Rockwell Automation FactoryTalk Historian SE DataLink 4.2 User Guide - Manual (Page 33)

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Time stamps are displayed to match the specified row or column
orientation. If all time stamps are shown, the order from left column to
right or top row to bottom is start time, end time, minimum value time,
maximum value time, event value.
Show Percent Good
Select show percent good to display the percentage of time for which
good values are returned over the total time range of the array. Percent
good values are typically added in a column to the right or a row below
retrieved values.
Good values are event values determined to be valid by the FactoryTalk
Historian server, and not in an error state. The percentage of good values
helps in assessing the reliability of calculations built on FactoryTalk
Historian point values, particularly if calculated values are to be used in
further calculations.
For example, totals may still be calculated over a time range even if some
of the data are bad. The resulting time-weighted total value equals the total
divided by the fraction of the interval where good data is available.
However, this normalization assumes that the average over the time range
with bad data is equivalent to the average value over the entire time range,
which becomes less reliable if a large fraction of the time range contains
bad data.
Show Value Attributes
Select show value attributes to display extended status bits associated
with returned event values. The returned bits correspond to value attributes
stored in FactoryTalk Historian, and may be one of the following:
 A = annotated, indicating a comment has been added to the event.
 S = substituted, indicating the event value has been changed from its
original value.