Rockwell Automation 1771-CFM,D17716.5.99 CONFIGURABLE FLOWMET - Manual (Page 46)

4–12 Configure the CFM Module
Publication 1771Ć6.5.99 - December 1995
You can specify these values:
Value BTW word # Use to
Minimum Frequency Sampling Time ➀ 6, 16, 26, 36
specify the minimum time the CFM module will spend collecting
pulses to determine a frequency. The sample begins on the
leading edge of a pulse.
Sampling Termination 5, 15, 25, 35 (bit 13)
terminate the sampling on either a time base or a set number of
pulses, depending on which occurs first.
Bandwidth Limit 5, 15, 25, 35 (bit 14)
control the maximum time the CFM module spends calculating
a frequency and the minimum frequency that can be read by
the CFM module.
Acceleration Calculation Time 5, 15, 25, 35 (bits 00Ć09)
specify the number of frequency samples the CFM module will
spend to calculate the acceleration value. The default value (0)
will calculate a rolling average of the previous five samples.
Since the actual frequency sample time can vary, so does the
Acceleration Calculation Time.
Acceleration Alarm 9, 19, 29, 39
determine the acceleration value that, if exceeded, will activate
the BTR Acceleration Alarm (word 4 & 5, bits 00 & 08).
RANGE: 0Ć32,767
The CFM module will not calculate an acceleration if this
acceleration value is zero.
Number of Pulses to Terminate Sampling 7, 17, 27, 37
terminate the sampling when the specified number of input
pulses are received.
Highest Allowable Frequency 8, 18, 28, 38
specify the highest frequency value expected on the input
channel. When this value is exceeded, the input channel's
overspeed alarm will activate.
This value is also used in calculating Percent of Full Scale
(BTR word 6, 15, 24 or 33).
Frequency Scaler Multiplier/Divisor 10, 20, 30, 40
scale the returned frequency and acceleration to actual
engineering units.
Frequency Multiplier must be < Frequency Divisor.
For each value RANGE: 1Ć255 DEFAULT: 1
The scaled frequency/acceleration value can not be used to
trigger any outputs (outputs triggered by frequency/acceleration
are triggered by actual frequency/acceleration).
➀ If you are setting this value for both channels (0 & 1 and 2 & 3), the Minimum Frequency Sampling Time for both cannot = 4ms
(one can = 4ms and the other can = 5ms, but both cannot = 4ms).