Identifying a human-centred BAS
Specifying a BAS that is simple to use requires attention to the human-centred design features in the system’s software, control module, and wall units.
Software
Anyone who has learned a new software program knows it is often a trial-and-error process, with frequent reference to online manuals and calls to tech support to figure out “where is the X?”, “how do I do Y?” and “what is a Z?” Too often, programmers design software to make it easier for the computer to run it, than for the user to make sense of it.
While it is somewhat easier for someone who knows a word processing program, for example, to learn another word processor, many building professionals will not have encountered BAS software before. This makes it especially important the program be intuitive. A well-designed program can enable a new user to open up the BAS software for the first time and immediately see and understand the status of various building systems, and make adjustments to them. In addition to enabling the user to more fully operate the BAS, a simple-to-use program saves training time and costs.
One of the most important advances in BAS software design has been the introduction of graphical interfaces, rather than text entry and output systems. Many BAS now use schematic images to show building equipment, its operating status (e.g. heating or cooling) and what the environmental conditions are in various building spaces—such as temperature, relative humidity (RH), and CO2 concentration. As with other types of software, however, the program might not incorporate human-centred design elements.
Some building control manufacturers maintain user-testability labs to evaluate their BAS software in detail. Software usability testing is an iterative process informing all stages of the design process, and is not just having people try out a near-final beta program and asking them about what they think. Instead, it involves careful observation and measurement of the person’s performance, and noting where they have difficulties, from the earliest stages of software design. At each stage, the programmer makes adjustments and then retests the software until the program is intuitive. Design revisions might include:
- refinements to icon style, size, and placement;
- restructuring the menu tree;
- changing colour coding;
- redrawing equipment schematics; and
- similar enhancements.
In addition to changes resulting from usability testing, another simplifying feature introduced in leading BAS software in 2014 is the use of HTML5. This latest web-creation language empowers facility managers to remotely access the BAS from any Internet-connected device—including tablets, smartphones, and desktop computers—without the time and hassle of installing third-party software plug-ins.
Control module
An essential simplifying feature of any BAS is a control module that incorporates the BACnet protocol. Developed by the American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE), BACnet is a data communication protocol for building automation and control networks. It has become the industry’s open standard for BAS and numerous building systems.
“Capabilities vital to [building automation] applications were built into BACnet from the beginning in order to ensure the highest possible level of interoperability in an environment possibly involving multiple vendors and multiple types of building systems,” according to the Institute of Electrical and Electronics Engineers (IEEE).
Today, BACnet-enabled BAS can monitor and control building systems ranging from HVAC to lighting, electrical outlets, access control, life safety, vertical circulation, and many others. This interoperability greatly simplifies work for facility managers, as they can manage nearly all building systems from one integrated platform. For example, they can schedule a building’s HVAC equipment and lighting using one tool, rather than having to synchronize schedules across different control systems.
To further enhance interoperability, advanced BAS control modules incorporate multiple communications protocols such as BACnet, Tridium’s Niagara Framework, or LonTalk.
