Re: [CAD_CAM_EDM_DRO] Re: VISUAL BASIC & CNC

On Sat, 12 Apr 2003 21:57:04 -0000, you wrote:

>So how come some PLC manufatures and other automation companies run
>their system on windows?

I don't know, but I'd personally have a network of interlocked
processors working from a master list. Easy to do with single chip
processors. Or, you can have one processor and have it synchronize
everything. That way, Windows is downloading high level commands, and
it's up to something that has less on its mind to synchronize
everything.

> I am wondering how printers works since they
>never loose step when printing documents..

They get the equivalent, either a line of dots, or a line of
characters, or a complete page image that they convert into dots
(laser printer).

Harvey

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