Re: parallel port not working with emc?

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "pearcedang" <pearcedang@y...> wrote:

>
> Can EMC redefine the assignments of pins 14,16,17?
>
> The current pin assignments are as Irby indicated for both the
> stepperworld FET-3 board 14,16,17 as x,y and z enables) and for EMC
> (using Freqmod according to the EMC manual 14, 16,17 are unfortunately
> assigned to B step, C dir, C step repsectively).
>
> I wrote to Rustle Laidman of stepperworld and he explained:
> > The (FET-3) axis enable bits are active LO, however pins
> > 14 and 17 are inverted in (the parallel port) hardware,
> > so in software you would set them HI.
> > Another way to think of this is to SET 14,17 HI, and 16 LO to
> > activate all axis.

Hi,

As far as redefining EMC pin assignments, a lot of programmers out there could do that for EMC and recompile the program for you, if some later version EMC can't do it outright. But I would consider making up an "adapter" cable between the parallel port cable and the FET-3 board. One thing I've noticed in playing around with different programs is that the parallel port pin assignments can vary, and an "adapter" cable is pretty simple way to make most any program work with a given controller board.

There are several ways you could go, but one way would be to make up a short cable and connectors to fit between your parallel port cable and the FET-3 board. Run pins 2-7 straight through. If you don't mind having the motors enabled all the time, connect pins 14, 16, and 17 to any pin from 18-25 at the "FET-3" connector and leave pins 14, 16, and 17 unconnected at the "parallel port cable" connector. Pins 18-25 are grounds and FET-3 enable is active LO, so this enables the motors all the time. Optionally, you could put a switch between pins 14, 16, and 17 and ground to allow you to switch "enable" on and off. I don't know offhand if the "enable" lines on the FET-3 board are pulled HI on the board, and the simple switch may not work unless they are.

As far as hooking up limit switches, home switches, etc. I don't know how the FET-3 board handles these, so I can't say what to do with these signals. EMC uses only one pin, 12, for a "home" indication on any of the axes. It uses pin 15 for a "positive" motion direction limit indication on any of the axes, and pin 13 for a "negative" motion direction limit indication on any of the axes.

Hope this helps.
Irby