Re: L297 / L298 Help Required Pls!

John / Rich

Thanks for your reply's!

This is what I have found since the original post...

The stepper driver cards are running at 12V for hi.
On the logic board there are three ILD74's (Dual opto transistors)
these are accepting between 0-3.5V Lo/Hi respectively its set high by
default then pulses down to low (step takes place) then back to hi on
the output side a single pin reads 12V and pulsates down to 0 this is
connected to the stepper drives the DIR side is the same but toggle
between high and low (high = Clockwise).

Does this make any sense?

I presume that when the logic side goes low it sinks the 12V side to
ground via a resister this then produces a low.

Does this sound likely?

TIA
Steve.



--- In CAD_CAM_EDM_DRO@yahoogroups.com, "paragon032003" <sme@p...>
wrote:

> Hello All (Sorry for the post without subject ... Half a sleep

today!)

>
> Could someone please explain how to connect a L297 / L298 Stepper
> driver to the PC parallel port?
>
> The parallel port send Step / Direction info. Hi/Low signals ... on
> two pins.
>
> What I don't understand is how this works and where the GND / + side
> comes from the PC.
>
> Additional info ....
>
> I have three stepper cards that control X ,Y, Z axis of a mill.
> When I use a logic probe on the card connectors I find the step pin

is

> high by default (from the stepper card). When I turn the jog button
> this flashes the Grn (low) led on the probe then returns to high
> (red) and the stepper motor turns.
> This is running on an old machine that would be sent information in
> blocks at a time via an rs232 port.
>
> I am attempting to bypass this logic and go direct to the cards via

a

> PC printer port.
>
> TIA
> Steve