Applies To:
  • CitectSCADA 5.xx, 6.xx, 7.00
  • CitectHMI 5.xx, 6.xx, 7.00
Summary:
I would like to access quality and timestamp information about an OPC array tag. What variable address format should I use?
 

Solution:
If your OPC server supports array items and you would like to access them as Citect array tags then you should use the following variable address format:

Fred!A[10]

This would address an OPC item called 'Fred', asking for Citect to treat it as an array of 10 elements.

If you want to know the quality of the OPC item called 'Fred' then the format you should use in the variable address is:

Fred!Q

You can not get access to separate qualities and timestamps of individual elements of 'Fred' because this information applies to the OPC item as a whole.

Some people have tried addresses such as OPCItem!A[10]!Q and found that it did not work. The formats specified above should be used instead.

 
Keywords:
OPC array quality timestamp millisecond QTM  

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