Emerson Micro Motion 3711, Configuration And Use Manual, Page: 52 / 234

44 Micro Motion
®
Model 3711 Gas Flow Computers
Configuring the Core Interface
Flow calibration values
Two separate values are used to describe flow calibration: a 6-character FCF value and a 4-character
FT value. Both values contain decimal points. On the sensor tags, these two values are concatenated
to form a 10-character string called Flow Cal or Flow Cal Factor (see Figure 5-5).
• For the FCF value, enter the first six characters of the string. In the sample tags in Figure 5-5,
this value is shown as
19.000
.
• For the FT value, enter the last four characters of the string. In the sample tags in Figure 5-5,
this value is shown as
5.13
.
5.5.2 Damping
You can configure damping for both mass flow measurement, density measurement, and temperature
measurement. 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.
When you specify a new damping value, it is automatically rounded down to the nearest valid
damping value.
Valid damping values are listed in Table 5-4.
Note: For typical gas applications, Micro Motion recommends a flow damping value of 3.2 (the
default).
5.5.3 Meter factors
Meter factors allow you to adjust the Model 3711’s reported mass flow rate or density value to match
an external measurement standard. Meter factors are used for proving the meter against a Weights &
Measures standard. You may need to calculate and configure the meter factors periodically.
Use the following formula to calculate a meter factor:
Table 5-4 Valid damping values
Process variable Valid damping values
Mass flow 0, .2, .4, .8, ... 51.2
Density 0, .2, .4, .8, ... 51.2
Temperature 0, .6, 1.2, 2.4, 4.8, ... 76.8
NewMeterFactor ConfiguredMeterFactor
ExternalStandard
ActualTransmitterMeasurement
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