The output frequency of the inverter refers to the actual operating time of the numerical value, often with a given frequency signal or a little difference, need to be measured for our reference in order to facilitate feedback regulation, if the difference is large to detect a given source and load motor and other devices. Then how to detect the actual output frequency of the inverter, there are many common methods is to use the analog output signal and communication of the inverter given.

1. Analog mode, we know that the inverter has analog input and output part, which analog input for a given frequency, such as 0 -10 V DC voltage signal and 0 -20 ma current signal; Analog output is to detect the state of the inverter, such as operating voltage, operating current, power and we want to detect the frequency value can be given in the form of analog. The same output form has voltage signal and current signal, this output parameter we can choose in the frequency converter settings, common detection devices are: 1 ammeter voltmeter direct measurement based on the table to calculate the value of the actual operating frequency, 2 is digital display such as tachometer analog to digital display more convenient, 3 is the AD module and PLC for the acquisition of analog quantities into digital quantities for feedback control. In fact, their principle is the same, is the analog to the actual frequency value, such as 10 V voltage signal corresponding to the maximum value of 50 Hz, in accordance with the scale of conversion can be, if 2.5 V corresponding to the output frequency of the inverter is 12.5 Hz.

2. Communication mode, this is relatively difficult but relatively simple wiring data acquisition more convenient do not have to convert. Now the inverter basically supports communication mode to control, we can not only use it to control the operation of the inverter, such as frequency given, positive and negative, but also can real-time acquisition of operation, all data send and receive are completed through several cables, the operation is also the corresponding command can be sent. The common communication mode is Modbus, which is an economical and general-purpose converter, and PROFIBUS communication, PROFINET communication, Ethercat communication, etc. . We can directly use these communication methods to complete the acquisition of operating frequency. The specific method should be based on the frequency converter to support the communication format and host computer to decide.

Source: internet (for study only, intrusion and deletion)