Introduction.

5.Program structures
INTRODUCTION: 1
5.1 CYCLIC ORGANIZATION BLOCK (COB 0 TO 15) 1
5.2 PROGRAM BLOCKS (PB 0 TO 299) 3
5.3 FUNCTION BLOCKS ( FB 0 TO 999 ) 5
5.4 STRUCTURE VIEW AND EXECUTION PATH 6
5.5 EXCEPTION BLOCK (XOB) 7
5.6 SEQUENTIAL BLOCKS (SB 0 TO 31) 10
Introduction:
The key to fast programs, lies in the structure of a program. The structure is the
most important part of your entire project, because it makes your program readable
to others, makes it portable, easier to extend and to maintain. Before you start to
write your program you need to have an idea about all the different tasks your installation
will have to solve. PG5 organizes the program parts in different kinds of
blocks, each with it's special function:
There are five different types of blocks:
CB's ( Cyclic Organization Blocks)
FB's ( Function Blocks )
PB's ( Program Blocks )
XOB's ( Exception Blocks )
SB's ( Sequential Blocks ) called Graftec