Re: [CAD_CAM_EDM_DRO] Re: servo board

george_barr wrote:

>Thanks for replying. My first router/mill will use geckos. In fact,
>I already have 3 geckos for step/direction. However, I would like to
>eventually move into the more professional stuff like servos. I have
>looked at the servotogo, vigproducts.com (cost too much since it
>needs more expansion boards), and pico-systems. I am just stuck
>between the servotogo and pico-systems. I was told that the
>servotogo has an 8 MHZ ISA bus while the pico-sytems uses a fast
>parallel port. I was told that the ISA is a much faster
>communication bus but I am not sure if that translates into better
>performance.
>

The ISA can be a bit faster, really not much with the IEEE-1284 protocol
on the parallel port. It makes no difference in performance as long as the
transactions to do the servo update are completed in time. I have measured
it at 50 uS on a 333 MHz Pentium II, from reading the encoder position,
through the PID calculation to writing out the new velocities.

Jon