6. Function blocks6.1 Manufacturer function blocks6.1.2.2 CF - Frequency countereasyE4 base devices provide 4 frequency countersCF01…CF04. These high-speed frequency counters are intern-ally connected with the digital inputs I01…I04 and operate inde-pendently of the cycle time. The contacts will switch accordingto the actual value.Operating principleFor the entire configured measuring interval, the pulses at the input are counted inde-pendently of the cycle time and are then used to determine the frequency. The numberof pulses counted within the measuring interval is then provided as a value at functionblock output QV. Finally, as a result, output QF delivers a value equal to ten times the fre-quency so that the measurement can be accurate to the decimal place despite the factthat the value range is of type integer.This means that the frequency is the value at QF multiplied by 0.1.F= QF*0,1The CF01…CF04 frequency counters are not dependent on the cycle time.The minimum counter frequency is 4 Hz.The maximum counter frequency is 5 kHz.Only square wave signals are permissible.The mark-to-space ratio is 1:1.The counter wiring must observe the following digital input assignment:l I01 counter input for frequency counter CF01l I02 counter input for counter CF02l I03 counter input for counter CF03l I04 counter input for counter CF04NOTICEAvoid unforeseeable switching states.Switch C, CF, CH, CI function blocks only at one single point in the pro-gram.Otherwise, previous counts will be overwritten.224 easyE4 11/18 MN050009 EN www.eaton.com
