107
17.0
Connecting to a BACnet system
BACnet stands for Building Automation and Control Networks (
http://www.bacnet.org
). It is a
communication protocol for monitoring and controlling different building regulation systems,
which include heating, ventilation, lighting control, access control, and fire detection systems.
The BACnet protocol uses a common communication format to let these different systems
communicate with each other. A tutorial is available at
http://www.bacnet.org
.
BACnet uses a peer-to-peer architecture where any device can send service requests to any
other device. Protocol services include Who-Is, I-Am, Who-Has and I-Have. Any BACnet
object can perform these service requests. BACnet services can provide event notifications
such as troubles or input activations.
The FleX-Net™ system can interface with other systems that communicate through BACnet.
FleX-Net™ does not query other BACnet systems. Instead, other BACnet systems can
request current values from the FleX-Net™ system. FleX-Net™ only replies to requests or
sends out notifications of new events.
17.1
BACnet Objects
A BACnet
object
is “a collection of information related to a particular function that can be
uniquely identified and accessed over a network in a standardized way”. Each object has an
object ID and a set of properties.
A confusion of terminology can arise when describing FleX-Net™ under the BACnet model. In
the fire alarm industry, the term
device
refers to things such as detectors, strobes, and alarms.
With BACnet, the entire FleX-Net™ system is a device with many objects.
Object
refers to all
the fire devices, system statuses and switches connected to the FleX-Net™ system.
Figure 78 BACnet objects
BACnet classifies objects into different types. For example, fire devices are divided into
categories such as binary inputs, binary outputs, analog inputs and analog outputs. Every
object has an object identifier, an object name, and other properties. Some properties are
required and some are optional.
FleX-Net™
DEVICE
Physical
Devices
OBJECTS
System
Status
OBJECTS
Switches
OBJECTS
OBJECTS
...........