Rockwell Automation 1785-LTx,D17856.2.1 Classic PLC-5 Programmable Controllers Users Manual - Manual (Page 13)

Understanding Your System
Chapter 1
1-3
Determine the general criteria for your system. Use the chapters that
follow to guide you through the criteria and choices for selecting the major
Classic PLC-5 programmable controller system elements, as shown in
Figure 1.1.
Figure 1.1
PLCĆ5 Processor System Design Flow
System Design
Determined
Select I/O
modules, terminals
Place
hardware
Select I/O chassis
Select power supply
Select Classic PLCĆ5
processor
Select batteries and
memory modules
Complementary I/O
selected?
Backup system
selected?
Configure processor
communication
Configure Data
Highway Plus
Select programming
software
Data table layout and
processor status
Use fault routines
Choosing
Hardware
and
Placing
System
Hardware
Choosing
Communication
Assigning
Addressing Mode,
Racks, and Groups
I/O update and ladder
program scan times
Planning Your
System Programs
Calculating
Program Timing
and Maximizing
System
Performance
Transfer data in adapter
and scanner modes
Transferring
Discrete and
Block Data
Design SFCs
Select adapter modules
Assign
addressing
We recommend that you first develop a specification that defines your
hardware selection and your programming application. The specification
is a conceptual view of your system. Use it to determine your:
control strategy
hardware selection, layout, and addressing
sequential function chart (SFC)
special programming features
ladder-logic
requirements
Preparing Your
Functional Specification