Originally Posted by
marq_torque
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Also my encoder supplier suggested to run -A and -B through whole length of cable and ground them to power supply of encoders.
Why would you ground the A/ & B/ of the encoders? These transition between 0 and 5v with respect to common just as the A & B do.
This would essentially short the complements to ground.
Originally Posted by
marq_torque
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Was thinking that computer's earth terminal and Vfd's Earth are going to same supply common that's why giving the noise!!!
I would suspect that the common grounding is insufficient if anything, you need to take the PC P.S. common and all shields and encoder power supply common to a central point including the service ground.
Have you also bonded the VFD and motor frame to the star point ground?
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.