TABLE OF CONTENTS Producing a programming station that provides all the software management, the graphical and textual editors, the build system and run-time diagnostics required for programming IEC 1131-3 based PLCs is a major software development undertaking.
In this chapter we will review the many aspects of an IEC 1131-3 programming station, particularly:
Requirements for an intuitive user interface;
Support for hierarchical design decomposition;
Library management for re-usable software elements;
Built-in program consistency checks;
Provisions for selecting different programming languages;
On-line diagnostics.
Any programming system for control applications based on IEC 1131-3 requires a wide range of features to ensure that programs can be readily developed and maintained by control engineers using a user friendly and robust development environment.
We have seen that IEC 1131-3 style control programs are developed using a top-down design approach where programs generally consist of a hierarchy of graphical diagrams and textual definitions. A programming system should therefore offer facilities that encourage engineers to exploit the benefits of well structured top-down program design.
The main function of a programming system is to provide control engineers and system programmers with facilities to translate their program concepts into a structured and validated set of program diagrams and definitions for which run-time, executable programs can be rapidly created.
Apart from an understanding of the control system languages, engineers using such a programming system should not require any particular or specialist computer skills. Full use should be made of windows style graphical user interface and...
