Rockwell Automation 1771-CFM,D17716.5.99 CONFIGURABLE FLOWMET - Manual (Page 45)

4–11 Configure the CFM Module
Publication 1771Ć6.5.99 - December 1995
HighĆresolution Frequency Mode
This mode measures incoming pulses over a user-specified time
interval (4-1000ms) or over a user-specified number of input
signal pulses. In this mode, the CFM module calculates:
•
rate of input (0-100,000Hz)
•
acceleration value
BTR status and input data
1771ĆCFM
F0
G0
F1
G1
not used
input
device
not used
not used
BTW configuration
PLC processor
uses channels 0&1 or 2&3
Frequency Sampling
In the High-resolution Frequency mode, frequency sampling begins
on the leading edge of the first pulse to occur and ends on the next
pulse to occur after the sampling time has expired or after the
user-specified number of pulses has occurred. In this mode, the CFM
module calculates frequency based on values you enter in the BTW
configuration block.
Use this mode if you:
• need accurate frequency value
(see page A-1 for frequency accuracy)
• need fastest possible sample
update time across large
frequency range
• want to calculate acceleration
• need to measure frequency in 10ths of Hz
(0.1Hz)
Typical application:
turbine generators