74 Micro Motion
®
Model 2400S Transmitters with Analog Outputs
Optional Configuration
To configure cutoffs:
• Using ProLink II, see Figure C-2.
• Using the Communicator, see Figure C-7.
Note: This functionality is not available via the display menus.
8.4.1 Cutoffs and volume flow
If you are using liquid volume flow units (
Vol Flow Type is set to Liquid):
• The density cutoff is applied to the volume flow calculation. Accordingly, if the density drops
below its configured cutoff value, the volume flow rate will go to zero.
• The mass flow cutoff is not applied to the volume flow calculation. Even if the mass flow
drops below the cutoff, and therefore the mass flow indicators go to zero, the volume flow rate
will be calculated from the actual mass flow process variable.
If you are using gas standard volume flow units (
Vol Flow Type is set to Std Gas Volume), neither
the mass flow cutoff nor the density cutoff is applied to the volume flow calculation.
8.4.2 Interaction with the AO cutoff
The mA output has a cutoff called the AO cutoff. If the mA output is configured for mass flow,
volume flow, or gas standard volume flow:
• And the AO cutoff is set to a greater value than the mass, volume, or gas standard volume
cutoff, the mA output will report zero flow when the AO cutoff is reached.
• And the AO cutoff is set to a lower value than the mass, volume, or gas standard volume
cutoff, when the mass, volume, or gas standard volume cutoff is reached, all outputs
representing that process variable will report zero flow.
See Section 6.5.3 for more information on the AO cutoff.
8.5 Configuring the damping values
A damping value is a period of time, in seconds, over which the process variable value will change to
reflect 63% of the change in the actual process. Damping helps the transmitter smooth out small,
rapid measurement fluctuations.
• A high damping value makes the output appear to be smoother because the output must change
slowly.
• A low damping value makes the output appear to be more erratic because the output changes
more quickly.
Damping can be configured for flow, density, and temperature.
Table 8-2 Cutoff default values
Cutoff type Default Comments
Mass flow 0.0 g/s Recommended setting: 5% of the sensor’s rated maximum flowrate
Volume flow 0.0 L/s Limit: the sensor’s flow calibration factor, in units of L/s, multiplied by 0.2
Gas standard volume
flow
0.0 No limit
Density 0.2 g/cm
3
Range: 0.0–0.5 g/cm
3
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