基于J1939协议的重型车OBD诊断仪软件设计

Software Design of Heavy-duty Vehicle OBD Scanner Based on J1939 Protocol

J1939协议是国标规定的柴油车的OBD协议,外部诊断设备要与车辆通信,必须满足J1939协议的要求。文章对一种基于J1939协议的诊断仪的软件设计进行了说明。分析了J1939协议报文的特点,对请求报文的发送,广播报文的接收,多帧报文的传输协议,故障码的解析等进行了实例说明,并设计了整个程序处理流程。实际使用中能正确读取车辆数据,实时性好。

J1939 protocol is the OBD protocol of diesel vehicle stipulated by the national standard.If the external diagnostic equipment wants to communicate with the vehicle,it must meet the requirements of J1939 protocol.In this paper,I described the software design of an OBD scanner based on J1939 protocol.I analyzed the characteristics of J1939 protocol message,illustrated the sending of request message,the receiving of broadcast message,the transmission protocol of multi-frame messages,the analysis of DTC,and designed the whole program processing flow.In practice,it can read the vehicle data correctly and has a good real-time performance.