Application domain: SMART BUILDINGS

Building Automation could be considered a potential application domain for the application of IEC 61499 technologies.

Here is an extract from 'The IEC 61499 Function Block Standard: Launch and Takeoff', by Thomas Strasser et al.

• paper available at www.holobloc.com/papers/iec61499/61499_LTO.pdf

The distributed nature of the building automation domain, and its need for distributed intelligence, make it a natural fit for the application of IEC 61499 technology. The Austrian company nxtControl, a software 20 vendor for IEC 61499 based systems, is actively involved in several projects in building automation for office buildings, hotels, and shopping malls as well as data centers. The following challenges for the implementation of a building control system were similar in almost all of these projects:

• The hardware setup of the building automation system has a distributed nature in which various controllers, sometimes from different vendors, are in use.
• Different communication protocols have to be used, for example KNX, DALI, ENOCEAN
• The control engineers have to deal with weak or often changing requirements, and the reality at the building site is often very different from that envisioned during the design and planning phase
• Cost pressures and a very tight time frame are challenges for the control engineers during the design and implementation of the control system.

These challenges demand a very flexible software architecture for the building automation system. Therefore, in order to offer the greatest impact for system integrators and control engineers, the vendor has developed an IEC 61499 ­based component library of the most­used devices and functions in commercial buildings. For missing devices and functions, the vendor and customers together are continuously working on additional specifications in order to extend the existing IEC 61499 building automation library. This library consists of software objects including not only control logic but also visualization, I/O connection and documentation, which are very important aspects for the realization of control solutions. The vendor has therefore introduced a so­called Composite Automation Type (CAT) which includes all these elements, on the basis of the IEC 61499 FB model. Once all the objects are available the engineering and commissioning of the automation for the buildings can be done very quickly. It is simple drag­and­drop engineering. The engineer makes an instance of a library element (CAT), drags it in the IEC 61499­compliant editor, connects the different objects as needed, and the same instance is then dropped in the HMI editor. This combined approach drastically speeds up the design and development procedure in the building domain. For example, a distributed control solution for a training center with 140 cells (i.e., office rooms) on 4 floors has been implemented in a very short time. The automation solution comprises the control of the heating, ventilation, air­conditioning, lighting, electrical distribution system, and the monitoring of the fire smoke exhaustion system as well as the integration of a web­based visualization system of the training center building. In total, 12 embedded controllers equipped with an IEC 61499 runtime system connected to about 1200 I/Os are used for the control solution.