Emerson Micro Motion 5700 Configuration And Use Manual page 139

Calculate frequency from flow rate
The Frequency=Flow option is used to customize the frequency output for your application
when you do not know appropriate values for Units/Pulse or Pulses/Unit.
If you specify Frequency=Flow, you must provide values for Rate Factor and Frequency
Factor:
Rate Factor
Frequency
Factor
The resulting Frequency Factor must be within the range of the frequency output ( :
•
•
Tip
If Frequency Output Scale Method is set to Frequency=Flow, and Frequency Output Maximum Pulse
Width is set to a non-zero value, set Frequency Factor to a value below 200 Hz.
Example: Configure Frequency=Flow
You want the frequency output to report all flow rates up to 2000 kg/min.
The frequency receiving device is configured for 10 pulses/kg.
Solution:
Set parameters as follows:
•
•
Configuration and Use Manual
The maximum flow rate that you want the frequency output to report.
A value calculated as follows:
FrequencyFactor =
where:
T Factor to convert selected time base to seconds
N Number of pulses per flow unit, as configured in the receiving
device
If Frequency Factor is less than1 Hz, reconfigure the receiving device for a higher
pulses/unit setting.
If Frequency Factor is greater than 10,000 Hz, reconfigure the receiving device for a
lower pulses/unit setting.
FrequencyFactor =
FrequencyFactor =
FrequencyFactor =
Rate Factor: 2000
Frequency Factor: 333.33
Integrate the meter with the control system
RateFactor
x N
T
RateFactor
x N
T
2000
x 10
60
333.33
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