Re: DRO

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Drew Reynolds" <a_reynolds65@...> wrote:

>
> Hi new to the site and was wandering if anybody has a good source for adding a dro to a lathe/mill using an old laptop and salvaged encoders...
>
> Many Thanks..
>

There are several ways to do that but some of the easiest won't work with a USB connection. You have to read and decode two inputs for each encoder, so a 3 axis unit it takes 6 inputs. They need to be pretty fast inputs if you want the display to keep up with the machine position while you are moving it.

MACH3 will let you read and display encoder inputs. If you don't use it to run code (aka as a CNC controller) then the free demo will work. You have to get at least 6 inputs for the encoder channels (for 3 axis). The cheapest input device for MACH is the humble parallel port and if you use it as a PORT2 since you don't need a bunch of outputs, you can have 12 inputs, all high speed. Of course not a lot of laptops have parallel ports so using it will present more challenges.

You can get I/O devices for MACH that will work with USB. Since you don't need step & dir outputs you don't need a USB card that has the outputs like the Smooth Stepper card. Mesa sells some interesting I/O cards that might work for you.

There used to be a DRO program for a PC but I think it ran under DOS and that is harder to find than a parallel port!

Then there is EMC2 that will have thee same limitations as MACH as far as the parellel port but the MESA works for that too.

In either case (MACH or EMC2) you have the option to "paint" your own screens and make as many DRO's and as big as you want.

Who knows...maybe you will decide to come over to the Dark Side and convert the machine to CNC (:-)

TOM CAUDLE
WWW.CandCNC.com