2 Replies Latest reply on Jul 15, 2014 10:35 AM by dstorey

    What are the valid symbols for PI Tag names.


      I did a search and was not able to find a full specification of what the valid naming for tags are.


      The only thing I found is that a tag must start with




      Following this, what other limitations are there?


      For example, is BA:A%B.input or  BA:A*B.input or  BA:A&B.input valid ?




        • Re: What are the valid symbols for PI Tag names.



          This following excerpt will probably clarify your doubt. It was taken from pages 33 and 34 of the PI Server System Management Guide, available for download from the vCampus Library under


          vCampus Library > vCampus PI Products Kit > Server Products > PI Server > PI Server System Management Guide



          The Tag attribute is the name of the point. Each Tag must be unique to a PI System. Since the tag is the name that identifies the point to users, use a consistent tag-naming convention that is meaningful to people in your organization. For example, you could reserve the first two characters of a tag to indicate a unit name or an area of the plant. You could reserve another six characters to match the standard instrument tag, and so on.
          Tags may be any length and can include letters, numbers, and spaces. Tags are subject to the following constraints:
          • The first character must be alphanumeric, an underscore (_), or a percent sign (%).
          • Control characters, such as linefeeds or tabs, are not allowed.
          • The following characters are not allowed:
          * ' ? ; { } [ ] | \ ` ' "
          These characters are allowed, however, in other tag attributes, such as the descriptor.
          Any tags that follow the above rules are, technically, allowed. However, be aware that other applications use some legal characters in special ways. For example, SQL uses the underscore (_) and percent sign (%) as wild cards. Therefore, tags that contain these characters may cause problems with these applications. Similarly, some functions and components restrict the length of tags:
          • PI API functions pipt_tag and pipt_updates truncate the tag to 12 characters. Functions pipt_findpoint, pipt_wildcardsearch, pipt_taglong, and pipt_tagpreferred report only the first 80 characters.
          • PI SQL Subsystem can only process tags with at most 1016 characters. Joins that involve longer tags will return no row found. Queries without joins return rows but truncate tags to 1016 characters.