Re: [CAD_CAM_EDM_DRO] Re: Modular 3, 4-axis Bi-polar Chopper Driver Help

On Sun, 15 Jun 2003 01:40:13 -0000, you wrote:

>First off I would like to thank you for the thorough response;
>it's great to finally find a place that people actually answer
>questions. I still haven't made my mind up whether or not to
>build this board; I have a couple more questions.
>
>1.) On Steve's board schematic for the drive it says "When using
>more than one board remove r10 and link c14 on additional boards."
>Then right below it, it says "Also link sync pins", could someone
>explain this?

If you are using an L297 chip, or this is similar, there's a phrase in
the ap note that says: R10 and C14 determine the chopper frequency.
To reduce noise in a multiple board setup (because the chips are
switching at different frequencies), ground the oscillator pin (short
out c14) on all but one of the chips and tie the sync pins on the
chips together.

That way, the one chip oscillator (for the chopper) will drive all the
other oscillators. All the noise will happen at the same time...

I just designed and built a board with the L297/L298 chip set, and
went through the application notes..... that's what I remember.

>2.) What is Rx1? It says it's optional and it's only required if off
>board current control signal?

Don't know without the schematic.

Hope this helps...

Harvey

>
>Thanks
>
>