copyright 1998 intellution, inc. all rights reserved opc alarms and events technical overview tm ole...
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Copyright 1998 Intellution, Inc. All Rights Reserved
OPC Alarms and Events OPC Alarms and Events Technical OverviewTechnical Overview
TM
OLE for Process Control and Factory
AutomationAl Chisholm - OPC Technical Chairman11/98
Copyright 1998 Intellution, Inc. All Rights Reserved
TopicsTopics
• A review of the Problem• Design Features• Assumptions about the Applications• The Objects• The functionality they provide
Copyright 1998 Intellution, Inc. All Rights Reserved
Why is OPC needed?Why is OPC needed?
SoftwareDriver
SoftwareDriver
SoftwareDriver
SoftwareDriver
DisplayApplication
TrendApplication
ReportApplication
Copyright 1998 Intellution, Inc. All Rights Reserved
How does OPC Solve the Problem?How does OPC Solve the Problem?
SoftwareDriver
SoftwareDriver
SoftwareDriver
SoftwareDriver
OPC OPC OPC OPC
DisplayApplication
TrendApplication
ReportApplication
OPC OPC OPC
Copyright 1998 Intellution, Inc. All Rights Reserved
Where does OPC Alarms Fit?Where does OPC Alarms Fit?
Low level sensorsTypically use a dedicated
Hardware Interface and protocolDevice Specific I/O Control
Data MonitorSubSystem
OPC
OPC (via DCOM)can also be used between subsystemsand Management Consoles
OPC is generally usedbetween Monitoring
applications and I/O specificsoftware drivers
Copyright 1998 Intellution, Inc. All Rights Reserved
What Does OPC Provide?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
OPC Interfaces
Sensor Alarms
CommStatus
System Performance
OS Statistics
Copyright 1998 Intellution, Inc. All Rights Reserved
General Features of OPC AlarmsGeneral 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)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)Fundamental Assumptions (II)
• Alarm State Information includes– Enabled, Active, Acknowledged
• Areas• Source Names• Categories• Filtering
Copyright 1998 Intellution, Inc. All Rights Reserved
The Logical Object ModelThe Logical Object Model
OPCServer
Subscription
CustomInterfaces
Subscription Subscription
Conditions and Events...
Copyright 1998 Intellution, Inc. All Rights Reserved
Typical Server DesignTypical 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 InterfacesThe Server Interfaces
• The server is a COM object which provides:
• IOPCCommon• IOPCEventServer• IConnectionPointContainer
OPCServer
Copyright 1998 Intellution, Inc. All Rights Reserved
The Subscription Object InterfacesThe Subscription Object Interfaces
• The Subscription is a COM object which provides:
• IOPCEventSubscriptionMgt• IConnectionPointContainer
OPCServer
Subscription
Copyright 1998 Intellution, Inc. All Rights Reserved
The Client Side IntefacesThe Client Side Intefaces
• The Client provides 2 COM interfaces that the server can call
• IOPCShutdown• IOPCEventSink Server Object
Subscription Object(s)
Client
IOPCEventSink
IOPCShutdown
Copyright 1998 Intellution, Inc. All Rights Reserved
Client/Server ConnectionClient/Server Connection
Client Server
Subscription
OnEvent
1
2
3CPCCP
OnEvent4
Copyright 1998 Intellution, Inc. All Rights Reserved
Performance and FlexibilityPerformance 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.
Copyright 1998 Intellution, Inc. All Rights Reserved
SummarySummary
• 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
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