Siemens CPU 948 User Manual

2.2 Program, Organization and Sequence Blocks
Program blocks (PBs), organization blocks (OBs) and sequence
blocks (SBs) are the same with respect to programming and calling.
You can program all three types in the LAD, CSF and STL methods
of representation.
Programming When programming organization, program and sequence blocks,
proceed as follows:
Step Action
1 First indicate the type of block and then the number of the
block that you want to program.
The following numbers are available for the type of
block listed:
- program blocks 0 to 255
- sequence blocks 0 to 255
- organization blocks 1 to 39
2 Enter your program in the STEP 5 programming language.
When programming PBs, OBs and SBs, you can only
use the STEP 5 basic operations!
A STEP 5 block should always be a self-contained
program section.
Logic operations must always be completed
within a block.
3 Complete your program input with the block end
operation "BE".
Block calls With the exception of OB 1 to OB 39 you must call the blocks to
process them. Use the special STEP 5 block call operations to call the
blocks.
You can program block calls inside an organization, program,
function or sequence block. They can be compared with jumps to a
subroutine. Each jump causes a block change. The return address
within the calling block is buffered by the system.
Program, Organization and Sequence Blocks
CPU 948 Programming Guide
2 - 16 C79000-G8576-C848-04

Siemens CPU 948 Specifications

General

Brand	Siemens
Model	CPU 948
Category	Controller
Language	English