Rockwell Automation 1756-CFM ControlLogix Configurable Flowmeter Module - Manual (Page 143)

143 Rockwell Automation Publication 1756-UM010B-EN-P - December 2011
Frequency Accuracy 143
Frequency Accuracy in
Totalizer Mode
There are two steps to calculating frequency accuracy in
totalizer mode.
1. Calculate frequency accuracy.
2. Determine the application’s operating conditions and add the error for
those conditions to the value obtained in step 1.
The following values must be added to your frequency accuracy results
in totalizer mode:
 Crystal error - 0.005% @ 25°C
 Drift and crystal error - 0.01% from 0° to 60°C
Calculate Frequency Accuracy
You can calculate frequency accuracy in totalizer mode for:
 Frequency Period
 Speed
 Frequency average
Frequency Period
For frequency period, you must know:
 User-defined sample time period (T
s
)
 Application frequency (F
in
)
 Number of accumulated counts in sample time (Counts)