EMI Filter Design

Thread Starter


Joined Apr 22, 2023
Hello Everyone,
We are designing a PLC for an industrial automation application.
The PLC takes in input from a general purpose industrial 24VDC Power Supply (which is not in scope of our supply ).
The Power Supply could be industrial grade or not, could be EMI/EMC Compliant or not and the output of the Power Supply could be filtered, regulated, absorb surge or not. In such a condition, what sort of protection should we provide at the input side of our circuit. The input then drives a DC-DC converted which is designed as per TI schematic reference. However, the 24VDC input would also be used for driving IOs of the power supply with the help of a ADR74413r.
Can someone please recommend an input side circuit, which shall convert unfiltered 24VDC to filtered 24VDC supply, including something for ESD, EFT & transient surge protection (including those in typical industrial environment ).


Joined Jan 23, 2018
Some PLCs will accept whatever power source is used, if the voltage is correct. Others will not.
As for powering the I/O, what is that device, the ADR74413r?? I am not going to research it at all, the TS can explain what it is intended to do. Most industrial PLC I/O that is intended for 24 volt DC operation will perform very well with a DC supply that is fairly stable and adequately rated for the intended loads.
So the answers depend on which brand of PLC is involved.