breakout board usb or parallel

[crossleymarko]

really just want to know the difference, other than price between the 2. i know the usb ones are expensive. but ive also read no need fo mach3 , how does this work. also is the parallel board a pain to set up..

thanks

[Robin Hewitt]

Mach 3 has a clever trick, they hack deep in to Windows and take over a hardware timer so they can step in real time. Windows hates this and got better at protecting itself with each new revision which is why MACH doesn't work passed XP.

If you go USB then you lose all the critical timing and you have to send a pre-digested sludge down to the machine which includes the step rates and makes MACH somewhat reduntant.

Hassle is, MACH is the hobby industry standard and as soon as you start pre-digesting you step out of the comfort zone and chain yourself to a single supplier who may go down the tubes leaving you high and dry. MACH is unlikely to demise until a new standard is accepted. It's catch 22.

Having said that, I drive my mills via USB on Win7 without any restriction on running other programs at the same time. Do you have the pioneering spirit? You may end up with arrows in your back :whistle:

[crossleymarko]

So a machine running XP and a parallel board is the way to go. I didn't know Mach didn't work passed XP.

Sent from my HTC Desire HD using Tapatalk

[m_c]

Mach itself does work past XP, however it's the parallel port driver that suffers under later versions of windows. The driver can be made to run under Vista, but can be a bit hit or miss.

As Robin has said, if you go USB, you are at the mercy of that vendor, however go for something proven and popular, then you shouldn't have any issues. KMotion and SmoothStepper are the common options that can still utilise Mach3 (KMotion can work standalone), but there are a couple others that don't rely on Mach.


I've been following Art's and Brian's posts on the Mach Yahoo group over the past month, about the development of Mach 4 and a new Parallel Driver, along with the issues they're facing, and basically short of some major coding, the parallel port driver isn't going to work with any new versions of windows.
On the plus side, Mach4 is basically going to be a quite minimalist core, with planning, motion and interfacing all dealt with by plug-ins, so is going to open alot of new possibilities.

[John S]

The parallel port driver inside Mach3 works and works well for all general work.
Where it falls over is in threading on lathes, it works for some but not others.
The new drive for Mach 4 called Darwin has just been started by Art who still owns the rights to the driver, not Brian.

I'm working with Art on a test version just for threading. Decisions will be made about backwards comparability later, by whom I don't know, presumably Brian.

The problem with the add ons like K Flop and Smooth Stepper is increased cost and complexity.
I have looked at USB devices and do not like them as you are tied to the one developer who has written in stone how it works and looks, at least with Mach you can customise to your requirements.

[Robin Hewitt]

I have looked at USB devices and do not like them as you are tied to the one developer who has written in stone how it works and looks

That's why I write my own. Nothing quite like having well commented source code when things go wrong :whistle:

This is fresh in my mind because my current system is limiting me and about to get rewritten. I want the industry standard, up to date processor. Has to be ARM 32 which is cheap as chips, goes just as fast as you like, loads of goodies and oodles of I/O pins. Also tempted to go Ethernet like the big boys.

These new smilies are crap :frown-new:

[John S]

That's why I write my own. Nothing quite like having well commented source code when things go wrong :whistle:



So again you are tied to the one developer ? :stung:

[Lee Roberts]

Dont forget to click the "more" link under the smilies on the right, they are part of vB not my choice. :tranquillity:

[z3t4]

The parallel port driver inside Mach3 works and works well for all general work.
Any suggestions about which parallel cards work well (eg an ebay linky)? Tomorrow a KX3 is going to follow me home and I want to make it feel welcome :smile:.

[Robin Hewitt]

So again you are tied to the one developer ? :stung:

Absolutely, but when things go wrong I don't just send a hopeful email and join the queue :sleeping:

[John S]

Just get an older computer with built in Parallel port, The Dell Optiflex works out fine.
If you are collecting it from ARC you are free to call into here, M1 J24, and pick a computer up if you want I normally keep a few in stock

[z3t4]

Thanks, John.

[crossleymarko]

i dont know what breakout board i have. got it with 3 m542's as a kit.. not tested yet. so how do i tell what board i have... is there an ic on board...


thanks

[Nugget]

bit late to the thread. interesting about mach3 and the system timer enabling real time control. I wondered how that worked since desktop OS'es are not supposed to be real time. is this an issue with Linux CNC (emc2)? in fact I thought it made sense that an external controller did the well controlling since that was the only thing it had to do. I was wondering if you had any experience with the Smoothie project. it runs on a low cost ARM board and contains its own g-code interpreter.