Convergence of Building Automation and the IT World, FHNW School of Computer Science

BACnet, IoT, Java, Websockets, X.509-Zertifikate

Pilot implementation and validation of the emerging BACnet/IT communication standard

Digitalization in the control and monitoring of heating, ventilation, and lighting systems in large commercial buildings is already well advanced. To enable digital devices from different manufacturers to communicate with one another, standardized bus systems with their own transmission protocols are used, often based on dedicated cabling. One of these is BACnet.

One version of this standard, BACnet/IP, uses mass-produced standard components from Internet technology instead of expensive proprietary cabling standards.

To further reduce costs while opening up new possibilities, the goal is to use not only the same cabling technology in the future, but even the very same cables that provide building occupants with Internet access. A prerequisite for this is that the communication protocols of future building automation systems also adopt established Internet standards, so as not to conflict with the IT network management of building users.

Zusammen mit Fachleuten von Siemens Building Technologies hat eine Forschungsgruppe des IMVS die Entwicklung des Standards BACnet/IT unterstützt, der den Geräten der Gebäudeautomation BACnet-kompatible Kommunikation auf der Basis von Internet-Kommunikationsprotokollen bietet. Während im internationalen Standardisierungskomitee der ASHRAE an den Definitionen gearbeitet wurde, wie BACnet-Geräte zukünftig über das Internet kommunizieren werden, hat das Projektteam diese Definitionen mit eigenen Umsetzungen erprobt und mit eigens entwickelten Testwerkzeugen vermessen. Die dabei gewonnenen Erkenntnisse konnten so in die Standardisierungsarbeiten zurückfliessen.

Initially, for example, the use of a pool of WebSockets as transmission channels was not envisaged. WebSockets allow bidirectional connections to be established through firewalls and enable low-latency communication. The latter is particularly important because, unlike many other Internet of Things (IoT) applications, building automation devices must be able to communicate directly with each other quickly and without delay.

Compliance with IT network management rules is essential, as building automation and office automation will share the same network infrastructure in the future.

If devices are generally accessible from the open Internet worldwide, security must be explicitly taken into account. Devices may only execute commands from authenticated and trustworthy partners. In collaboration with researchers from Lucerne University of Applied Sciences and Arts, a security concept was therefore developed that enables end-to-end security based on X.509 certificates.

The BACnet/IT communication stack implemented in Java by IMVS is available as an open-source project and can be used by industry partners to develop their own standard-compliant devices(github.com/fhnw-BACnet-IT).