ABB ST语言编程(3)

System 800xA Training

13.2Structured Text

Structured Text (ST) is a high-level programming language. It is compact, highlystructured and contains a comprehensive range of constructs for assignments,

function/function block calls, expressions, conditional statements, iterations and more.The code is simple to write and easy to read, because of its logical and structuredlayout. The compactness of the language gives an excellent overview of the code andless scrolling in the editor.

13.2.1Advantages of Using Structured Text

1.Free layout of code and comments

2.When in online mode the layout can be changed to Function Block or Ladder for

viewing by different personnel.

3.Text may be generated in any external text editor and pasted into the ST editor.

For example you might use macros in MS Word to generate code.

4.Structured text reads like English and is the most efficient way of writing code.

5.You will have to learn Structured Text in any case because it is the only choice in

the SFC editor!

A small example of code written in Structured Text is shown below:

Chapter13-3