Special considerations for tag names
- Last UpdatedFeb 27, 2025
- 2 minute read
There are some limitations to be aware of when replicating to AVEVA PI Server.
Tag Name Length Limitations
The PI Server limits tag names to a maximum length of 200 characters. If the source tag name from the Historian is longer than 200 characters:
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The destination tag name on the PI Server is truncated at 200 characters
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The attribute name in the PI Asset Framework (AF) hierarchy is truncated at 200 characters, then the tag's ID (a GUID) is appended to preserve uniqueness.
Character Limitations
Certain characters are not supported for tag names by the PI Server. The following rules apply to tag names in AVEVA PI Server:
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The first character of a tag name must be alphanumeric, an underscore (_), or a percent sign (%)
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Double-byte characters are not supported
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Control characters, such as line feeds and tabs, are not supported
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The following characters are also not supported: * ? ; { } [ ] | \ ` ' "
If a tag's engineering unit contains an unsupported character, the tag's unit is set to None when it is replicated to the PI server.
If the ReplicationDefaultPrefix contains an unsupported character, the default value of the server's name is used.
If an unsupported character is detected in the source tag name, the AF attribute name uses the destination tag name instead. If the destination tag name also contains an unsupported character, the Operations Control Management Console detects the unsupported character and displays an error. The tag cannot be replicated until a valid destination tag name is set.
The Location tag extended property is used to build the AF hierarchy. If the Location property contains an unsupported character, it cannot be used and the tag is placed at the root of the hierarchy instead.
For more information about supported characters, refer to the following topics in the AVEVA PI Server documentation: