The Secret Of Getting Rid Of Noise On Your Analog Signal

In industrial environments, we often get noise on the analog signal input to PLCs or other controllers. Motors, lousy wiring, etc., can generate noise.

Placing a 1- 100 uF capacitor on the input signal and ground (common to the cabinet)  will reduce the noise the input receives.

If you have any questions or need further information, please contact me.
Thank you,

If you’re like most of my readers, you’re committed to learning about technology. Numbering systems used in PLCs are not challenging to learn and understand. We will walk through the numbering systems used in PLCs. This includes Bits, Decimals, Hexadecimal, ASCII, and Floating Points.

To get this free article, subscribe to my free email newsletter.

Use the information to inform other people how numbering systems work. Sign up now.

The ‘Robust Data Logging for Free’ eBook is also available as a free download. The link is included when you subscribe to ACC Automation.

5 thoughts on “The Secret Of Getting Rid Of Noise On Your Analog Signal”

  1. Hi… Garry
    Whether we have to use capacitor in parallel with analog sensor?

    Is it possible to use twisted wire for analog input instead of capacitor?


    • Hi Abdul,
      Twisted wire is a good idea for external noise along the path. Depending on the type of noise it will cancel it out due to the twisting of the wire. The capacitor will also try to filter this noise out in a more progressive manner. Try the circuit without and with the capacitor to see a difference.

  2. How about for thermocouple inputs? Put the cap between the legs of the input or just the positive to ground? I think the second, but since both legs make the input, maybe one cap on each leg?


Leave a Comment