首页 > 其他分享 >[水一篇] Structured Text(ST)

[水一篇] Structured Text(ST)

时间:2024-10-30 21:59:37浏览次数:1  
标签:WORD Text Structured ST Output VAR END supports

Structured Text (ST), a programming language used in
Programmable Logic Controllers (PLCs).

Structured Text is a high-level language that's widely used in industrial
automation and control systems. It's a text-based language that allows
programmers to write logic and control code for PLCs, which are used in
various industries such as manufacturing, oil and gas, water treatment,
and more.

ST is known for its ease of use, flexibility, and readability, making it a
popular choice among PLC programmers.

What is Structured Text (ST)?

Structured Text (ST) is a high-level programming language used to program
Programmable Logic Controllers (PLCs). It's a text-based language that
allows you to write logic and control code for PLCs.

Key Features of ST:

  1. Easy to Read: ST code is written in plain English, making it easy
    to understand and maintain.
  2. High-Level Language: ST is a high-level language, meaning it
    abstracts away from the low-level details of the hardware, allowing you to
    focus on the logic of your program.
  3. Platform Independent: ST code can be run on any PLC that supports
    the language, regardless of the manufacturer or model.

Basic Syntax:

Here's a simple example of an ST program:

PROGRAM Example
VAR
  Input : BOOL;
END_VAR

IF Input THEN
  Output := TRUE;
ELSE
  Output := FALSE;
END_IF

Let me explain what each part does:

  • PROGRAM is the keyword that starts a new program.
  • Example is the name of our program.
  • VAR declares variables, which are stored values used in our program.
    In this case, we have two variables: Input and Output.
  • The IF statement checks a condition (in this case, whether Input is
    TRUE or FALSE).
  • If the condition is true, then the code inside the THEN block is
    executed.
  • If the condition is false, then the code inside the ELSE block is
    executed.

Basic Data Types:

ST uses various data types to store values. Here are some common ones:

  1. BOOL: A boolean value that can be TRUE or FALSE.
  2. WORD: A 16-bit unsigned integer value.
  3. DWORD: A 32-bit unsigned integer value.
  4. REAL: A floating-point number with a maximum of 8 decimal places.

Control Statements:

ST supports various control statements, such as:

  1. IF-THEN-ELSE: Used to execute different code based on conditions.
  2. FOR: Used for looping through a range of values.
  3. WHILE: Used for looping until a condition is met.
  4. CASE: Used for executing different code based on the value of an
    expression.

That's a basic introduction to Structured Text (ST) and its syntax! Do you
have any specific questions or topics you'd like me to cover next?

teach me more
Let's dive deeper into Structured Text (ST) programming.

Variables and Data Types

In ST, variables are declared using the VAR keyword. Here are some
examples:

VAR
  Input : BOOL;  // boolean variable
  Counter : WORD := 0;  // 16-bit unsigned integer variable with initial 
value 0
  Temperature : REAL := 20.5;  // floating-point number variable with 
initial value 20.5
END_VAR

ST supports various data types, including:

  1. BOOL: A boolean value that can be TRUE or FALSE.
  2. WORD: A 16-bit unsigned integer value (0-65535).
  3. DWORD: A 32-bit unsigned integer value (0-4294967295).
  4. REAL: A floating-point number with a maximum of 8 decimal places
    (-3.40E38 to 3.40E38).
  5. TIME: A time value in hours, minutes, and seconds.

Operators

ST supports various operators for performing arithmetic, comparison,
logical, and assignment operations:

  1. Arithmetic Operators:
    • + (addition)
    • - (subtraction)
    • * (multiplication)
    • / (division)
    • MOD (modulo operation)
  2. Comparison Operators:
    • = (equal to)
    • <> (not equal to)
    • < (less than)
    • > (greater than)
    • <= (less than or equal to)
    • >= (greater than or equal to)
  3. Logical Operators:
    • AND (logical AND)
    • OR (logical OR)
    • NOT (logical NOT)

Control Statements

ST supports various control statements for executing different code:

  1. IF-THEN-ELSE:
IF Input THEN
  Output := TRUE;
ELSE
  Output := FALSE;
END_IF
  1. FOR:
FOR Counter := 0 TO 10 DO
  LED := TRUE;
END_FOR
  1. WHILE:
VAR
  Counter : WORD := 0;
END_VAR

WHILE Counter < 5 DO
  LED := TRUE;
  Counter := Counter + 1;
END_WHILE
  1. CASE:
CASE Input OF
  FALSE:
    Output := FALSE;
  TRUE:
    Output := TRUE;
END_CASE

Functions
ST supports user-defined functions for reusing code:

FUNCTION Add(a : WORD; b : WORD) : WORD
VAR
  Result : WORD;
END_VAR

Result := a + b;
RETURN Result;
END_FUNCTION

You can call the Add function using:

Output := Add(10, 20);

Arrays and Structures

ST supports arrays and structures for storing multiple values:

  1. Arrays:
VAR
  Array : ARRAY[0..9] OF WORD;
END_VAR

Array[5] := 50;
  1. Structures:
TYPE
  Point : STRUCT
    X : WORD;
    Y : WORD;
  END_STRUCT
END_TYPE

Point.X := 10;
Point.Y := 20;

These are some of the basic features and constructs in Structured Text
(ST). Do you have any specific questions or topics you'd like me to cover
next?

Loops

ST supports various types of loops for executing code repeatedly:

  1. FOR Loops:
FOR i := 0 TO 9 DO
  Output[i] := TRUE;
END_FOR
  1. WHILE Loops:
VAR
  i : WORD := 0;
END_VAR

WHILE i < 10 DO
  Output[i] := TRUE;
  i := i + 1;
END_WHILE
  1. DO-UNTIL Loops:
VAR
  i : WORD := 0;
END_VAR

DO
  Output[i] := TRUE;
  i := i + 1;
UNTIL i >= 10

Arrays

ST supports arrays for storing multiple values:

TYPE
  MyArray : ARRAY[0..9] OF WORD;
END_TYPE

You can initialize an array using:

MyArray := [0, 20, 30, 40, 50, 60, 70, 80, 90, 100];

Or you can access individual elements of the array using:

Output := MyArray[5];  // Output will be 50

Structures

ST supports structures for storing multiple values:

TYPE
  Point : STRUCT
    X : WORD;
    Y : WORD;
  END_STRUCT
END_TYPE

MyPoint : POINT;

You can initialize a structure using:

MyPoint := [X:=10, Y:=20];

Or you can access individual elements of the structure using:

Output := MyPoint.X;  // Output will be 10

Records

ST supports records for storing multiple values:

TYPE
  Point : RECORD
    X : WORD;
    Y : WORD;
  END_RECORD
END_TYPE

MyPoint : POINT;

You can initialize a record using:

MyPoint := [X:=10, Y:=20];

Or you can access individual elements of the record using:

Output := MyPoint.X;  // Output will be 10

Functions

ST supports user-defined functions for reusing code:

FUNCTION Add(a : WORD; b : WORD) : WORD
VAR
  Result : WORD;
END_VAR

Result := a + b;
RETURN Result;
END_FUNCTION

You can call the Add function using:

Output := Add(10, 20);  // Output will be 30

Subroutines

ST supports subroutines for executing code:

SUBROUTINE MySub
VAR
  i : WORD;
END_VAR

FOR i := 0 TO 9 DO
  Output[i] := TRUE;
END_FOR
END_SUBROUTINE

You can call the MySub subroutine using:

MySub();

Type Definitions

ST supports type definitions for creating new data types:

TYPE
  MyType : TYPE DEFINITION OF WORD;
END_TYPE

You can use the MyType type in your code like any other built-in type.

Library Functions

ST supports library functions for accessing pre-defined functions and
variables:

VAR
  i : WORD := Lib_Add(10, 20);
END_VAR

You can use library functions to access pre-defined functions and
variables.
Object-Oriented Programming

ST supports object-oriented programming (OOP) concepts such as classes,
objects, inheritance, and polymorphism:

  1. Classes:
CLASS MyClass
VAR
  X : WORD;
END_VAR

CONSTRUCTOR MyClass
VAR
  i : WORD := 0;
END_VAR

X := i;
END_CONSTRUCTOR
  1. Objects:
VAR
  myObject : MyClass;
END_VAR

myObject := new();
  1. Inheritance:
CLASS MySubClass : MyClass
VAR
  Y : WORD;
END_VAR

CONSTRUCTOR MySubClass
VAR
  i : WORD := 0;
END_VAR

Y := i;
END_CONSTRUCTOR
  1. Polymorphism:
FUNCTION MyFunction(obj : OBJECT)
VAR
  result : WORD;
END_VAR

CASE obj OF
  MyClass :
    result := MySubClass.X;
  MySubClass :
    result := MySubClass.Y;
END_CASE

RETURN result;
END_FUNCTION

Event-Driven Programming

ST supports event-driven programming (EDP) concepts such as events,
handlers, and publishers:

  1. Events:
EVENT MyEvent
VAR
  data : WORD;
END_VAR
  1. Handlers:
ON_EVENT(MyEvent)
VAR
  i : WORD := 0;
END_VAR

data := i;
END_ON_EVENT
  1. Publishers:
PUBLISH(MyEvent, 10);

Graphical User Interface

ST supports graphical user interface (GUI) programming concepts such as
windows, buttons, labels, and text boxes:

  1. Windows:
WINDOW MyWindow
VAR
  width : WORD := 400;
END_VAR

CREATE(MyWindow, width, 300);
  1. Buttons:
BUTTON MyButton
VAR
  text : STRING := "Click me!";
END_VAR

CREATE(MyButton, 100, 50);
  1. Labels:
LABEL MyLabel
VAR
  text : STRING := "Hello, world!";
END_VAR

CREATE(MyLabel, 150, 20);
  1. Text boxes:
TEXT_BOX MyTextBox
VAR
  width : WORD := 200;
END_VAR

CREATE(MyTextBox, width, 50);

**Networking^[[200~```st
TYPE
Point : RECORD
X : WORD;
Y : WORD;
END_RECORD
END_TYPE

MyPoint : POINT;

You can initialize a record using:
```st
MyPoint := [X:=10, Y:=20];

Or you can access individual elements of the record using:

Output := MyPoint.X;  // Output will be 10

Functions

ST supports user-defined functions for reusing code:
^[[201~**

ST supports networking programming concepts such as sockets, clients, and
servers:

  1. Sockets:
SOCKET MySocket
VAR
  port : WORD := 8080;
END_VAR

CREATE(MySocket, port);
  1. Clients:
CLIENT MyClient
VAR
  server : STRING := "localhost";
END_VAR

CONNECT(MyClient, server, 8080);
  1. Servers:
SERVER MyServer
VAR
  port : WORD := 8080;
END_VAR

LISTEN(MyServer, port);

Database

ST supports database programming concepts such as connections, queries,
and transactions:

  1. Connections:
DATABASE MyDatabase
VAR
  host : STRING := "localhost";
END_VAR

CONNECT(MyDatabase, host);
  1. Queries:
QUERY MyQuery
VAR
  query : STRING := "SELECT * FROM users;";
END_VAR

EXECUTE(MyQuery, query);
  1. Transactions:
TRANSACTION MyTransaction
VAR
  transaction : BOOL := TRUE;
END_VAR
BEGIN(MyTransaction);
...
COMMIT(MyTransaction);

上述内容由本地大语言模型llama3.2生成===

标签:WORD,Text,Structured,ST,Output,VAR,END,supports
From: https://www.cnblogs.com/PrepAndPonder/p/18516692

相关文章

  • 把代码绑定到WPF中的textblock中
    在WPF中,将数据绑定到TextBlock控件中是一个常见的操作,这样可以动态显示数据源中的数据。以下是如何将数据绑定到TextBlock的步骤:定义数据源:首先,你需要有一个数据源,它可以是一个属性,这个属性需要实现INotifyPropertyChanged接口以便在数据变化时通知UI更新。设置DataContex......
  • Docker 自建 Registry
    如果你需要保存自己的镜像,但又不想直接公开出来,那么可以选择自建Registry.如果想要加速国内访问,可以选择自建DockerProxy,或者使用https://dockerproxy.net.本文发表于https://clouder0.com/zh-cn/posts/docker-registry-self-host/.需要把我自己打包的image部署出来,自......
  • rust中map和set的基本使用
    1.HahsMaphttps://rustwiki.org/zh-CN/std/collections/struct.HashMap.html跟着文档,查看一下hashmap的方法,调试,输出一下,就能学会使用了。usestd::collections::HashMap;usestd::any::type_name;//输出变量类型fnprint_type_of<T>(_:&T){println!("{}",type_name......
  • STM32学习笔记-GPIO
    参考江科大32单片机学习相关知识GPIO基本构造APB2(AdvancedPeripheralBus2)是STM32微控制器架构中的一个外设总线,用于连接一些高性能外设,如定时器、USART、ADC和GPIO等。这些外设通常对性能要求较高,需要更快的数据传输速率。相较于APB1,总线频率更高,适合用于需要快速响应......
  • 基于STL的自定义栈与队列实现:灵活选择底层容器的模板设计
    文章目录代码模板设计主要成员函数底层容器的选择模板设计底层容器的选择关于stack的示例代码关于queue的示例代码前言:在本文中,我们将分析一个模拟C++标准模板库(STL)栈的自定义实现以及模仿C++标准模板库(STL)队列的自定义实现。该stack类模板允许在底层容器的选择......
  • 2024最新Instagram养号攻略!海外社媒起号码住了
    Instagram至今仍然是全球顶级的流量平合,不仅在国外是各大网红明星必备app,国内下载量也居高不下,但从2018年下半年开始加大了对新账号的监控和权限限制。新注册的账号会受到诸多限制,稍不慎就会进入安全模式或者被封,所以如果你正打算为企业或个人运营Instagram账号,做好养号成了必......
  • 【红队】利用 PsycheShell 进行 Paste Jacking 以获取隐秘的反向 Shell
    原创Ots安全介绍在网络安全领域,粘贴劫持(PasteJacking)等技术代表着社会工程攻击日益复杂的趋势。当用户从网页上复制看似无害的内容,但粘贴的内容却遭到恶意篡改时,就会发生粘贴劫持。攻击者可以使用此技术在目标机器上执行命令,尤其是当用户粘贴到终端等敏感环境中时。在本......
  • Statistics and Data Analysis for Bioinformatics
    StatisticsandDataAnalysisforBioinformaticsAssessmentInformationSummativeAssessmentThecoursewillbeassessedbyin-courseassessmentconsistingof2components:aMCQquiz(20%)andaclassreport(80%).MCQtest(20%)22/10/2024Themultiplech......
  • Question Decomposition Improves the Faithfulness of Model-Generated Reasoning
    文章目录题目摘要简介结果相关工作结论附录题目问题分解提高了模型生成推理的准确性论文地址:https://arxiv.org/abs/2307.11768摘要    随着大型语言模型(LLM)执行越来越困难的任务,验证其行为的正确性和安全性变得越来越困难。解决此问题的一种方法是促......
  • 华为OD机试 E卷 2024|增强的strstr(Python)
    0、关于本专栏&刷题交流群本文收录于专栏【2024华为OD机试真题】,专栏共有上千道OD机试真题,包含详细解答思路、与四种代码实现(Python、Java、C++、JavaScript)。点击文末链接加入【华为OD机试交流qun】,和群友一起刷题备考。刷的越多,考试中遇到原题的概率就越大,永久、实时......