(VFD, PLC, HMI) Filter

MICNO filter is an HMI filter for inverter used to eliminate interfering noise, filtering the input or output to obtain a pure power supply.

The PLC filter can effectively filter out frequencies at a particular frequency or frequencies outside of that frequency.

What is a filter for inverter?

The filter for inverter is used to limit the rate of rising of the inverter output voltage and reduce common mode noise to the motor. In typical applications where DV/DT is limited to 100-500 V//spl mu/s, the  resonance frequency of the filter is higher than the switching frequency.

Working Principle of VFD HMI Filter

HMI controls are connected with filters in the standard data-flow way: through input and output ports.

There are three possible ways of VFD HMI filter connection:

From a filter’s output to a control’s input – e.g. for displaying an image or a text result.

From a control’s output to a filter’s input, as data sources – e.g. for setting various parameters in a program with track-bars or check-boxes.

From a control’s output to a filter’s input, as events – e.g. for signaling that a button has been clicked.