Events and Callbacks
You can enhance the power and flexibility of your OPC application by using event callbacks. An event is a specific occurrence that can happen while an OPC Data Access client object is connected to an OPC server. The toolbox defines a set of events that include starting, stopping, or acquiring records during a logging task, as well as events for asynchronous reads and writes, data changes, and server shutdown notification.
|Event information for OPC callbacks|
|Clear event log, discarding all events|
|Event log summary for OPC events|
|opcda Object Properties||Configure OPC DA client|
|dagroup Object Properties||Configure OPC |
|daitem Object Properties||Configure OPC |
- Use the Default Callback Function
Learn the basics of events and callbacks.
- Retrieve Event Information
Access the information generated with each event.
- Create and Execute Callback Functions
Write a callback function and associate it with an event callback.
- Event Types
Learn all the event types supported by the toolbox.