The Research And Development Of HART Protocol Based Signal Collecting/alarming System

This project is supported by ChangZhou ShanLin Automatization Co., based on the industry field protocol -Highway Addressable Remote Transducer(HART). The main purpose of the project is to perform HART oriented signal collecting, monitoring, processing and alarming. The key aspect of our project is to develop a highly effective HART Interface Module (HIM). We fully customized HIM to the meet the specific requirement of its application. Moreover, we also emphasize its cost effectiveness by carefully selecting center processing unit and HART modems. This leads to further reduction of the HIM system cost while system usability guaranteed.We have successfully implemented all major functions required for HART compatibility during the development. In HART demodulation circuitry, we used delay-compare loop in waveform converting. This method is especially simple and easy to implement. Furthermore, it fully capable of tracking digital control signals carried by 4~20mA analog signals; During software development phase, we have completed signal collecting, LCD displaying, D/A converting of HART signal and IEEE-754 32 bit float point conversion. We used a simplified method in IEEE-754 32 bit compatible float point conversion based on the 24 bit integer and 16 bit decimal computation. This system implemented a fully compatible HIM function, which can be used for signal collecting and monitoring and are suitable for a wide variety of applications.Further improvements are possible via HIM field testing, and system integration.