Design Of Current Analog Output And Redundant Dcs Interface Based On Hart Protocol

DCS (Distributed Control System) has been used in modern industrial field for many years. In recent years, although DCS has been challenged by many other systems, it must be existent and developing in a long time because of the wide application in future market and the effort to meeting the new demands. Field bus is a quick developing industrial data bus which is used in industrial field to solve the digital communication in intelligent instrumentation, controllers and actuators, and is also used to deal with the message between Field Control Equipment and Advanced Control System.HART Communication Protocol is widely accepted as digital extended communication protocol established on 4-20mA in industrial control area and gradually becoming a standard in intelligent instrument industry actually. As the wide application in future and huge market requirement, many countries and groups are committed to HART protocol research, which made a wide range and an accessorial quantity of this kind of product. Distinguished from other digital communication protocol, HART Protocol retains the original 4-20mA system. This mechanism provides a backward-compatible upgrade program for users to savings when they upgrade their system. Smart Device with HART Communication capabilities can enhance the overall information management capabilities without extra capital investment. So in many aspects, HART Protocol has stronger competitiveness than the other protocol in market. High reliability is the foremost request in process control system, and redundancy technology is widely used in computer system to effectively improve the reliability of the system. For the purpose of high reliability and low failure rate, we usually use appropriate redundancy technology in the design and application of the system.We first recommend the HART Protocol briefly, then emphasize the standards of each layer, while we also analysis the redundancy technology at bottom-interface of DCS System. After that, we detail the principle of modules in hardware and software in the article. At last, we list the module performance parameters and test results in the appendix to show the product.