TECHNOLOGY BASICS: What are Building Automation Systems?

Technology Overview
Monitor and control to maintain and save

A Building Automation System (BAS) consists of a building controller, software, network license, lower-level controllers, sensors, network components, and occupant interfaces (potentially from third party vendors) necessary to control and monitor building systems.

A typical BAS adds monitoring and control features to HVAC systems and administers this programming through a centralized computer or other networked device. A BAS can be programed to implement energy saving control strategies like pre-cooling, setbacks, scheduling, and occupancy-based setpoint changes. These programs can control when HVAC systems turn on/off, adjust temperature setpoints, and trigger faults/alarms when system components & sensors operate outside of pre-defined acceptable ranges.

Some BASs have automated demand response (ADR) features that automatically reduce the electricity used by building systems in response to demand response events issued by the utility or pricing signals provided by a web server. Changing temperature setpoints and dimming lights are two examples of system changes that may be implemented during demand response events. Another feature that some BASs offer is an application programming interface (API) that allows the BAS to use third-party information available online (like real-time weather or pricing data) to optimize building controls with respect to cost and performance.

A BAS consists of at least one dedicated hardware component (known as a building controller) that is connected to the building. This building controller acts as a router/gateway to communicate with a central computer or network through a local ethernet (or sometimes wireless) connection, and allows data to be sent and received from building systems. These BAS building controllers can offer a variety of communication options, such as open-source protocols or proprietary protocols. In addition, these building controllers can offer different signal types used to communicate with sensors, actuators, relays, or valves that require direct connection to their built-in input/output (I/O) terminals or I/O expansion modules. It is important to note that BAS manufacturers often offer other controllers to supplement the building controller. These replace the existing HVAC controllers, variable air volume (VAV) damper actuators, and/or thermostats, to provide monitoring and control features to otherwise proprietary, non-communicating or non-programable HVAC systems.

Beyond HVAC control, some of today’s BAS controllers may also be used to control and monitor other building systems like lighting, blinds, security, fire, etc.