Siemens SIMATIC S5 Manual page 298

STEP 5 Programming
9.4 Sample Program 1: Overall Structure
For better readability, many subfunctions have been programmed in separate
FBs. The diagram below illustrates the overall structure:
OB 22
OB 1
Cyclic
operation
9-10
FB 27
Wait loop
FB 10
Mode 99
FB 26
Main
program
IP 266
FB 20
Read actual values
FB 4/Mode 4
For errors in the po-
sition control loop
FB 5/Mode 5
Traversing
FB 2/Mode 2
FB 6/Mode 6
FB 8/Mode 8
FB 9/Mode 9
FB 21/START
FB 23 FORWARD/
REVERSE
FB 24/TRANSFER
FB 22/STOP
FB 25/TOGGLE
EWA 4NEB 812 6057-02