Message restrictions

In addition to any limitations defined by the OMF specification, the PI Web API adds the following restrictions:

• The following characters cannot be included in strings, unless specified otherwise, because they are reserved in PI AF and Data Archive:

  
  * (asterisk)
  ? (question mark)
  ; (semicolon)
  { (left curly bracket)
  } (right curly bracket)
  [ (left square bracket)
  ] (right square bracket)
  \ (reverse solidus)
  ' (apostrophe)
  " (quotation mark)
  | (vertical bar)

• Static type messages must have exactly one index. The type must be string, and the format must be unspecified.

• Dynamic type messages must have exactly one index. The type must be string, and the format must be date-time.

• The array and object property types are not supported.

• The float16 property format is not supported.

• The reftypeid property keyword only supports enumeration types.

• Type-to-type link messages are not supported.

• Property nullability may be limited by other information on the type; see Nullability.

• Unit of measure (UOM) full names are always case-insensitive, but UOM abbreviations may be case-sensitive. Case sensitivity of UOM abbreviations depends on the PI Asset Framework server version and its settings. See Case sensitivity of UOM abbreviations in the Asset Framework and PI System Explorer guide and then review your configuration to determine whether UOM abbreviations are case-insensitive in your environment.