扩切机是汽车车轮自动生产线的关键设备，本文探讨其可编程序控制器（ＰＣ）实现技术．根据扩切机要求复杂交互顺序控制的特点以及ＰＣ齐全的硬件和软件功能，具体研究了方案的硬件配置、软件编制及故障诊断和报警系统，并提出了两种复杂顺序控制系统的循环控制程序编制法──模块化结构程法和内部继电器循环控制法。实现的扩切机已由东风汽车公司运行三年，运行情况很好，经济效益显著。 Spreader is the key equipment of automobile wheel automatic production line. This article discusses its programmable logic controller (PC) technology. According to the characteristics of complex reciprocal sequential control required by expander and the complete hardware and software functions of PC, the hardware configuration, software compilation and fault diagnosis and alarm system of the program are studied in detail. And two kinds of cycle control programs of complex sequential control system Compilation - Modular construction method and internal relay cycle control method. The expansion machine has been run by the Dongfeng Motor Company for three years, running well, significant economic benefits.