四、程序的编写和输入有了完整的工艺控制梯形图,编写程序就比较简单容易。只要正确地选用有关PC指令依次将梯形图中所有的回路加于描述,最后加一条结束指令即可。梯形图中,每个回路在编程结构上占有一个相对独立的程序段。对初学者来说,一般只要求严格按梯形图编写,便于检查和修改;对熟练的编程人员还需要考虑尽可能地节省内存空间和提高程序的执行效率,他 Fourth, the preparation and input procedures With a complete process control ladder, the preparation of the program is relatively simple and easy. As long as the correct choice of the relevant PC instructions in turn all the ladder diagram added to the description, and finally add an end instruction. Ladder diagram, each circuit occupies a relatively independent program segment in the programming structure. For beginners, generally only requires strict preparation according to the ladder diagram, easy to check and modify; for skilled programmers also need to consider saving memory space as much as possible and improve the efficiency of the program, he