Dadla Ponizil


Workforce Development September 1, 2001

The Essentials of Structured PLC: the tutorial

Figure 1 L adder code, as any other software language, can--and should--follow principles of structured programming: modularity, top down design, single entry/exit points, bottom up testing. This tutorial will provide the essentials to do just that: develop PLC code that can be read and supported once the project is signed off. This methodology is called Station Mapped Programming (SMP) and the four steps are described on the following pages. Step 1: Divide and Conquer: Separate the project into its sub-systems. Unless a system is so basic (fewer than say 16 I/O) it can be segregated into modules or sub-tasks.

By Dadla Ponizil