Howdy.

I am setting up a PC for a Mach machine.  It is for one of my engineering friends (he's the CNC guy, I'm the PC guy).

Does Mach require that the parallel ports have their own interrupt / IRQ?  I read the manual and understand about the I/O addressing, but there is no mention of IRQs.  Maybe I'm just thinking to deep into the old days of important functions like this re

(fat finger disease...)

...like this requiring IRQs.

I'm using SIIG add-in cards:

http://siig.com/product.asp?catid=97&pid=150 (mine are a slightly older version)

Windows XP has both add-in cards (LPT2 and LPT3), as well as the onboard LPT1, set to "Never use an interrupt" in Port Settings.  Is this the correct setting?  Any other settings in here I should know about, or are the defaults generally just fine?  Any motherboard things I should do, like setting specific PCI slots to specific IRQs (always a fun game with XP and modern HALs)?


Two more questions:

1.  Can Mach use 3 parallel ports? The two SIIG PCI cards in addition to the onboard parallel port?  My engineer friend is the type to want more more more  :-)  Not a "must have," just curious.  The manual never expressly states a max.

2.  If it is only 2 parallel ports max, can I set Mach II to use JUST the 2 add-in cards and not the onboard LPT1 at all?  Does the Mach III manual page 5-2 say all there is to say on this subject?    I want to do this in case of accidents so the motherboard is less likely to get nuked.  I am aware of outboard opto-isolator circuits and we're definitely considering them, but just in case.  Also for consistency I'd like the whole thing to go through the same chips. 


I really hope I'm not asking bone-headed questions.  I'm a not-so-hot PC guy with almost zero CNC experience, I've never used your software, and have only read the manual (and a few dozen forum posts) while trying to prepare this PC for my friend.  He's generally brilliant .... just not with PCs!  What a pair we make trying to convert an old Ah-ha milling setup to something more modern.  He's already purchased your product.

Thanks in advance,
Patrick

I have a dual port SIIG card that I use for my machine, I don't have IRQ's assigned to any of the lpt ports, But windows does assign a 'odd' io address that can't be changed, in my case 0xffa8 but I plug that into mach3 and it works fine.. Mach3 doesn't handle 3 lpt ports that I am aware of.

"If it is only 2 parallel ports max, can I set Mach II to use JUST the 2 add-in cards and not the onboard LPT1 at all?  Does the Mach III manual page 5-2 say all there is to say on this subject?"

Yes, just set the port one io to one of the SIIG cards and port 2 to the other io. In my case (Single card dual port) 0xffa0 & 0xffb8
and I use 0x387 for a printer. If can find the IO range assigned to the port under control panel, system, lptX, resource tab.

Bryan

Thanks!  I had a feeling I was over-thinking it.