Rockwell Automation 1756-CFM ControlLogix Configurable Flowmeter Module - Manual (Page 47)

47 Rockwell Automation Publication 1756-UM010B-EN-P - December 2011
Configurable Flowmeter Module Features and Operational Modes 47
Frequency Period
Use Frequency Period to determine the frequency over a user-defined sample
time.
Speed
To use the Speed feature, you must set a resolution. The module uses the
resolution to determine the number of counts used in the Speed calculation.
For example, if you set the resolution at 0.00001, the module requires 100,000
counts. In this case, the module examines the previous samples stored in its
buffers until 100,000 counts are found. The counts are divided by the time it
took to accumulate them and the resulting value is the module speed.
Acceleration
Use Acceleration to determine an acceleration value over a user-defined
number of samples.
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. The module can then
convert the total number of counts received to a total number of pints.
Net Volume
The Net Volume value represents the Gross Volume value with a AGA 7 or
Logix compensation applied. This value is calculated at an application’s base
(i.e. standard) operating conditions.