Omron Product Terminology; Overview Of Pc Operation - Omron SYSMAC CV Series Operation Manual

Overview of PC Operation

Controlled System and
Control System
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OMRON Product Terminology

1-5 Overview of PC Operation
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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 memory, 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 signals 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 connector 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 inputs and outputs. It all depends
on what aspect of PC operation is being talked about.
The Control System includes the PC and all I/O devices it uses to control an ex-
ternal 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 controlled sys-
tem, e.g., a motor used to drive a conveyor belt.
OMRON products are divided into several functional groups that have generic
names. Appendix A Standard Models lists products according to these groups.
The term Unit is used to refer to all of the OMRON PC products. Although a Unit
is any one of the building blocks that goes together to form a CV-series PC, its
meaning is generally, but not always, limited in context to refer to the Units that
are mounted to a Rack. Most, but not all, of these products have names that end
with the word Unit.
The largest group of OMRON products is the I/O Units. These include all of the
Rack-mounting Units that provide non-dedicated input or output points for gen-
eral use. I/O Units come with a variety of point connections and specifications.
Special I/O Units are dedicated Units that are designed to meet specific needs.
These include Position Control Units, High-speed Counter Units, and Analog I/O
Units. This group also includes some programmable Units, such as the ASCII
Unit, which is programmed in BASIC.
CPU Bus Units connect to the CPU bus and must be mounted on either the
CPU Rack or a Expansion CPU Rack. These include the SYSMAC NET Link
Unit, SYSMAC LINK Unit, SYSMAC BUS/2 Remote I/O Master Unit, and BASIC
Unit.
Link Units are used to create communications links between PCs or between
PCs and other devices. Link Units include SYSMAC NET Link Unit, SYSMAC
LINK Unit, and, sometimes, SYSMAC BUS/2 Remote I/O Master Unit.
Other product groups include Programming Devices, Peripheral Devices,
and DIN Track Products.
The following are the basic steps involved in programming and operating a CV-
series PC. Assuming you have already purchased one or more of these PCs,
you must have a reasonable idea of the required information for steps one and
two, which are discussed briefly below. The relevant sections of this manual that
provide more information are listed with relevant steps.
1. Determine what the controlled system must do, in what order, and at what
times.
2. Determine what Racks and what Units will be required. Refer to the CV-se-
ries PCs Installation Guide . If a Link System is required, refer to the ap-
propriate System Manual .
Section 1-5