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.

Note

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.

V 3.11 SP1