Rockwell Automation 1756-CFM ControlLogix Configurable Flowmeter Module User Manual

Page 55

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55

Rockwell Automation Publication 1756-UM010B-EN-P - December 2011

Configurable Flowmeter Module Features and Operational Modes 55

Fill Total

Use Fill Total to determine the current total in an ongoing fill application.
During the fill cycle, use Net Volume to check the Fill Total.

Total Counts

Use Total Counts for the accumulated raw counts the CFM module has
received since its last reset. The total counts may be used for applications that
employ a different methodology to calculate Gross and Net Volumes.

Gross Volume

Use Gross Volume to convert total counts to volumetric units. The module
employs a user-defined K-factor in the conversion. For example, you can
configure the CFM module so that 4 counts = 1 pint. A meter factor is also
available for calibration.

Net Volume

Use Net Volume to apply a user-defined compensation factor (i.e. AGA 7 or
Logix compensation) to the Gross Volume. This feature uses the following
equation:

Gross Rate

Use Gross Rate to convert total counts to rate units. The module employs a
user-defined K-factor in the conversion. The K-factor is a divisor, and the time
interval is divided by this number, as shown below.

 If the input frequency is below 100Hz, the K-factor used is always 10.0

for frequencies interpolated between 0-100Hz.

Net Volume =

Total Counts in Meter Sample

K-factor

x Meter Factor x CCF

Gross Rate =

Total Counts in Meter Sample

K-factor

x Meter Factor

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