| As various kinds of technology including Computer, Communication, Control and Cathode Ray Tube(CRT) developing quickly, Measurement & Control Network(MCN) tends towards networking, distributing, opening and interoperating, which is widely applied in many fields such as industry automation, Intelligent Building, processing control, etc.Firstly, this paper makes a detailed study on the prevalent Field Control Systems(FCS), including the characteristics of structure & technology and advantage, introduces several popular Field Buses, designs the model of field control system, and puts forward three effective methods to integrate between the MCN & information network under different situations. Secondly, it lucubrates the LonWorks and BACnet which are widely applied in the control network of the intelligent building, educes three schemes of integration to control networks in the intelligent building due to the different characteristics of them and the products in intelligent building system. Thirdly, a system, based on RS-232 and RS-485 for centralized mass to realize on-line reading record, is designed. The paper makes up techno-requirement and communication protocol, and describes the design for hardware and software of the system. Many safeguards are taken to ensure the reliability and stability of the system. Finally, in order to utilize the power lines to transmit the digital signals well, an On-line Reading Record System with the Neuron chip of LonWorks as core is developed, which communicates by power lines in use of power line transceiver. Several schemes are advanced for security: random data confirm the sequence of data, Hash arithmetic operates the data, and one-off encryption encrypts the Hash value & random data. Furthermore, soft-relay is employed to reduce the coupling of the three-phase voltages and prolong the distance of communication, which intensifies the capability via price, reliability and stability of the system. |
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