基于USB总线接口的HART MODEM的研发与应用

The Development and Appliction of HART MODEM Module Based on USB Bus Interface

摘要:

现阶段工业自动化仪器仪表领域以HART总线为通讯的方式已经成为行业的标配,然而这种基于串行总线接口HART MODEM在工程实际的应用中存在实用性、便携性差和购买成本高的问题。为此,文章提出一种基于USB总线接口的HART MODEM模块的研发与应用,其目的是替换现有的基于串行总线接口的HART MODEM模块,同时解决现有模块所存在的问题。文中阐述的USB总线接口的HART MODEM模块以STC89C51RD微控制器为核心,通过USB驱动芯片CH375A接收PC机发来的HART协议帧,同时将协议帧通过DS8500 HART调制解调器芯片转发给工业现场HART型的总线仪表。经过实验与应用的验证,该模块的抗干扰性、通讯误码率均到达工业级产品指标,并广泛的应用于自动化仪器仪表中的压力变送器、温度变送器、流量计、执行器等领域。

Abstract:

At this stage HART bus communication has become the industry standard in the field of industrial automation instrument, but this HART MODEM which based on the USB bus interface has some problems in practical applications of the engineering,such as poor practicability, poor portability ,and high cost of purchase.Therefore, this paper puts forward a kind of research and application of HART MODEM module based on USB bus interface,its purpose is to replace the existing HART MODEM module which based on serial bus interface,at the same time solve the problems existing in the current module.In this paper the HART MODEM module based on USB bus interface uses the STC89C51RD microcontroller as the core,through the USB driver chip CH375A receiving the HART protocol frame which from PC,while the protocol frame is forwarded to the HART bus instrument in the industrial field by DS8500 HART modem chip. Through experiment and application verification,the noise immunity and communication bit error rate of the module reaches the industrial product index,and widely used in automation instrument ,such as pressure transmitter, temperature transmitter, flowmeter, actuator, and other fields.