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OPC Alarms and Events Technical Overview

OLE for Process Control and Factory Automation

Topics

Why is OPC needed?

How does OPC Solve the Problem?

Display Application OPC Trend Application OPC Report Application OPC OPC Software Driver OPC Software Driver OPC Software Driver OPC Software Driver Copyright 1998 Intellution, Inc. All Rights Reserved

Where does OPC Alarms Fit?

OPC (via DCOM)can also be used between subsystems and Management Consoles OPC is generally used between Monitoring applications and I/O specific software drivers Data Monitor SubSystem OPC Device Specific I/O Control Low level sensors Typically use a dedicated Hardware Interface and protocol Copyright 1998 Intellution, Inc. All Rights Reserved

What Does OPC Provide?

• • • • • Alarms on sensor data - temp, pressure, flow Alarms on Control parameters - open, close, run, stop Updates on Status information – Status of the hardware connection – Status of the local software and subsystem Completion of system sequences such as batches OPC can expose any data available Sensor Alarms OPC Interfaces Comm Status System Performance Copyright 1998 Intellution, Inc. All Rights Reserved OS Statistics

General Features of OPC Alarms

• • • • • Based on COM to leverage Microsoft ‘Plumbing’ Flexible - to support many applications Efficient - to support large applications Hi performance - well behaved on a Network Easy to understand Copyright 1998 Intellution, Inc. All Rights Reserved

Fundamental Assumptions (I)

• • • • Each OPC Server such as Alarms and Events is a Separate Object which complements the other OPC Objects Alarms and Events is primarily Subscription based Event Types – Simple, Tracking, Condition (Alarm) Conditions – Single State, Multi State Copyright 1998 Intellution, Inc. All Rights Reserved

Fundamental Assumptions (II)

The Logical Object Model

Custom Interfaces OPCServer Subscription Subscription Conditions and Events...

Typical Server Design

OPC/COM Interfaces OPC Subscription Object Management Condition Monitoring and Optimization Device Specific Protocol Logic (if needed) Hardware Connection Management (if needed) Copyright 1998 Intellution, Inc. All Rights Reserved

The Server Interfaces

• The server is a COM object which provides: • • •

IOPCCommon IOPCEventServer IConnectionPointContainer

The Subscription Object Interfaces

• The Subscription is a COM object which provides: • •

IOPCEventSubscriptionMgt IConnectionPointContainer

The Client Side Intefaces

• The Client provides 2 COM interfaces that the server can call • •

IOPCShutdown IOPCEventSink

Client/Server Connection

Performance and Flexibility

• • OPC Alarms and Events is complete, powerful and flexible because it is a combination of the best ideas of many of the best companies in our business.

OPC Alarms and Events is Fast because it was designed from the start with networking in mind.

Summary

• • • • • • The OPC Alarms and Events Interfaces: Support exception based updates via Filtered Subscriptions Are designed to be vendor neutral Allow connections to both simple and complex devices Are optimized for use over a network www.opcfoundation.org

Notes to Presenter

Transcript Notes to Presenter

OLE for Process Control and Factory Automation

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