Technical data

Basics of Designing a Program Structure
4.2 Blocks in the User Program
Programming with STEP 7
Manual, 05/2010, A5E02789666-01 79
Linear Versus Structured Programming
You can write your entire user program in OB1 (linear programming). This is only advisable with
simple programs written for the S7-300 CPU and requiring little memory.
Complex automation tasks can be controlled more easily by dividing them into smaller tasks
reflecting the technological functions of the process or that can be used more than once. These
tasks are represented by corresponding program sections, known as the blocks (structured
programming).