Building Automation Systems (BAS) – Guide to Selecting Building Controls

By Sean Weber with Dynamix Energy Services

In a world of flashy sales brochures, confusing marketing terms, and ever changing technologies it can be overwhelming to know what is important when selecting and buying a building automation and controls. The important items that building owners should not compromise on are listed below.

Controls Architecture

Controls architecture refers to overall BAS network structure, hierarchy, and physical layout of the system. A typical architecture has some type of supervisory controller that is housed on a PC or server. When purchasing a new control system make sure the controls architecture allows for expansion. Whether it is the addition of few devices or an entire facility it is important to make sure the control systems have extra capacity.

Supported Communication Protocols

Data is communicated between devices through a Communication Protocol. It is the language that a particular device is able to interpret and forward to other devices on the network. Some common protocols are BACnet, Lon, and Modbus.

When selecting a control system choose one where the front end is compatible with a number of protocols. This will give greater flexibility as building equipment and devices change over time.

Graphics and Accessibility

Building graphics refer to the building automation interface. This is the primary way that building managers and maintenance staff interact with the building automation system.

Look for a control system that utilizes an HTML5 based graphics package. HTML5 is compatible with all internet browsers and is mobile friendly allowing for the ability to access the BAS on all devices.

Trends and Alarming

Do not consider any control system that does not provide trending and alarming capabilities. Trends refer to the ability to store and view historical data such as room temperature for the past 5 days. Alarms are alerts to problems within the facility.

Open System

When selecting a control system look for a truly open system… one that will not lock you into a single contractor. This means a system that utilizes a non‐proprietary open protocol such as BACnet. A system that utilizes control products that are available from multiple suppliers, and a system that utilizes open software not locked down by licenses or configuration tools only available from a few select companies.

Training and Support

There are numerous control systems that provide all the critical characteristics listed above, and for this reason the single biggest differentiator when selecting a control system is the training and support provided after the installation by the controls contractor. Never install a new controls system without having detailed plan and associated cost for training and support after the installation is complete.

Editor’s Note: Sean Weber is an Energy Engineer with Dynamix Energy Services. Sean may be contacted at 614‐443‐1178 ext. 246 or E‐mail to: sweber@dynamix‐