BACnet (Building Automation Control Network) Standard

BACnet (Building Automation Control Network) Standard

BACnet is a standard communication protocol as defined in ANSI/ASHRAE Standard 135-1995. The BACnet protocol has many applications in light and commercial buildings including HVAC control and management.

BACnet protocol is a set of rules that govern data flow and allows for intercommunication among devices on a network irrespective of the manufacturer/vendor.

 

See below various HVAC systems interconnected to a BMS system for central control.

 


 

BACnet operates on two main concepts:

                BACnet services: for information purposes

                BACnet objects: for action i.e reading, writing, or performing functions on the devices.

 

BACnet generally have two types of networks:

  1. BACnet MS/TP (Master-Slave/Token Passing)- protocol uses standard serial ports (RS-232/RS-485) on microcontrollers. Utilizes token-passing process from one master node to another (makes its communication slow).

In case you may be having issues with your BACnet MS/TP, here is an example of how to troubleshoot issues.

Alternative to wired BACnet MS/TP, you can use wireless BACnet (or Wireless Modbus) to ease you setup and reduce troubleshooting time in case of issues.

  1.  BACnet TCP/IP (Internet Protocol)- operates in IP-enabled devices. More and more new controllers and devices on the market are IP-enabled, including but not limited to actuators, sensors, light switches, gateways, cameras, and thermostats.