目录引 言························································································4第一章 概述·················································································51
1 数控系统的简介····················································································51
1 数控系统发展简史及趋势······································································51
2 数控(NC)阶段·················································································51
3 计算机数控(CNC)阶段······································································51
2 PLC 简介····························································································61
1 PLC 定义···························································································61
2PLC 的结构与组成···························