Rockwell Automation T7832 ICS Regent+Plus Historian Packages for Winterpret - Manual (Page 9)

Historian Package for W INTERPRET (T7832)
P D - 7 0 4 2 M a r c h , 0 6
9
Count register for changes to detect when there are new
events that have been recorded and direct appropriate plant
personnel to monitor and collect the SOE buffer using
W
INTERPRET .
Size Field
A constant must be entered into the Size field to indicate the
size of the events buffer. The larger the buffer, the more
events can be recorded without old events being overwritten,
and the more space the function block utilizes in the Regent.
The maximum value for the events buffer is 32,727. This
represents 32,727 words of space (or 65,454 bytes of Regent
memory) in which to store events. The maximum buffer space
required to store the change-of-state of one variable is six
words (three words for the entry and three words for the time
stamp).
Therefore, the amount of Regent memory required to store the
change-of-state of 1,000 variables of this type is:
1,000 events x (3 words per event + 3 words per timestamp) =
6,000 words (or 12,000 bytes of Regent memory)
Variables that change state within the same scan require only
one time stamp to be recorded. Therefore, the buffer space
used by two events that occur within the same scan can be as
much as:
(2 events * 3 words per event) + 3 words per timestamp =
9 words (or 18 bytes of Regent memory)