Design And Research Of Lonworks Network Control Node Based On The Multiprocessor Structure

With the development of the information technology, the fieldbus technology is widely applied in the industrial automation and BA(building automation). In BA, as one kind of the fieldbus, LonWorks technology becomes a leading control network, because of its outstanding characteristics such as:interoperability, openness and powerful distributed processing capability.In the LonWorks control network those network control nodes, based on Neuron 3150 chip, are usually used to manage the numerous control devices in the buildings, but as it is known, the processing capability of Neuron 3150 chip is so weak that it is unable to satisfy those requirements in a complex and diverse application environment. This is resulting in a new problem:How to make use of the control ability of the network control node under the precondition of taking advantage of the powerful communication ability of the Neuron 3150 chip. In order to address the question, a multiprocessor-basedly LonWorks network control is designed using the powerful control ability of the host-processor to offset the poor controlling performance of Neuron 3150 chip, at the same time, the LonWorks communication ability of the Neuron 3150 chip is exploited to integrate the designed network control node into the LonWorks control network.As for hardware design of the multiprocessor-based LonWorks, ATmegal28 chip works as the host-processor. Based on the rich internal resources and programmable I/O(Input/Output) ports provided by ATmegal28, the external control electric circuit has been designed. The assistant-processor is a Lon control module with a Neuron 3150 chip inside which integrates the network control node into the LonWorks control network. In the aspect of the software design, some commonly used control modules, such as: human-machine interaction platform, data storage and safety certification module, data communication module, are implemented using module oriented programming method. A proposed improvement in the part of the communication module includes the dual-port RAM(Random Access Memory) communication technology which exchange data between the host-processor and assistant-processor in order to effectively solve the data transmission problem resulted from the asynchronous clock.In this thesis, the superiority of the multiprocessor-based LonWorks network control node is verified when experimentally compared with the LonWorks network control node based on Neuron 3150 chip in terms of the hardware design, the software design as well as practical applications. Results from a project experiment conducted in the solid garage intelligent control system prove its feasibility.