Re: Parallel Port Pins

Have you tried TurboCNC? It is shareware ($20 for registration which
gives you the source code too).

Frank

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Brad Woolley <brad@r...>
wrote:

> Hi,
>
> Thanks Alan,Tim and others, I think I am getting it now,

although

> now I have the thing up and running I am getting a constant pulse

approx 1

> per second on all my parallel pins this is confusing the

controller, as this

> pulse is there all the time I suspect my machine, I'll have to dig

further.

>
> I am not getting much help with KCam, can anyone recommend a

free /

> cheap software similar to KCam to use ?.
>
>
> Cheers
>
> Brad
>
> -----Original Message-----
> From: Alan Marconett KM6VV [mailto:KM6VV@a...]
> Sent: 16 June 2003 10:58 PM
> To: CAD_CAM_EDM_DRO@yahoogroups.com
> Subject: Re: [CAD_CAM_EDM_DRO] Parallel Port Pins
>
>
> Hi Brad,
>
> For most controller programs, the step pulse has a short duration
> (usually active low), that will be generated at a specific rate

dictated

> by the number of steps/inch and the feed rate wanted. The number of
> steps issued is calculated from the distance the axis is to travel,

and

> the steps/inch of the hardware (mill/motor/leadscrew).
>
> This pulse "stream" from the parallel port "step" pin will also

probably

> start off fairly slow, and accelerate to the feed rate, and then
> decelerate, finally stopping when the required number of pulses have
> been generated.
>
> The pulse width is determined by the software, and must meet the
> requirements of the stepper driver (hardware). Often about 10uS in
> length. The direction pin will be set high or low, depending on the
> direction of the move.
>
> Simply stated, the driver makes the stepper take a step for

each "step

> command" it receives from the controller program. (Microstepping

may

> cause the drive to actually take "baby steps" for each commanded

step).

>
> The data sheets for the driver hardware will usually define the

step and

> direction signals required of the controller software.
>
> HTH
>
> Alan KM6VV
>
>
> Brad Woolley wrote:
> >
> > Hi,
> >
> > I'm still a little confused with the output from a

parallel port

> > (KCam, but I'm sure others are the same), looking at one axis, I

see the

> > three pins Pulse, Direction and Enable, Direction is pretty

obvious on or

> > off indicating forward or reverse, I assume the enable indicates

that the

> > motor is to be activated, but what information does the pulse

give me, is

> it
> > simply counting the pulses while the enable bit is set, or is

there some

> > form of bit conversion to give me a number, either way how do I

know the

> > pulse width etc.
> >
> > Can anyone point me in the direction of somewhere to

explain this,

> I
> > have searched the internet without any success in finding an

explanation.

> >
> > Thanks in advance.
> >
> > Brad
>
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