Opc data Access Automation Specification

4.4.6.2

 

AsyncReadComplete  

Description 

This event fires when an AsyncRead is completed.  

Syntax 

AsyncReadComplete (TransactionID As Long, NumItems As Long, ClientHandles() As Long, 

ItemValues() As Variant, Qualities() As Long, TimeStamps() As Date, Errors() As Long) 

 

Part Description 

TransactionID 

The client specified transaction ID.  

NumItems 

The number of items returned 

ClientHandles 

Array of client item handles for the items  

ItemValues 

Array of values. 

Qualities 

Array of Qualities for each item's value. 

TimeStamps 

Array of UTC TimeStamps for each item's value. If the device cannot 

provide a timestamp then the server will provide one. 

Errors 

Array of Long’s indicating the success of the individual item reads. 

This indicates whether the read succeeded in obtaining a defined 

value, quality and timestamp.  NOTE any FAILED error code 

indicates that the corresponding Value, Quality and Time stamp are 

60 

 

---

OPC Data Access Automation Specification2.02 

UNDEFINED. 

 

Example 

Dim WithEvents AnOPCGroup As OPCGroup 

Private Sub AnOPCGroup_AsyncReadComplete (TransactionID As Long, NumItems As Long, 

ClientHandles() As Long, ItemValues() As Variant, Qualities() As Long, TimeStamps() As Date) 

‘ write your client code here to process the data change values  

End Sub