User manual

Computer Gateway User Manual 4-101 5/96
4.8.2
When snapshot data (history type 0, 9, 10, or 11) is requested, all
the data returned is controlled by the time interval specified in the
request (60-, 5-, 10, or 20-second intervals, respectively).
This means that, for example, if a 5-second interval is requested,
and some of the points requested are in 60-second history groups,
then each of the 60-second points has 11 "fast collection not
configured" records (each with the appropriate 5-second
timestamp) returned between the 60-second time values that are
available. Any points in 10- or 20-second history groups are
handled similarly. The following illustration shows when data
records for each history group can be returned when a 5-second
interval is requested. (Blank elements in the illustration indicate
when a "fast collection not configured" record is returned instead
of a data record.)
Timestamp 5-Second Group 10-Second Group 20-Second Group 60-Second Group
00:00:00 data record data record data record data record
00:00:05 data record
00:00:10 data record data record
00:00:15 data record
00:00:20 data record data record data record
00:00:25 data record
00:00:30 data record data record
00:00:35 data record
00:00:40 data record data record data record
00:00:45 data record
00:00:50 data record data record
00:00:55 data record
00:01:00 data record data record data record data record
4.8.2.1 Value-Type Meanings for Snapshots
0 = Normal Data: Value returned is analog (real) data.
1 = Nonstandard: not applicable
2 = Digital Value: Value returned is a self-defined enumeration.
3-4 = not used
5 = Time Change: A time change occurred and data for one minute is missing;
value field contains NaN
6 = Outage: History module was not in service; value field contains NaN.
7 = No Data: The Data Owner was not in service; value field contains NaN.
8-10 = not used
11 = Collection Inhibited: History collection was not enabled; value field
contains NaN.
12 = Not in History: Requested data was outside span of the History file; value
field contains NaN.
13 = Time Change nonstandard: not applicable
14 = Fast Collection is not configured; value field contains NaN.