Design The Protocol Conversion Module Between The HBS Protocol And BACnet

Intelligent building is the main development direction of the construction industry in this century,.It is one of the specific manifestation of our ecological civilization sustainable development strategy in the construction industry, and building automation is the most essential elements in the intelligent building. Over the years, developers, builders and engineers have been plagued by the integration and application of building automation system. It is difficult to integrate various subsystem with different manufacturer’s product,due to diversified system field bus technologies and communication protocols.A Fieldbus technology is a type of digital communication technology, that realize the two-way, serial or multi-node communication between different devices and associated devices,and between devices and control system in the field. At present, the Fieldbus has been applied in the control system design process of the engineering work and other system.The combination of automatic control and network control mode is gradually replacing the old distribution control and the use of computer hierarchical control mode. The multiple field bus technology used in the project site of late,together with multiple differences in varipus,protocol standards complicate application; this situation also affected the field bus-compatibility and openness, and increased the system’s difficulty to achieve mutual communication. So it is essential to requires various protocol conversion devices to interconnect different forms of the Fieldbus in the project site.According to the current situation, this paper first summarizes the concept and characteristics of the Fieldbus, introduces the featuers of several common Fieldbus technology in BMS, and then establish the main goal of this paper to study and design a new protocol conversion module between the HBS protocol and BACnet. Furthermore, it explains the OSI seven layer protocol system structure, and the structure and the function of BACnet.Then,by using MITSUMIELECTRIC company’s MM1192chip for the HBS communication, and by using DB83848to realize the Ethernet communication in building automation system, the author designs and develops a protocol conversion module based on the Renesas H8/3687and NXP LPC1768(ARM Cortex-M3), to solve the problem of the different Fieldbus form and communication protocols between building automation system and central air-conditioning systems; and then set up the appropriate external circuit to achieve the exchange of data between two systems.Based on this hardware circuit, the author designs and completes each functional module’s control procedures and communication procedures, to enable protocol conversion module to successfully complete the exchange of data between the building automation system and central air conditioning system. The protocol conversion module communicates with host computer via the building automation system’s BACnet protocol, and with extension machine via the H-Link communication protocol of the central air conditioning system. In practical applications, protocol conversion module is able to send the following information to the building automation system, such as start and stop of the central air conditioning system, running mode, wind speed, wind direction, set temperature, return air temperature and the alarm code, so that managers can keep track of each user’s the air conditioning system status, and use the automatic control system to set the user’s air-conditioning systems’commands including start and stop, wind speed, wind direction and temperature..., This realizes the connection of the building automation systems and commercial central air conditioning system. One can monitor the environment of the users and the state of the air-conditioning, to control the air conditioner’s (the Energy consumption facility of the buildings) running status, so as to achieve energy saving and environmental protection requirements.More and more attention has been paid to the Fieldbus techonoly these days, especially the openness and compatibility of the field bus.The design of the protocol conversion module in the paper is a new development in this field, and is still running the experimental stage.However it laid the foundation for further study of the interconnection between the communication protocol conversion, thus has a certain practical significance. The design also laid the foundation for the similar protocol conversion module to be applied in more industrial field in the future.