Step 5 Operations - Siemens CPU 948 Programming Manual

STEP 5 Programming Language
What is a block?
2.1.3

STEP 5 Operations

Example
2 - 6
Structured programming offers you the following advantages:
• • simple and clear creation of programs, even large ones
• • standardization of program parts
• • simple program organization
• • easy program changes
• • simple, section by section program test
• • simple system start-up
A block is a part of the user program that is distinguished by its
function, structure or application. You can differentiate between
blocks that contain statements (code) i.e. organization blocks,
program blocks, function blocks or sequence blocks, and blocks that
contain data (data blocks).
A STEP 5 operation is the smallest independent unit of the user program.
It is the work specification for the CPU. A STEP 5 operation consists of
an operation and an operand as shown in the following example:
Operation code
:O F 54.1
Operation
(what is to be done?) (with what is the
Parameter
Operand
operation to be done?)
CPU 948 Programming Guide
C79000-G8576-C848-04