Opc data Access Automation Specification

4.6

 

OPCItem Object 

Description 

An OPC Item represents a connection to data sources within the server. Associated with each item 

is a Value, Quality and Time Stamp.  The value is in the form of a VARIANT, and the Quality is 

similar to that specified by Fieldbus.   

Syntax OPCItem 

4.6.1

 

Summary of Properties 

Parent ClientHandle 

ServerHandle 

AccessPath AccessRights 

ItemID 

IsActive RequestedDataType 

Value 

Quality TimeStamp 

CanonicalDataType 

EUType EUInfo   

4.6.2

 

 Summary of Methods 

Read Write  

 

4.6.3

 

OPCItem Properties 

4.6.3.1

 

Parent  

Description 

 (Read-only) Returns reference to the parent OPCGroup object. 

Syntax 

 Parent As OPCGroup 

4.6.3.2

 

ClientHandle 

Description 

 (Read/Write) A Long value associated with the OPCItem. Its purpose is for the client to quickly 

locate the destination of data. The handle is typically an index, etc. This handle will be returned to 

the client along with data or status changes by OPCGroup events. 

Syntax 

ClientHandle As Long 

Example 

Dim AnOPCItem as OPCItem 

Set OPCItem = GetOPCItem(SomeItemServerHandle) 

VB Syntax Example (getting the property): 

Dim CurrentValue As Long 

Dim SomeValue As Long 

CurrentValue = AnOPCItem.ClientHandle 

VB Syntax Example (setting the property): 

AnOPCItem.ClientHandle = SomeValue 

 

72 

 

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OPC Data Access Automation Specification2.02