Georg Neugschwandtner

Wireless Technologies in Home and Building Automation

The use of wireless technologies in automation systems offers attractive benefits, but introduces a number of new technological challenges. The paper discusses these aspects for home and building automation applications. Relevant standards are surveyed. A wireless extension to KNX/EIB based on tunnelling over IEEE 802.15.4 is presented. The design emulates the properties of the KNX/EIB wired medium via wireless communication, allowing a seamless extension. Furthermore, it is geared towards zero-configuration and supports the easy integration of protocol security.

Security in networked building automation systems

Enriching Building Automation Systems (BAS) with new services formerly provided by separate subsystems promises synergies, but increases demands on the BAS architecture. In particular, the integration of security subsystems significantly tightens security requirements on the protocol of a networked control system. First, this paper gives a survey on security in BAS. Possible threats and attacks are discussed. Weaknesses in the security mechanisms of important open networked BAS (LonWorks, BACnet, KNX/EIB) are summarized. Then, a security extension to KNX/EIB is presented. It includes several security mechanisms that guarantee data integrity, confidentiality and freshness, as well as authentication to provide secure process data and management communication. Relevant configuration related issues such as key management and distribution are also addressed.

Web Services in Building Automation: Mapping KNX to oBIX

Web services are a key technology for enabling interoperable machine-to-machine interaction over a network. They also lend themselves excellently to the integration of automation and IT systems. This paper discusses oBIX, a new standard for representing and accessing building automation (BA) data via Web services. It is shown how access to a BA system that follows the KNX protocol standard can be faithfully represented by way of oBIX entities. A prototype implementation of such a gateway is presented. The extensible nature of the oBIX data model is leveraged by using it to express the required KNX-oBIX mapping information as well. This approach allows a particularly clear and efficient gateway design.

A modular architecture for building automation systems

The deployment of building automation systems (BAS) allows to increase comfort, safety and security and to reduce operational cost. Today such systems typically follow a two-layered hierarchical approach. While control networks interconnect distributed sensors, actuators and controllers, a backbone provides the necessary infrastructure for management tasks hosted by configuration and management devices. In addition, devices interconnecting the control network with the backbone and the backbone with further networks (e.g., the Internet) play a strategic role. All BAS devices contributing to a particular functionality differ in their requirements for hardware. This paper discusses requirements for devices used in the building automation domain and presents our work in progress to assemble platforms with different purposes relying on a modular architecture.

Multicast communication in wireless home and building automation: ZigBee and DCMP

With an ever increasing performance, wireless technologies present a more and more attractive alternative to wired media. This is also true for home and building automation (HBA) systems. In HBA, large areas must be covered at low cost. This precludes the use of dedicated network infrastructure. At the same time, the allowable power consumption and thus transmission power of sensors in particular is severely restricted. Hence, efficient peer-to-peer communication schemes are required. Especially for multicast communication, optimized protocols can make a difference. Therefore, this paper shows how DCMP (dynamic core based multicast routing protocol for ad hoc wireless networks) can be used to improve multicast in ZigBee networks.

Congestion control in building automation networks: Considerations for KNX

Current standard network protocols for distributed building automation were designed before the advent of the cost efficient fast networking technologies that are popular today. While these technologies are of great benefit for the network backbone, the possibility of “fast” nodes on such media overwhelming “slow” nodes or network segments increasingly comes into focus. Besides discussing the issue on a generic level, this paper closely examines the situation for the KNX protocol standard and suggests possible ways of improvement.

Fire safety alarm transmission in networked building automation systems

Comparing the structure of a modern fire alarm system with the one of a networked Building Automation System (BAS) reveals important common characteristics. Both systems have nodes distributed in the building, communicating over an electric wire. They typically use the same cable for both communication and power supply of nodes, and both can be implemented using a similar network structure. This paper presents the work-in-progress regarding the implementation of safety-related functionality using the infrastructure of a networked BAS. It shows how the link layers of KNX/EIB and LonWorks can be adapted in a downward compatible way to ensure that safety related messages have priority over any other BAS traffic. In addition, a system-neutral protocol for the robust and timely transmission of fire alarm messages is proposed.

An Open Approach To Eib/Knx Software Development

Abstract: EIB/KNX is a field bus used in home and building automation. When building application programs for EIB/KNX nodes, one was hitherto faced with low-level constructs. To improve this situation, a RAD (Rapid Application Development) like approach was adopted. This model encapsulates the system software entities in a way which is inspired by the object-oriented paradigm. It also makes use of functional blocks to describe the application behaviour. To allow the roles of software developer and project engineer to be separated, the tool chain is designed for interfacing with an integration tool. The article discusses the work flow when building an EIB/KNX system and the resulting requirements on the tool chain. The GCC-based solution which was developed is presented. Specific challenges in porting the GNU tool chain to the standard microcontroller for EIB/KNX nodes are sketched. The implementation also includes an open PC-based EIB/KNX network access and management server. Copyright

Service interfaces for field-level home and building automation

Gateway functionality is a key point in leveraging the potential of a home or building automation network. High-level interfaces providing abstractions of field area network (FAN) functionality significantly reduce the effort involved in creating application-level solutions. Such interfaces are presented on two different levels of abstraction. First, an interface corresponding to the network layer of a FAN used in building automation (European installation bus, EIB) is shown, which unifies handling of the various physical media and bus access hardware available. Second, an approach with the goal of providing a generic representation of narrow-band building control functionality independent of a specific FAN technology is proposed. The interfaces are designed to be used by lightweight components of an OSGi (open services gateway initiative) platform, which is introduced as well.

A model based engineering tool for ROS component compositioning, configuration and generation of deployment information

Programming industrial robots requires experts -not only to create the robot applications, but also for changing them later due to different product requirements. Part of the reason for this is that all robot vendors provide their own robot programming language. Due to the language differences, robot applications cannot be reused for different robot types. Often, additional experts are required since one expert is trained only for a special robot type. This makes the use of robots uneconomical for small and medium sized enterprises. The ReApp project addresses this problem by providing a workbench based on ROS (Robot Operating System). A central part of this workbench is the skill and solution modeling tool, which allows the model-based design of robot applications composed of reusable components, and is described in this paper.