Rockwell Automation 1756-CFM ControlLogix Configurable Flowmeter Module - Manual (Page 46)

46 Rockwell Automation Publication 1756-UM010B-EN-P - December 2011
46 Configurable Flowmeter Module Features and Operational Modes
Total Overspeed
Use Total Overspeed to monitor when a flowmeter exceeds the Highest
Allowed Frequency. With this feature, the CFM module calculates speed by the
number of pulses counted in a user-defined sampling period. When the speed
exceeds Highest Allowed Frequency, and the Overspeed Alarm is enabled, the
Overspeed Alarm is set.
Total Acceleration
Use Total Acceleration to monitor when a flowmeter exceeds the maximum
acceleration rate. The acceleration rate is calculated by using a three-point
difference formula with unevenly spaced points. The acceleration calculation
indicates the number of samples used in the calculation.
Prover Total
Use Prover Total to monitor the raw counts received during the Prover
portion of the cycle. The Prover Total represents a net total count value
obtained by applying a K-factor and CCF or AGA 7 compensation to the raw
count.
Total Counts
Use Total Counts to monitor the total number of counts the CFM module has
received since it was last reset to zero.
Frequency Average
Use Frequency Average when Frequency Period must be averaged over
multiple samples (meter samples). You must configure the CFM module with a
user-defined number of Meter Samples to use this feature. This uses the total
counts over the total time per a user-defined number of meter samples. (A
meter sample is approximately 20.0 ms.)