The PIAnnotation object is used to annotate a PIValue in the PI System archive. It has a Value which can be a VARIANT or a file. If it is a file, the contents of the file are stored in the annotation and can be restored to disk later.
A PIAnnotation is always stored as part of a PIAnnotations collection. This collection is what is stored along with the PIValue.
PIAnnotation objects have an MTPIProperties collection; allowing structured data to be stored. This collection is a free-threaded version of the PIProperties collection.
A PIAnnotation can only be created when it is added to a PIAnnotations collection.