Re: [CAD_CAM_EDM_DRO] Parallel port interface for pulse Encoder

Dear john,
kindly note that the 2085 pulse per second is the pulse rate that reaches the parallel port finally,(i read it by an oscilloscope)
and i save it to a file,i use C language under DOS(for faster response as DOS is a single task operating system)

i use inportb to read ,so can you tell me where the problem is?

Regards,
Hesham
Jon Elson <elson@...> wrote:
heshammm2003 wrote:

> Dear all,
>
> first let me say hi to all the members,
> kindly if any one can help me abount readind a pulse encoder that sends
> 2085 pulses per second square wave TTL voltage level, the port couldnt
> read the data at that rate even using C lanuage under DOS
> can any body help?

What rate is the C program reading the port? What port pins are
you connecting this to? Did you check the voltage levels out of
the encoder? It may require pull-up resistors to +5 V if the
encoder outputs are open-collector.

You say "couldnt read the data at that rate", but you don't say
how fast the encoder was turning. At 60 RPM, the encoder would
produce, I think, 8340 counts per second. Even a 486 CPU could
read that fast enough, but not if you have a print statement
every read. The screen update is really slow on PCs because it
has to copy the whole screen up to scroll, pixel by pixel.

Jon





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