How BEMS Are Gaining New Friends

The principal function of a BEMS is to automatically control and monitor a premises building services plant. But this does not mean that a system can simply be left to get on with it - which has sometimes been assumed in the past. Though they perform no control actions, a system’s operator interfaces are a vital part of any installation.

The operator interface is needed to change operational parameters, such as temperature and time settings, and for refining control strategies in the light of experience. Importantly, it also provides access to a mass of information concerning plant/environmental conditions and energy usage. Such data will often highlight sources of energy waste that had previously gone unnoticed. Indeed, many BEMS have saved as much in this way as they have through energy efficient control.

Often referred to as a supervisor, the main operator interface on a modern BEMS generally takes the form of a Windows-based software package running on a desktop PC. Data tends to be presented in easy to comprehend pictorial or graphical formats and there may be a whole series of other features designed to aid the user - eg, dynamic graphics, data record and playback and automatic energy analysis.

Though these interfaces have proved excellent management tools, they have traditionally been poor at meeting the needs of those who are not regular computer users. One reason for this is their Windows format and the bafflement it can cause the novice.

It is not however necessary to forsake the Windows operating environment in order to improve user friendliness. This can be achieved by designing applications which avoid its more confusing features, such as having to contend with multiple windows. (It was exactly this approach which Trend took when developing its new generation of BEMS supervisors.)

On the latest supervisors, operators can locate the information they are looking for by making use of a set of graphical ‘maps’ which provide a simple overview of the information available. This has made supervisor operation a much more intuitive process for the occasional user.

Of equal importance is the fact that what users see depends on who they are - or more specifically what their access rights are. For instance, the security guards in a building might only be able to call up a single page allowing them to switch lights on an off. In contrast, the building services engineer would be granted access to a much wider range of screen displays and control functions.

Data entry operations, such as setting and changing building occupation times, have been simplified too and improvements have also been made to allow a clearer view of alarm status.

When these latest developments have been combined with the facility for touch screen operation the resultant supervisor is able to cater for even the most technophobic. And if such an interface is designed for wall-mounting - rather than to run on a desktop PC - it is able to serve as a communal facility. As such, it becomes available to a greater number of people.

The latest supervisors have effectively made BEMS accessible to a whole new group of people, such as retail staff, security personnel and caretakers - individuals who are unlikely to be computer literate and may have regarded BEMS as being beyond their comprehension.

Others who will benefit include the likes of office staff and teachers, who may be computer literate but are not BEMS ‘aware’. In addition to providing such people with a convenient way of controlling their workspace environment, the new supervisors are an excellent tool for involving them in energy saving campaigns.

As well as becoming easier to operate, BEMS have been getting ever more user friendly when it comes to engineering and commissioning them. Much of this stems from a breakthrough made at the beginning ofthe nineties - the development of the first graphical configuration tool designed for intelligent building controls. This original piece of software, the award-winning ‘ACE’ AutoCAD package, was created by Trend specifically for use with its own BEMS. Now most other leading manufacturers have introduced similar products.

As well as allowing control strategies to be created on a computer screen (using ‘drag and drop’ from function menus), such tools are able to automatically generate the application programs for the controllers - a task previously done manually using a text editor, which was very time consuming. Moreover, the strategies they produce are error-free and they also print out a complete set of documentation.

Software-based commissioning tools are a more recent development. One such tool enables the strategy from a working controller, complete with live data, to be viewed  graphically. The engineer is able to see at a glance whether the controls are working as they should, with the result that considerable time savings can be made.

There are also programs which allow the tuning of control loops to be largely automated. Tuning by conventional means can be a very laborious exercise and as a result it is sometimes ignored all together, though this usually means a high cost has to be paid through reduced energy efficiency and increased maintenance (the latter due to constantly cycling plant).

BEMS engineering ‘toolkits’ have grown considerably in recent years and their contents continue to be enlarged. Some now include a range of software aids which have been designed to assist with system maintenance and modification. For example, Trend’s ‘Change Tracker’ tool allows comparison of the current strategy in a controller with that on the as-fitted file - ie, to see if any undocumented changes have been made. Without knowledge of such changes, a visiting service engineer could waste hours.

With BEMS now simpler to operate, install and maintain, there is no longer any reason why the technology’s considerable energy saving potential can not be fully exploited.