Re: VISUAL BASIC & CNC

Luis,

Short answer: no

Long answer: Controlling steppers requires a steady pulse source at a
high frequency. Under Windows this is simply not possible (even with
a realtime priority thread and a multiprocessor system). While you
may be able to get it to move at slow speeds, with some degree of
success, the moment you try and go faster Windows will snatch a few
milliseconds here, and a few there - your motor will be racing along
with intertia and will fly through steps, and you'll lose your
position. If you go REAL slow, you might be okay..

My advice? Get yourself a midware device - something that hooks onto
serial, or that gives you a card. This way your windows program just
sends commands to the card/controller at its leisure and the
controller works to deliver solid steps. There is a project out there
that uses a "dumb" DOS PC to control a stepper setup - the controller
PC (running windows) is connected to this via serial, and the dumb-
box is connected to the stepper board via parallel.





--- In CAD_CAM_EDM_DRO@yahoogroups.com, "luisguillermo98"
<luisguillermo98@y...> wrote:

> Hi group,
> My projects includes a controller, sensor switches, valve and
> steppers. I am wondering how to write program in visual basic
> (using .DLL to controll paralel port in c language) to move the
> stepper without loosing step. I heard that pulse are not sent
> properly in a windows enviroment and that is why most CNC programs
> are writen in DOS or linux to prevent this but I need to run my
> applications in a windows enviroment so my question is how can the
> pulse or signal can be send properly or rechecked to the parallel
> port so stepper motors can run smoothly without loosing steps?
>
> luis..