“电气控制与PLC”课程中疑难指令的教学探讨

摘要

This paper has thoroughly analyzed the difficult topics in teaching Omron CPM1A series PLC.Topics related to TR,differential and anti-differential instruction forms,and step transition conditions for sequence control are considered to be difficult portions.The paper also utilizes ladder diagrams and examples to illustrate TR function,meaning behind the differential and anti-differential instruction forms.It explicitly explains the action of previous step control bit among step transition conditions in sequence control,and highlights the easily-ignored problems in common LD N command.The result is beneficial and applicable in easing the teaching difficulties,improving teaching efficiency on PLC subject.%本文针对欧姆龙CPM1A系列PLC的TR、微分与非微分指令形式、顺序控制步转换条件等教学难点进行了深入剖析。结合梯形图实例讨论了TR作用、指令的微分与非微分形式的意义、顺序控制步转换条件中上步控制位的作用及常用指令LD N容易忽视的问题。所作分析有益于克服PLC教学难点,提升教学效果。