Concept of BACnet Objects: Simplifying Building Automation

 In BACnet (Building Automation and Control Networks), objects are fundamental entities used to represent different aspects of a building's automation and control system. BACnet defines several standard object types, each serving a specific purpose. These object types include:

1. Analog Input (AI): Represents a continuous, analog quantity, such as temperature or pressure.
2. Analog Output (AO): Represents a controllable output, such as a variable speed drive or a valve.
3. Analog Value (AV): Represents a settable analog quantity, similar to an AO but without control capabilities.
4. Binary Input (BI): Represents a binary (on/off) input, such as a switch or a sensor detecting presence.
5. Binary Output (BO): Represents a binary (on/off) output, such as a relay or a light switch.
6. Binary Value (BV): Represents a settable binary quantity, similar to a BO but without control capabilities.
7. Multi-state Input (MI): Represents an input with multiple discrete states, such as a selector switch.
8. Multi-state Output (MO): Represents an output with multiple discrete states, such as a damper position controller.
9. Multi-state Value (MV): Represents a settable multi-state quantity, similar to an MO but without control capabilities.
10. Device: Represents a physical device on the network, such as a controller, sensor, or actuator.

Each object type has properties that provide information about the object, such as its name, description, units, and current value. Objects are organized into a hierarchical structure within a BACnet system, making it easier to manage and access the various components of the system.

In the world of building automation, BACnet is a key player, enabling seamless communication between various devices and systems. At the heart of BACnet lies the concept of objects, which are instrumental in organizing and managing the wealth of information exchanged in a building automation network.

What are BACnet Objects?


Think of BACnet objects as digital representations of physical or logical entities within a building. These entities can range from simple sensors to complex control systems. Each object encapsulates a specific set of properties and behaviors, making it easier to interact with and manage them.

How Do Objects Work?

Let us consider a simple example to understand this better. Imagine a thermostat in a room, tasked with maintaining a comfortable temperature. In a BACnet-enabled system, the thermostat would be represented as an object. This object would have properties such as current temperature, setpoint temperature, and operating mode (heating or cooling).

Example Scenario:

1.     Object Type: The thermostat would be classified as an "analog input" object type in BACnet, as it deals with continuous values like temperature.

2.     Properties:   

·       Current Temperature: This property would hold the current temperature reading from the sensor.

·       Setpoint Temperature: Here, you would find the desired temperature set by the user.

·       Operating Mode: This property indicates whether the thermostat is set to heat, cool, or is off.

3.     Actions:           

•         Adjust Setpoint: An action that allows you to change the setpoint temperature.

Why are Objects Important?

Objects simplify the process of monitoring and controlling devices in a building automation system. By standardizing the way information is organized and exchanged, objects enable interoperability between different manufacturers' devices, ensuring seamless integration within a building ecosystem.


Conclusion

In essence, BACnet objects serve as the building blocks of a smart, interconnected building. By encapsulating devices and their properties in a standardized format, objects make it easier to manage, monitor, and control building systems. They pave the way for efficient and intelligent building automation, ultimately leading to enhanced comfort, energy savings, and operational efficiency.