Minimizing Noise on Your Servo System
Posted by Michael Norman on Fri, Aug 21, 2009 @ 12:05 PM
Your servo suffers from intermittent failure, feedback loss,
runs choppy, or trips out on some sort of encoder error. Could electrical noise
be the culprit?
Electrical noise is present in every electrical system. It
can disrupt the feedback signals (especially with resolvers) on the motor and
cause the drive to misread information and not perform as instructed. Noise is
a little thought, high impact problem that is relatively easy to minimize.
Cable selection is crucial.
Try to buy cable with the correct number of wires. Use twisted pairs for the send and return of
each circuit if possible. Keep your
cables as short as possible, and do not just coil up the extra cable and leave it
in a cabinet.
Use shielded cabling always. Just having a shield inside the cable is not enough; it
needs to be properly grounded at either the motor or the drive but not both. Shielded cabling can actually make your
problem worse if you do not have a solid ground.
Keep feedback cables from looping
around or running closely parallel to high voltage cables. Maximizing distance between communication and
high voltage cabling will minimize the impact of noise on your system.
Motors/Drives/Encoders are often misdiagnosed as bad when
they are really just being affected by noise.
Minimizing noise will save you downtime and unnecessary repair costs.