The KeyFrameCount with DataType UInt32 is the multiplier of the PublishingInterval that defines the maximum number of times the PublishingInterval expires before a key frame message, with all field values, is received.
For DataSets that provide cyclic updates, the value shall be greater than or equal to 1. For non-cyclic DataSets, like PublishedEvents, that provide event based DataSets, the value shall be 0.