HIMA EABT3 B9302 997009302 工业模块

HIMAEABT3 B9302 997009302  工业模块

指令系统:一个PLC所具有的指令的全体称为该PLC的指令系统。它包含看指令的多少，各指令都能干什么事，代表看PLC的功能和能。般讲，功能强、能好的PLC，其指令系统必然丰富，所能干的事也就多。我们在编程之前必须弄清PLC的指令系统

程序:PLC指令的有序集合，PLC运行它，可进行相应的工作，当然，这里的程序是指PLC的用户程序。用户程序一般由用户设计，PLC的广家或代销商不提供。用语句表达的程序不大直观，可读差，特别是较复杂的程序，难读，所以多数程序用梯形图表达。

梯形图:梯形图是通过连线把PLC指令的梯形图符号连接在一起的连通图，用以表达所使用的PLC指令及其前后顺序，它与电气原理图很相似。它的连线有两种:一为母线，另一为内部横竖线、内部横竖线把一个个梯形图符号指令连成一个指令组，这个指令组一般总是从装载(LD)指今开始，必要时再继以若于个输入指今(含LD指今)，以建立逻提条件。后为输出类指今，实现输出控制，或为数据控制，流程控制、通讯处理、工作等指令，以进行相应的工作，母线是用来连接指令组的。下图是三菱公司的FX2N系列产品的简单的梯形图例:

它有两组，组用以实现启动、停止控制。第二组仅一个END指令，用以结束程序

梯形图与助记符的对应关系:助记符指令与梯形图指令有严格的对应关系，而梯形图的连线又可把指令的顺序予以体现。一般讲，其顺序为:先输入，后输出(含其他处理);先上，后下，先左，后右。有了梯形图就可将其翻译成助记符程序。上图的助记符程序为:

HIMAEABT3 B9302 997009302  工业模块

Instruction system: All the instructions of a PLC are called the instruction system of the PLC. It includes looking at the number of instructions, what each instruction can do, representing the function and ability of the PLC. Generally speaking, the function is strong, can be good PLC, its instruction system must be rich, can do more. We must understand the instruction system of the PLC before programming

Program: The ordered set of PLC instructions, the PLC runs it, can carry out the corresponding work, of course, the program here refers to the PLC user program. The user program is generally designed by the user, and is not provided by the PLC's Guangji or affiliate. The program expressed in the sentence is not intuitive and readable, especially the more complex program is difficult to read, so most of the program is expressed by ladder diagram.

Ladder diagram: Ladder diagram is a connection diagram that connects the ladder diagram symbols of PLC instructions together through the connection to express the PLC instructions used and the sequence before and after, which is very similar to the electrical schematic diagram. Its connection has two kinds: one for the bus, the other for the internal horizontal and vertical lines, the internal horizontal and vertical lines to connect a ladder diagram symbol instructions into an instruction group, this instruction group generally always starts from the load (LD) refers to today, and then if necessary, if the input refers to today (including LD refers to today), to establish logic conditions. After the output class refers to this, to achieve output control, or for data control, process control, communication processing, work and other instructions to carry out the corresponding work, the bus is used to connect the instruction group. Here is a simple trapezoidal legend of Mitsubishi's FX2N series products:

It has two groups, which are used to implement start and stop control. The second set has only one END instruction, which ends the program

Ladder diagram and mnemonic correspondence: mnemonic instructions and ladder diagram instructions have a strict correspondence, and the ladder diagram line can also reflect the order of instructions. Generally speaking, the order is: first input, then output (including other processing); First up, then down, first left, then right. With the trapezoid diagram, it can be translated into a mnemonic program. The mnemonic program in the picture above is:

HIMAEABT3 B9302 997009302  工业模块