Emerson Micro Motion 2700 Configuration And Use Manual page 36

Configure process measurement
Procedure
Set Mass Flow Cutoff to the value you want to use.
The default value for Mass Flow Cutoff is 0.0 g/sec or a sensor-specific value set at the
factory. The recommended setting is 0.05% of the sensor's rated maximum flow rate or a
value below the highest expected flow rate. Do not set Mass Flow Cutoff to 0.0 g/sec.
Effect of Mass Flow Cutoff on volume measurement
Mass Flow Cutoff does not affect volume measurement. Volume data is calculated from the
actual mass data rather than the reported value.
Interaction between Mass Flow Cutoff and AO Cutoff
Mass Flow Cutoff defines the lowest mass flow value that the transmitter will report as
measured. AO Cutoff defines the lowest flow rate that will be reported via the mA output. If
mA Output Process Variable is set to Mass Flow Rate, the mass flow rate reported via the mA
output is controlled by the higher of the two cutoff values.
Mass Flow Cutoff affects all reported values and values used in other transmitter behavior
(e.g., events defined on mass flow).
AO Cutoff affects only mass flow values reported via the mA output.
Example: Cutoff interaction with AO Cutoff lower than Mass Flow Cutoff
Configuration:
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•
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•
Result: If the mass flow rate drops below 15 g/sec, mass flow will be reported as 0, and 0
will be used in all internal processing.
Example: Cutoff interaction with AO Cutoff higher than Mass Flow Cutoff
Configuration:
•
•
•
•
Result:
•
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mA Output Process Variable: Mass Flow Rate
Frequency Output Process Variable: Mass Flow Rate
AO Cutoff: 10 g/sec
Mass Flow Cutoff: 15 g/sec
mA Output Process Variable: Mass Flow Rate
Frequency Output Process Variable: Mass Flow Rate
AO Cutoff: 15 g/sec
Mass Flow Cutoff: 10 g/sec
If the mass flow rate drops below 15 g/sec but not below 10 g/sec:
- The mA output will report zero flow.
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Micro Motion Model 2700 Transmitters with Analog Outputs