Re: [CAD_CAM_EDM_DRO] steppers+feedback+emc

EMC does have a module that drives closed loop stepper. It is designed to
take the encoder feedback through the DRO card that is sold by Camtronics.
With that said if you are having a problem with missed steps during normal
use the closed loop stepper is not likely to solve the problem. You would
normally get a lost step if you are asking the motor to take a step when it
is out of torque at the given RPM. What the closed loop will do is command
another step on top of the current steps to try and catch up. That is
actually asking for more RPM than you are already capable of which is a
recipe for more lost steps and then the cycle repeats.

I think you need to determine why you are losing steps and fix the problem
there.

Tim
[Denver, CO]

----- Original Message -----
>
> after milling some mdf with a stepper controlled table I think i need
> to add feedback(encoders) to eliminate missed steps...
>
> my question is:
>
> would it be possible to hook up the encoders directly to the pc and
> let EMC read them and act accordingly, ie. implement a PID controller
> in (real-time) software ?
> the parallell port pins won't be enough(?), but what other options
> are available ? (serial?)
>
> also, a question for EMC users: how does PC speed affect the speed at
> wich you can do interpolated(linear, cubic etc.) runs on a mill?
>
> thanx for any answers.
>
>
>
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