Rockwell Automation 1760-xxxx Pico GFX-70 Controllers User Manual - Manual (Page 185)

Publication 1760-UM002B-EN-P - March 2005
Wiring with Pico GFX-70 4-75
Frequency Counters
Pico GFX-70 provides four frequency counters which are CF01 to CF04. The
frequency counters can be used for measuring frequencies. You can enter
upper and lower threshold values as comparison values. The high-speed
frequency counters are hard wired to the digital inputs I1 to I4.
The CF.. frequency counters operate independently of the cycle time.
Counter Frequency and Pulse Shape
The maximum counter frequency is 3 kHz.
The minimum counter frequency is 4 Hz.
The signals must be square waves. The mark-to-space ratio is 1:1.
Measurement Method
The pulses on the input are counted for one second irrespective of the cycle
time, and the frequency is determined. The result of the measurement is made
available as a value to the function block output CF..QV.
Wiring of a Counter
The following assignment of the digital inputs apply.
• I1 counter input for the counter CF01
• I2 counter input for the counter CF02
• I3 counter input for the counter CF03
• I4 counter input for the counter CF04