Rockwell Automation 1404-M4_M5_M6_M8 Powermonitor 3000 User Manual, PRIOR to Firmware rev. 3.0 - Manual (Page 141)

Publication 1404-UM001D-EN-E - October 2004
Data Logging 7-9
Calculating Trend Log Depth
How long the Trend Log takes to fill may be as little as 90 minutes or
as long as 5 years depending on how you configure the log. These
formulas will help you configure the trend log to obtain the results
you want. Round off any results to the next lower integer.
Trend Log Depth Formula
This formula returns the number of records in the trend log for the
number of parameters logged. To determine the length of time this
represents, multiply the result by the trend log interval.
Where:
D = Depth of the trend log in records
F = Fill mode (0 = fill and hold, 1 = overwrite)
P = Parameters per record (1 - 16)
Parameters per Record formula
If your application requires a certain number of records or time to
preserve logged information, this formula returns the number of
parameters per record allowed.
TIP
If you use the Powermonitor 3000 with an energy
logging software such as RSEnergyMetrix, you
should coordinate the parameters selected for the
Trend Log with those logged by the software. This
allows for the energy logging software to poll the
Trend Log data, allowing for less frequent polling
and automatic data repopulation of the energy
database.
D
7 F –
( ) 65524 •
P 4
• ( ) 6
+
-------------------------------------- =
P
7 F –
( ) 16381 •
D
-------------------------------------- 1.5 – =