The Realization Of A HART-compliant Communication System In The Intelligent Radar Level Instrument

Radar Level instrument is a microwave measurement technology of high-precision non-contact level measurement instruments, currently widely used in petroleum, chemical and other industries. The existing radar-level usually only with analog signals or RS232 / 485 serial communication interface, it is difficult to adapt to the current level measurement automation system's development needs. HART communications protocol is a mixed communication protocol. It can make a presentation of information for the digital signal with a 4-20 mA analog control signals in one cable at the same time disseminating mutual influence. HART Protocol is characterized by the existing analog transmission, digital communications, taking into account the simulation system and the performance characteristics of digital systems, with strong competitiveness in the market.The thesis seeks to combine the advantages of the two, a design based on the radar HART bus-level communication module, making a radar-Level HART interface features, that based on HART the formation of large cans of industrial liquid level measurement Control network, improve the level measurement system automation management level.From the investigation of the market of Radar level instrument measurement system and performance requirements, the architecture of hardware and software of the HART transmitter is planned according to the required functions and performance of the Radar level instrument measurement system. In the hardware, a company introduced the use of Smar HT2021 modem, based on the use of the MCU protocol layer, a better balance between performance and system control manufacturing costs, increase system design flexibility and reliability. In the software, using C language assisted with assembly language programs the system's software. Assembly language is used to complete real-time control tasks, and C language can be used to construct the frame of software and complete those unreal-time control tasks, which can not only improve the efficiency of programming and the maintenance of the program, but also provide the system with good real-time performance.As the result, the developed prototypes of the HART-compliant communication system can wok with the anticipated functions and performance.