Rockwell Automation 1404-M4_M5_M6_M8 Powermonitor 3000 User Manual, Firmware rev. 3.0 or LATER - Manual (Page 149)

Publication 1404-UM001F-EN-P - November 2009 149
Data Logging Chapter 7
Calculating Trend Log Depth
How long the Trend Log takes to fill may be as little as 90 minutes or
as long as 2 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)
INT (x) = The integer portion of x
TIP
If you use the power monitor with RSEnergyMetrix energy logging
software, 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
automatic data repopulation of the energy database.
EXAMPLE
For example, if P=3 and F=0, we will get this result.
7 INT ×
65536
12 6 16 + +
---------------------------
⎝ ⎠
⎛ ⎞
INT 1927.53 ( ) 7 1927 Ч 13489 = = =