Architecture

BACnet (Building Automation Control network) is a data communication protocol developed by ASHRAE (American Society of Heating, Refrigerating, and Air Conditioning Engineers) for managing building automation devices. The BACnet driver uses the standard Niagara Framework® network architecture to implement this protocol. The Niagara Drivers Guide documents the Framework’s general approach.

Network types

A remote station’s BacnetNetwork is unique because it simultaneously supports multiple BACnet link layer types using different BACnet communication protocols:

  • BACnet/IP
  • BACnet/SC
  • BACnet/Ethernet
  • BACnet MS/TP for host platforms that are based on QNX.

Thus, depending on the configuration, a BacnetNetwork may proxy BACnet devices that not only reside in different BACnet networks, but are also accessed using different physical ports on the host controller.

Client/server operations

BACnet is based on a client/server model. The client is in charge and tells the server what and how to deliver data. The server responds to client requests. A remote host platform may function as both a client and a server.

Server operations

If the host platform is licensed as a BACnet server, it can export any number of selected types of objects from the station (regardless of location) to appear as BACnet objects in a client. As such, these objects can service client requests from any networked BACnet device. This includes exporting schedules, calendars and histories. Exported histories appear externally as BACnet Trend Log objects.

 NOTE: BACnet AWS Supervisor (BacnetAwsNetwork) and BACnet OWS Supervisor (BacnetOwsNetwork) stations are not typically licensed for server side (export) operations. 

The BACnet driver, running in a remote controller, is capable of managing both server and client operations concurrently. In special cases, you may configure a remote controller station to run as a BACnet server only.