Omron CX-SUPERVISOR - V2.0, Руководство пользователя

Страница: 252 / 370

OMRON CHAPTER 14 – Using CX-Supervisor as an OPC Client
Release 2.0 Page 229
Chapter 14
Using CX-Supervisor as an OPC Client
This chapter introduces OPC Server to a new user, and explains how to use CX-Supervisor as an
OPC Client.
An Overview of OPC
What is OPC?
OPC
stands for
O
LE for
P
rocess
C
ontrol, and is a standard published by the OPC Foundation.
The basic aim of the OPC standard is to allow hardware vendors to produce software drivers (called
OPC Servers) and for software vendors to produce applications (called OPC Clients) which use a
standard method for data interchange. This allows software and hardware from different vendors to
be used together.
Based on Microsoft’s OLE (now ActiveX), COM (component object model) and DCOM (distributed
component object model) technologies, OPC consists of a standard set of interfaces, properties, and
methods for use in process-control and manufacturing-automation applications. The ActiveX/COM
technologies define how individual software components can interact and share data. Backed by
Microsoft’s NT technology, OPC provides a common interface for communicating with diverse
process-control devices, regardless of the controlling software or devices in the process. The goal of
the standard is Plug-and-Play, a concept developed by Microsoft and a number of other companies a
few years ago. By using a standard way of configuring computer hardware (and software interfaces)
automatically, a device will easily connect to another and immediately work without the need for
lengthy installation procedures or complex configuration. Instead of having to learn how to use 100
or more custom toolkits, users will only have to learn one set of tools, because all OPC drivers will
work the same way. OPC’s purpose is to compel the automation industry suppliers to push all device
drivers toward a standard form. Essentially, OPC defines a common interface that permits interface
development work to be performed once and then easily reused. The OPC standard requires hardware
suppliers to provide front-line data collection and distribution. They are the most familiar with how to
access the device’s internal data efficiently. These devices then become OPC servers, providing data
to OPC client applications consistently. Application developers can then write code in any language
deemed appropriate.
The latest version of the OPC standard is version 2. This replaces the earlier version 1 standard.
CX-Supervisor uses an OPC version 2 interface to connect to an OPC Server which is version 2
compliant. Note that the OPC version 1 interface has been superseded, and is not supported.
Users of CX-Supervisor may need some basic understanding of OPC. For more information on OPC,
see the OPC Foundation web site at
www.opcfoundation.org .
For instructions on configuring your DCOM settings for connection to remote PCs, see Appendix A.