Rockwell Automation 1785-LTx,D17856.2.1 Classic PLC-5 Programmable Controllers Users Manual - Manual (Page 72)

Chapter
6
6-1
Planning Your System Programs
This chapter covers basic programming considerations for planning a
Classic PLC-5 programmable controller system.
If you want to read about: Go to
page:
Planning application programs 6Ć1
Using SFCs 6Ć1
Preparing programs for
your application
6Ć3
Addressing the data table 6Ć7
Using the processor status file 6Ć9
See your programming software documentation for a discussion of the
instructions used in ladder-logic programming.
Use the functional specification that you previously developed to define
your programming application. The specification is a conceptual view of
your application and is used to determine your main program, sequential
function chart (SFC), and logic requirements.
In planning and developing the programs for your application, we
recommend that you use the program-development model shown in
chapter 1, “Understanding Your System.”
Use SFCs as a sequence-control language by which you can control and
display the state of a control process. Instead of one long program for
your application, divide the logic into steps and transitions. The display of
these steps and transitions lets the user see what state the machine process
is in at a given time.
Chapter Objectives
Planning Application
Programs
Using SFCs with
PLCĆ5 Processors
System Design
Determined
Choosing
Communication
Transferring Discrete
and Block Data
Planning Your
System Programs
Calculating Program
Timing
Choosing Hardware
Placing System
Hardware
Assigning Addressing
Mode, Racks,
and Groups
Selecting Interrupt
Routines