This document specifies a revised version of the OLE Automation interface that was specified in Release 1.0 of the OPC specification. There were several reasons for these revisions. The most important are as follows:
This document assumes that the reader is familiar with the information provided on the OPC Data Access Custom Interface Specification. That document provides an Overview of the OPC functionality as well as detailed descriptions of the behavior of the various functions.
- Make the interface easier to use by the Visual Basic Programmer
- Take advantage of newer features of Visual Basic (such as events)
- Allow the creation of a common wrapper DLL which could be shared by all vendors