Enabling hardware-in-the-loop for building automation networks: A case study for BACnet and PowerDEVS

Hardware-in-the-Loop (HIL) is a well-established concept for developing and testing embedded systems. While it is widely used in industrial automation and the automotive area, it is rarely applied to Building Automation Systems (BAS). This work proposes the interconnection of a prominent building automation protocol, namely Building Automation and Control network (BACnet), and a simulator, PowerDEVS, to facilitate HIL testability of new and existing building automation networks. The Discrete Event Systems Specification formalism, used by PowerDEVS, is especially geared towards systems that show both discrete event and continuous state characteristics. Hence, the field of BAS is a prime candidate for such simulators. Further, the interconnection of HIL simulation and BAS via building automation networks allows for easy and location-independent testing of single field devices on one hand, and distributed BAS applications on the other hand. Therefore, design issues, and the pros and cons of a bridging solution between BAS and simulators are discussed throughout the course of this work. The paper introduces a modular software architecture for the interconnection of building automation networks and simulation. This allows for easy portability of the proposed design to other HIL simulators or building automation network protocols. The feasibility of the proposed approach is validated by means of a proof-of-concept.