Re: [CAD_CAM_EDM_DRO] PWM input Servo Amp / Universal Stepper Controller

k8zre wrote:

>Hello Jon...
>
>Thanx for your input on my servo/driver failure. I will check the
>servo motor to see if might be shorted to ground. I can run the
>motor ccw and cw off of a table top power supply but it sounds rather
>noisey.
>
>I looked at your PWM Servo Amp and see that it has no encoder
>feedback loop. But it appears this is supplied via the Universal
>Stepper Controller card. Can the PWM Servo Amp along with the
>Stepper Controller function stand alone, or does it only work with
>EMC or some other external program??
>

Right now, it only works with EMC. I will have the full details to
program the
controller on my web pages soon, so if anyone wants to write a driver for
other programs, it should be possible. It needs to be a control program
that
understands the servo mode of operation, where the computer reads the
position
from the encoder counter and sends a velocity to the servo amp.

> I do like the over current
>protection feature, having just chewed through 2 Rutex boards (it
>only takes a split second!). I was suprised to learn that neither
>Gecko or Rutex provide this feature.
>
>

Well, it costs extra, but it is worth it. My prototype had a bad solder
joint
that went open at the NAMES show. Without a separate overcurrent detector,
it would have gone up in smoke, too. With it, however, it just went into
shutdown everytime you tried to move that axis.

The Gecko and Rutex drives DO have simple overcurrent protection, but they
don't have a backup to sense fault currents that don't flow out the drive's
ground terminal. They also don't have any internal inductance, so a winding
that has shorted inside the motor will also cause at least the stepper
drive to
go up in smoke. My drives also have a film capacitor on the board so you
don't have to fool with external capacitors to keep the big internal one
from
burning out prematurely.

Jon