Re: ethernet flaky with servos?

["Pete Cook" <kf2qd-at-terraworld.net>]

I have some related expirience - I work for a company that build plasma &
oxy/Fuel cutting machines - We use a 3com 10baseFL fiber NIC for the same
reason - One customer thought they knew better and tried to use 10baseT
instead and watched their whole network turn to molasses. You might check
the grounding of all components in you system. Ground the machine, the
motors, all encoder cables to an outside ground rod. What may be happening
is that there is enough noise generated and the only ground path is through
the computer and thus everything attached to that computer is also having to
deal with noise. Also check the routing of all your cables and make sure
that the motor cables (including the AC Supply) are run seperate from any
computer connected cabling. We have also had serial ports on the computer
used to download programs to the cutting machine damaged - we switched to
fiberoptic modems to isolate the serial ports on the cutting machine and
computer.

Pete Cook

PS - if you are using PWM type drives they are extremely noisy and need
extremely good grounding and isolation.
>
> Hello All -
> I have a difficult that's not quite on the main topic
> of this list.
>   When my motors are on and holding position,
> my local ethernet segment goes to heck.  Not just the
> test machine, but everything attached to the switch.  When
> the motors are on, but idling, I see some network errors, but
> it is still usable.  I have a linksys 8-port workgroup switch
> and UTP cat5 cabling.  The motors have no load - bench
> system - and the drives and motors are in a steel shelf.
> Would STP cabling or gobs of shielding be useful?
> Has anyone had similar experiences?
> Thank you.  --krb
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