Re: [CAD_CAM_EDM_DRO] Mach2 and parallel port cards - Dave

>>>While the PC will handle at least 3 parallel

ports I don't think MACH 2 will do more than 2. There might be an
issue with having to read all of those port pins every few
milliseconds that is a limiting factor. Art can confirm/deny that

Consider it confirmed. Mach2 will only read 2 ports maximum. The ports are
read not every few milliseconds, but every 22 uSeconds. ( and a very
reliable 22uSeconds...) Unfortunately, they seem to have a 1uSecond
readtime, which means the 2 port reads and 2 port writes required take
4uSeconds, which is the only reason Mach2 is limited to 45000 interrupts per
second. I hear though, that Indexer does 100,000 per second. If this is
true, then I may be able, when I have time to do the research, to either add
a third port or up the speed even further. But at the moment, 45000 seems to
please most people so I haven't worried about it..

Thanks,
Art
www.artofcnc.ca