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What is the Syntax to access a symbol using the OPCXML-DA

Goals and Symptoms
Provide the syntax to use for accessing a symbol using OPCXML-DA.

Facts and Change
OFS

Causes and Fixes​
The following example demonstrate how to directly access a symbol in a PLC using OPCXML-DA.  The symbol in the PLC
can be accessed by OFS using either the 'Data Dictionary' or the '.XVM' file  method.   It is accomplished using the OPC property
'ItemPath' and 'ItemName'.
 
e.g., 

Given the following:
  • The Alias for the device name in in OFS is defined as  'myAlias'
  • The symbol name in the Unity application is defined as 'CPU227OPC'
  • ItemPath= "http://stationname/Website/OFS/ws/OPCXMLDa.asmx"
  • ItemName= myAlias!CPU227OPC

The syntax to directly access the the symbol using OPCXML-DA is:defined as:
 
http://stationname/Website/OFS/ws/OPCXMLDa.asmx/myAlias!CPU227OPC

 
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