Re: servo driver on a chip ?

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Dennis Schmitz"
<denschmitz@...> wrote:

>
> It might be totally different inside, but it still performs the same
> function, taking command input and controlling something based on it.

I think the general concept of a close loop would fit both. the
difference being the type of sensors. Although I don't think there is
a specific requirement for any type of sensor, the R/C servos would
not require anything that might be unlimited. whereas a
MotionControl Servo certainly would find it hard to use a fixed range
device like a pot. The main difference being that the R/C unit might
not have to make a full revolution, whereas the MC applicion offen has
many hundreds of revolutions.

But the concept of monitoring the error and correcting for that would
be common to both.

> It's just a different command format. A servo could just as easily
> take a command as an analog signal input or a byte code, or even a
> complex command sequence specifying position, speed, acceleration, and
> timing profile for the movement.
>
> This is probably out of context here, though (although not necessarily
> off-topic). This industry is used to the step/direction command
> format, but that's certainly not the only way to get things done (or
> the best one). With a rich command format, you can reduce the load on
> the main computer as well as receive fault codes from the servos.

I think the whole concept of a serial command vs. parrallel commands
is being used in more than a few devices.

The idea is to be able to use a driver with something like Mach3 that
does output a step and direction signal.

As I understand, allegro and Sanken as well as some others put
complete circutis on a chip. Allegro puts a stepper driver on a chip.

At some point someone should put a quadrature interface on a chip as
well as a motor controller to make a single chip device that would run
the items necessary to make a MC servo on a chip.

MicroChip does have an application bulletin that gives all the details
to put all the bits together to make a stepper drive on a PIC.

And, putting the whole thing in software would be fine as well.

So, I guess that is the real question. Is there a means of putting
together a motion control servo driver ?

Dave