5 Function blocks
5.7 CF, frequency counter
168
Control Relay easy800
11/11 MN04902001Z-EN
www.eaton.com
Function of the function block
The first measurement is carried out when the function block is enabled via
the signal at CF..EN. The value is output after the gate time (t
g
) has timed
out. The contacts are set in accordance with the measured frequency.
If the CF..EN enable signal is removed, the output value is set to zero.
The pulses on the input are counted for one second irrespective of the cycle
time, and the frequency is determined. The measurement result is provided
at the function block output CF..QV.
Figure 115:Signal diagram of frequency counter
1: Counter input I1 to I4.
2: Upper setpoint value >SH
3: Lower setpoint value >SL
4: Enable CF..EN
5: Contact (N/O) CF..OF: Upper setpoint value exceeded
6: Contact (N/O) CF..FB: Lower setpoint value undershot
7: Actual value equal to zero CF..ZE
Memory
40 + per
4 Byte/Constant at function block input
Cycle time [
μ
s]
easy800 standard
easy800-SWD
30
8
1
2
3
4
t
g
t
g
t
g
t
g
t
g
t
g
t
g
t
g
5
6
7