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  Introduction to CTRL

A Control program ("script") is used to control WinCC OA, and can be programmed by the actual user of the control system. In this way the user is employing a script to specify the response of WinCC OA to an event. The syntax of the internal controller language "Control" has a similar structure to that of the C programming language.

The Control program is capable of multi-program operation (multi-threading). Blocks can be defined in the CTRL script that are processed when a specific event occurs ( for example, message that a data point attribute has changed). Since WinCC OA can process more than one data point at once, the Control program must also be capable of letting different processes run in parallel. The Control program must perform the following functions:

  • Control functions for technical processes

  • Enable dynamic handling of graphics objects

The Control program processes data points and controls the visualization of process states. The Control syntax is based on the procedural programming language C. Control, however, is implemented as an interpreter, so that the user does not have to perform compiling or linking. This means that changes can be tested immediately. Control provides optimum support for the flexible data point concept of WinCC OA.

IconNote

Only special characters from the iso88591 character set can be used in CTRL scripts. Special characters within variable names are not permitted.

Chapter

Description

Introduction to CTRL

Page with links and general introduction

Structure of CTRL scripts

How to structure a Control script

Execution modes

How the system executes scripts.

Addressing types

How to address data points and data point element

Data types

Possible data types in CTRL

Type conversions

Conversion of data types in CTRL

Variables and constants

Using variables and constants

Operators

Possible operators in CTRL

Control structures

Existing control structures (if-else etc.).

Control characters

Possible control characters

Comments

To mark comments

Wildcards

Using wildcards in scripts

Parameters

Parameter in CTRL.

Threads

How the system execute threads

Error handling

About error messages and how to interpret.

Multi-language capability

Data types and characteristics of Multi-language capability.

Control programming

Syntax of CTRL.

Control scripts

What are  CTRL scripts? Control scripts are programs written in the internal "Control" language, which is closely related to ANSI C. They are interpreted by the system and thus do not need compiling.

Control library

What are  CTRL libraries? A separate library can be created for Control scripts which can be accessed by all Control scripts in a project. This control library can also be changed at run time.

Loading Control libraries

Information on how to load a Control library.

CONTROL Code Coverage

Contents and usage of the Control Code Coverage.

Semantic Check of Scripts

Information on how to use the semantic check of scripts.

Predefined symbolical constants

Constants for operating system, directories and standard input/output.

 

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