Re: LM628

Mike Romine wrote:

> But given how fast and cheap the 16 and 32 bit microcontrollers are
> getting now-a-days, I have come to believe closing the loop in firmware
> on a processor is the way to go for a ground up system.
>

I talked to tech80 about the PMD chipset as they also use it. They seemed to prefer the LM628/629
though. In position mode I usually got trajectory updates at several milliseconds but they insist
that < 1 millisecond can be done with their low level routines. I like the 100 microseconds or
so quoted for EMC much better though! Even 1 millisecond at the high feed rates of a cnc router
could result in several thousanths position error in interpolated moves.

Leslie M. Watts
ITW Advanced Technology Center