OMRON C60H-C5DR-DE-V1 Programmable Controllers

OMRON C60H-C5DR-DE-V1   Programmable Controllers

monitors the status of all input points and turns ON or OFF corresponding

input bits accordingly.

There are also output bits in memory that are allocated to output points on

Units through which output signals are sent to output devices, i.e., an output

bit is turned ON to send a signal to an output device through an output point.

The CPU periodically turns output points ON or OFF according to the status

of the output bits.

These terms are used when describing different aspects of PC operation.

When programming, one is concerned with what information is held in mem

ory, and so I/O bits are referred to. When talking about the Units that connect

the PC to the controlled system and the places on these Units where signal

enter and leave the PC, I/O points are referred to. When wiring these I/O

points, the physical counterparts of the I/O points, either terminals or connec

tor pins, are referred to. When talking about the signals that enter or leave

the PC, one refers to input signals and output signals, or sometimes just in

puts and outputs. It all depends on what aspect of PC operation is being

talked about.

Controlled System and

Control System

The Control System includes the PC and all I/O devices it uses to control an

external system. A sensor that provides information to achieve control is an

input device that is clearly part of the Control System. The controlled system

is the external system that is being controlled by the PC program through

these I/O devices. I/O devices can sometimes be considered part of the con

trolled system, e.g., a motor used to drive a conveyor belt.

1-4 OMRONProductTerminology

OMRONproducts are divided into several functional groups that have gener

ic names. Appendix A Standard Models list products according to these

groups. The term Unit is used to refer to all of the OMRON PC products.

Product groups include Programming Devices, Peripheral Devices, and DIN

Rail Products.

1-5 Overview of PC Operation

The following are the basic steps involved in programming and operating a

C20H-type PC. Assuming you have already purchased one or more of these

PCs, you would be familiar with steps one and two, which are discussed

briefly below. This manual is written to explain steps three through six, eight,

and nine. The relevant sections of this manual that provide more information

are listed with each of these steps.

1. 2. 3...

1. Determine what the controlled system must do, in what order, and at

what times.

2. Determine what Units will be required and whether your system configu

ration will require an Expansion I/O Units. Refer to the Mini H-type PC

Installation Guide.

3. On paper, assign all input and output devices to I/O points on Units and

determine which I/O bits will be allocated to each.

4. Using relay ladder symbols, write a program that represents the se

quence of required operations and their inter-relationships. Be sure to

also program appropriate responses for all possible emergency situ

ations. (Refer to Section 4 Writing and Entering Programs, Section5In

struction Set, and Section 6 Program Execution Timing)

5. Input the program and all required operating parameters into the PC.

(Refer to Section 7 Program Debugging and Execution

6. Debug the program, first to eliminate any syntax errors, and then to find

execution errors. (Refer to Section 7 Program Debugging and Execution

and Section 9 Troubleshooting)

7. Wire the PC to the controlled system. This step can actually be started

as soon as step 3 has been completed. Refer to the C20H, C28H, C40H

Installation Guide and to Operation Manuals and System Manuals for

details on individual Units.

8. Test the program in an actual control situation and carry out fine tuning

as required. (Refer to Section 7 Program Debugging and Execution and

Section 9 Troubleshooting)

Control System Design

Designing the Control System is the first step in automating any process. A

PC can be programmed and operated only after the overall Control System is

fully understood. Designing the Control System requires, first of all, a thor

ough understanding of the system that is to be controlled. The first step in

designing a Control System is thus determining the requirements of the con

trolled system.

Input/Output Requirements The first thing that must be assessed is the number of input and output points

that the controlled system will require. This is done by identifying each device

that is to send an input signal to the PC or which is to receive an output sig

nal from the PC. Keep in mind that the number of I/O points available de

pends on the configuration of the PC. Refer to 3-3 IR Area for details on I/O

capacity and the allocation of I/O bits to I/O points.

Sequence, Timing, and

Relationships

Next, determine the sequence in which control operations are to occur and

the relative timing of the operations. Identify the physical relationships be

tween the I/O devices as well as the kinds of responses that should occur

between them.

For instance, a photoelectric switch might be functionally tied to a motor by

way of a counter within the PC. When the PC receives an input from a start

switch, it could start the motor. The PC could then stop the motor when the

counter has received a specified number of input signals from the photoelec

tric switch.

Each of the related tasks must be similarly determined, from the beginning of

the control operation to the end.