Opc data Access Automation Specification

2.5

 

Introduction to Exceptions and Events 

2.5.1

 

Exceptions 

Most properties and methods described here communicate with an OPC Custom Server. In OLE Automation, there is no 

easy way to return an error when accessing a property.  The best way to resolve this is for the automation server to 

generate an exception if such an error occurs in the underlying data source. This means that the client needs to have 

exception logic in place to handle errors.  

Errors that occur when setting a property are reported using the standard Visual Basic Err object.  Refer to Appendix A - 

OPC Automation Error Handling for more details on handling errors.