InstrumentTag (OPC HDA ItemID)

InstrumentTag contains the OPC HDA ItemID for the point. The format of this field depends on your specific OPC HDA Server. Refer to the documentation for the specific server to determine the proper format. This field must exactly match the point defined on the OPC HDA Server. That means punctuation, spaces, uppercase vs. lowercase, and so on.

Length

Depending on the version of the PI API and the Data Archive, this interface supports an InstrumentTag attribute whose length is at most 32 or 1023 characters. The following table indicates the maximum length of this attribute for all the different combinations of PI API and Data Archive versions.

If Data Archive version is earlier than 3.4.370.x or the PI API version is earlier than 1.6.0.2, and you want to use a maximum InstrumentTag length of 1023, you need to enable the PI SDK.

To verify an ItemID, use the PI_HDATool. If the server supports browsing, use List Server's Tags to see a list of defined ItemIDs. Double-clicking an ItemID in the tree will result in the full ItemID being displayed in the Item field. This is the ItemID to use in InstrumentTag.

If the InstrumentTag for a point is longer than 32 characters and PI API 1.6.0.2 or later and PI 3.4.370x PI Data Archive are not installed, put the InstrumentTag in the Extended Descriptor attribute, using the form instr = whatever.the-OPC HDA/server*needs. Note that the InstrumentTag must exactly match the ItemID defined on the OPC HDA Server. If the InstrumentTag contains a comma, enclose the tagname with double quote characters ("), such as:

Instr=”whatever.you, or someone*needs*”