Allen-Bradley PLC-5 User Manual

1 Publication 1785-UM012D-EN-P - July 2005
Chapter 16
Using Main Control Programs
Using This Chapter
Selecting Main Control
Programs
You can have as many as 16 control programs active at one time. Each of
these programs is called a “main control program” (MCP). You can define
one MCP for each particular machine or function of your process. This lets
you separate sequential function charts (SFCs), ladder logic, and structured
text to better modularize your process and make troubleshooting easier.
A main control program can be an SFC numbered 1-999; it can also be a
ladder or structured-text program numbered 2-999 in any program file. You
can use any mix of SFC, ladder, and structured-text programs to define 16
main control programs. One data table is used by all MCPs (i.e., you do not
have a separate data table for each MCP).
For Information About Go to Page
Selecting main control programs
16-1
Understanding how the controller interprets
MCPs
16-2
Configuring MCPs
16-3
Monitoring MCPs
16-5
Consider Using this Technique If You are
SFC defining the order of events in the process
Ladder Logic
• more familiar with ladder logic than with programming
languages such as BASIC
• performing diagnostics
Structured Text
• more familiar with programming languages such as
BASIC than with ladder logic
• using complex mathematical algorithms
• using program constructs that repeat or “loop”
• creating custom data-table monitoring screens

Allen-Bradley PLC-5 Specifications

General

Programming Software	RSLogix 5
Programming Languages	Ladder Logic
Power Supply	120/240V AC or 24V DC
Communication Ports	DH+, Remote I/O, Ethernet/IP, ControlNet
Operating Temperature	0 to 60°C (32 to 140°F)
Relative Humidity	5 to 95% non-condensing
Memory	Up to 64K words (user program and data)

Summary

Preface

Manual Overview

Outlines the manual's three main sections: Design, Operate, and Maintain.

Chapter 1 Understanding Your Programmable Controller

Lay Out the System

Guides on determining network configuration and component placement for PLC-5 systems.

Programming Features

Highlights the programming features of a PLC-5 controller, including ladder logic and SFCs.

Chapter 2 Selecting and Placing I/O

Selecting I/O Modules

Guides on selecting I/O modules to interface with machines and processes.

Chapter 3 Placing System Hardware

Determining the Proper Environment

Details acceptable environmental conditions for controller placement.

Grounding Your System

Provides information on proper grounding guidelines for system hardware.

Chapter 4 Addressing I/O and Controller Memory

I/O Addressing Concept

Explains how controller memory segments are used to address I/O terminals.

Assigning Racks

Details how chassis size and addressing mode determine the number of I/O racks.

Chapter 6 Communicating with Remote I/O

Designing a Remote I/O Link

Outlines steps and guidelines for designing a remote I/O link.

Chapter 8 Communicating with Extended-Local I/O

Configuring the Controller as an Extended-Local I/O Scanner

Guides on configuring channel 2 for extended-local I/O as a scanner.

Chapter 10 Communicating with Devices on a Serial Link

Configuring Channel 0

Explains how to configure channel 0 for DF1 point-to-point, master, slave, or user mode.

Chapter 11 Communicating with Devices on an Ethernet Network

Configuring Channel 2 for Ethernet Communication

Guides on configuring channel 2 for Ethernet communication using manual or BOOTP methods.

Using Advanced Ethernet Functions

Explains advanced functions like broadcast address, subnet masks, and gateways.

Chapter 12 Protecting Your Programs

Passwords and Privileges

Explains how passwords and privileges restrict access to controller files and functions.

Chapter 13 Programming Considerations

Forcing

Explains how to turn input/output bits on/off for testing purposes.

Extended Forcing

Describes how to force discrete I/O, analog I/O, and block-transfer data words.

Chapter 15 Preparing Fault Routines

Understanding the Fault Routine Concept

Explains how fault routines execute when a major fault is encountered.

Monitoring Faults

Describes how to monitor controller faults using the status screen.

Appendix F Troubleshooting

PLC-5 controller

Lists general problems for PLC-5 controllers, probable causes, and recommended actions.

Extended-Local I/O system

Offers troubleshooting guidance for the 1771-ALX adapter module.

Appendix G Cable Reference

Channel 0 Pin Assignments

Shows pin assignments for channel 0 (RS-port) for different serial communication modes.

Ethernet Cable Connections

Describes Ethernet cable connections and transceiver specifications.