BACnet Protocol's Implementation Based On The Embedded Linux

LonWorks and BACnet are two main technology and standard in building automation and control area. By supplying proprietary hardware and software tools, LonWorks makes its use very convenient. LonWorks makes its users rely on its hardware and software tools, so users can't develop the building automation and control products and systems with proprietary intellectual property rights. Though they can make profits from the market temporarily, they lose the key competitive strength in the far sight. Though there are many problems, if we can develop the building automation and control products and systems that have proprietary intellectual property rights with BACnet standard, we will win the key competitive strength.If a general BACnet embedded operating system can be developed and transplanted to many kinds of embedded system, then a system on chip similar to the LonWorks Neuron Chip can be developed. We can develop the building automation and control products with proprietary intellectual property rights conveniently, and break the dominance of the foreign products, and make our country's intelligent building market grow healthily.Linux is one of the mostly used operating systems in the embedded system area now. Its kernel is highly modular and configurable..It has strong abilities of task management, timer management, memory management, queue management and interrupt management. In this paper, a BACnet state machine has been implemented. Based on the kernel's timer management ability, the segment timer and the request timer have been achieved. Some basic services such as ReadProperty, WriteProperty have been implemented based on the state machine. Based on the kernel's queue management ability, the application service primitives have been implemented. Therefore , a basic BACnet communication platform has been developed. According to the different control requirements, different objects model can be made and then mapped to the different control hardware, then different controllers can be developed.In this paper, the BACnet embedded operating system is transplanted to a embedded system. The test result shows that the embedded operating system runs well and conforms to BACnet standard.