Issue 4752: Management of events appearing in a scan cycle                                                                                                                                                          (dais-ftf)
Source: ABB Power Technologies, Power Automation & Substat (Mr. Lars-Ola Osterlund, lars-ola.g.osterlund@se.abb.com)
Nature: Uncategorized Issue
Severity: 
Summary: A descrete value may change multiple times within a scan cycle before it is reported to clients. Clients may want to get all the changes but still at a low scan cycle to optimize performance
Resolution: This function is supported by HDAIS. Use HDAIS when needed. No changes to DAIS specification.
Revised Text: 
Actions taken:
December 14, 2001: received issue
October 23, 2002: closed issue
Discussion: 
A server shall keep a history of changes and per group report all changes not reported since the last report for that group. A quality of service measure is included in the DAIS::ServerState to tell if a server support this functionality. The quality of service shall also indicate the maximum number of changes that can be kept in the history per item. An ItemError indicating more changes than supported by the history is added.
End of Annotations:=====
Management of events appearing in a scan cycleA descrete value may
change multiple times within a scan cycle before it is reported to
clients. Clients may want to get all the changes but still at a low
scan cycle to optimize performance.

A server shall keep a history of changes and per group report all
changes not reported since the last report for that group. A quality
of service measure is included in the DAIS::ServerState to tell if a
server support this functionality. The quality of service shall also
indicate the maximum number of changes that can be kept in the history
per item. An ItemError indicating more changes than supported by the
history is added