Rockwell Automation T7832 ICS Regent+Plus Historian Packages for Winterpret - Manual (Page 18)

Historian Package for W INTERPRET (T7832)
1 8
Industrial Control Services
Where:
# frames = Period / Sample Time
QtyIO = Number of digital input modules, digital
output modules, analog I/O points, and
thermocouple inputs defined in function
block
QtySVR = Number of shared variable registers
defined in function block
QtySVFP = Number of shared variable floating point
registers defined in function block
If this calculation produces a number greater than 65534 you
must do one of the following:
1. Increase the Sample Time, thus reducing the number of
frames.
2. Decrease the Period, thus reducing the number of frames.
3. Reduce the number of variable entries defined in the
function block. You may need to split up your variable
entries into more than one function block to keep the size
of each historical buffer less than 65534 bytes while
maintaining the same Period and Sample Time.
To help gauge the limits on the historical buffer the chart in
Figure 10 graphs number of variable entries vs. number of
frames for the maximum size historical buffer. In this chart
the variable entries are assumed to be digital input modules,
digital output modules, analog I/O points, thermocouple
inputs or shared variable registers (they all require 2 bytes
per frame). If you plan on using floating point registers, count
them as two variable entries (they require 4 bytes per frame)
before referring to the chart.