Mac Intel chips for CNC - or > USB/serial/parallel converters anyone ?

[nick mulder]

Hi,

I'm a mac user as it has suited most of the work I have done in the past - I'm keen to develop a motion control system that uses very similar elements to many CNC systems ...

Turns out to prototype the system I need to convert a mill to CNC anyway, however all the freeware and pro g-code and similar system utilize the parallel or serial port to talk to the steppers/servos and associated drivers

I was about to purchase a PC but now I have discovered that it is now possible to run XP on the mac and indeed saw one in action in store today. This is not a virtual simulation, it runs natively, I think even linux is go on the new chips

Upon asking the guy in the store if there was such a thing as USB serial and parallel converters he told me 'no' ... a quick search on google gave me myriad results for many examples seems like every man and his dog have made a copy of the same product and I'm keen to attempt a reverse engineer meself...

>> question is tho:

has anyone tried a setup such as this - a mac running XP talking to CNC drivers like say the UHU, gecko etc via a USB to serial or parallel converter ?

any potential problems/incompatabilities ?

cheers as always,
nick

[abasir]

The general concensus is that it will not work. It doesn't even work in standard intel-windows setup (via USB-Parallel converter).

The reason is that standard USB to parallel port converter are meant for printers and windows have special codes to make that work for printers. For CNC, software are accessing the printer port directly (bypassing windows built-in codes)... not possible with USB-parallel converter.

[abasir]

On second thought...

If you intend to write your own software, why not get a USB-Parallel port chip/module such as (http://www.dontronics-shop.com/produ...cat=322&page=1). This way you could write your own protocol to talk to the gecko, etc. It is doable...

[unterhaus]

I'd get a pc. EMC will run over telnet, so it could be used on a Mac with a pc as the realtime controller. There are other options out there, they would require a significant amount of development.

[nick mulder]

Originally Posted by unterhaus I'd get a pc. EMC will run over telnet, so it could be used on a Mac with a pc as the realtime controller. There are other options out there, they would require a significant amount of development.

The new macs are for all intensive purposes are PC's - there is no emulation, its running natively on the apple hardware using intel duocore chips..

its just a PC without a parallel or serial port

[nick mulder]

Originally Posted by abasir On second thought... If you intend to write your own software, why not get a USB-Parallel port chip/module such as (http://www.dontronics-shop.com/produ...cat=322&page=1). This way you could write your own protocol to talk to the gecko, etc. It is doable...

thats a great link there, thanks!

my end goal is to use a 3D animation program like Maya to program motion paths in 3D space in which virtual cameras will travel, the positional information (xyz) and pointing info (pan,tilt,roll) with respect to time of these cameras will be outputted to another prog which i will make that will convert this info into the required step/dir info for the 6 or more axes of a real physical motion control system that has a real camera appended ... (a very simplified explanation)

In the meantime I plan to CNC a mill with some servos and UHU boards with which it will help me make the motion control system above - the UHU needs step/dir signals which would come from mach3 or similar ...

>> can mach3 output its signals to this module you have linked or do I have to code my own controller software ? :yikes: ?

I'm reasonably at home with basic kinematics, dynamics, calculus & coordinate math and a little bit of coding (enough to know what i dont know yet) so the Maya3D position to discrete velocity conversion is ok in my head at least, but I know nought to do with G-code and was hoping to simply use something like mach3 or similar


the UHU also use RS232 protocol to set up its PID parameters and wotnot ... I think it uses AVR's - also a lot of PIC programmers use RS232... is it as simple as getting a $20 converter for this ?

[unterhaus]

I know a mac is just a pc nowadays, but the software and the hardware available make all the difference. If you can run Windows XP, then there is a good chance that Mach 4 and a GRex will work for you when they become available, but I doubt this is what you want. If you can install an actual hardware parallel port (they have pci express or anything like that?) you could run Mach 3. There is the CNCDudez (sp?) usb device, which probably will work. And a GRex might work natively with a mac eventually. You probably could put something together out of EMC, it's open source and it's been done before. You could probably run Linux and EMC natively, don't know what hardware you would use, again, you need a real parallel port or other supported hardware interface.

[nick mulder]

EMC - very interesting...

I will attempt to get linux going on the mac and then a conversion of EMC to output to the microUSB I/O device abasir linked to -

:uphill_struggle: !

but I'm in for learning (;

[abasir]

Mach 3, as far as I know, will not work with the module I linked. The module will appear as serial port rather than parallel port.

Also take note that USB communication do not necessarily happens realtime as opposed to talking to the parallel port directly.

[nick mulder]

Originally Posted by abasir Also take note that USB communication do not necessarily happens realtime as opposed to talking to the parallel port directly.

I'm no expert but I would have thought that if there are for example USB sound cards that are used in audio recording that latency would be small or at the very least constant ?

As my application is time dependant what sort of error/delay could i be looking at with parallel type output via USB ? does it accumulate per axis ?

[fkaCarel]

This link will give you an introduction in the world of the other side of the cable:
http://www.cypress.com/portal/server...&showall=false

USB is also called a conspiracy between Intel and Microsoft to maintain the need for ever increasing processing power. It's at least complicated.

Carel

[imserv]

DeskCNC should work fine on the XP booted mac computer. A USB to serial adaptor is all you will need.

http://www.imsrv.com/deskcnc


Fred Smith - IMService
http://www.cadcamcadcam.com/hobby