Design of communication system in intelligent instrument based on HART protocol

At present, fieldbus has already become the hot spot in process control filed, on Behalf of the necessary trend in the development of process instrument. As the International Standard of fieldbus accomplished, the fieldbus product is surely accepted by the market for its consummate function and extrusive characteristics. Because HART realizes digital communication in the transmission of analog signals. In this paper, the design of communication module in intelligent instrument based on HART protocol is a useful attempt of HART Protocol on application of intelligent instruments. Based on the needs of the practical environment, author proposes an idea of “modularization”. For that, this design can be extensively used, and the existent products can be upgraded easily by small changes. In this paper, the design of hardware and software for HART protocol communication system was introduced and analyzed. In the aspect of hardware it introduced the system of chip selection and circuit design and in part of software the structure of system was detailed analysis and description and this paper gives some further introduction and discuss about how to realize the anti-interference of HART protocol software. In addition, the device debugging and test function is introduced at the end of this paper.