Re: [CAD_CAM_EDM_DRO] Parallel port interface for pulse Encoder

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