To rrc1962:

You mention that your controller is only 4 axis; is there something else in your system that makes it able to handle 6 axes?

Richard B

No.  I didn't realize you needed 6 axes.  

Thanks BR449,

Do you have any recommendations for hardware for this?

RB

You would, I imagine, already have the drives and likely a breakout board as you have been using the ncpod so you dont really need any further hardware other than a computer with a parallel port and a PCI parallel port if you require a second port.

What kind of motors do you have? If just steppers then you will almost certainly be able to get their max speed from the parallel port.

Hood

I have motors (steppers, nema 23) and drivers, but no breakout board. Can't remember why I didn't need one, but I remember being told either the drivers or the pod do this instead. How much are parallel port controllers/ breakout boards, in general?

You dont actually need a breakout board but I prefer to use on mainly for the ease of connecting but they also usually afford a little protection if they are isolated and a further benefit when using the parallel port is that most can accept the 3.3v signals some modern ports put out and will boost it to 5v for your drives.

Cost wise they go from cheap to expensive, my personal preference is the PMDX122 which will be around $80 but there are cheaper ones from other makesrs and also dearer ones, for six axis and the I/O you would need 2, if wanting breakouts for each port. There are also dual breakouts, I think PMDX do some and as said there are others that make boards.

PCI parallel port I am not sure, in the UK you would be talking £10 to £20 so it would probably be the same in $ for you.
Hood

Okay, so if I have a smoothstepper I have to have breakout boards, but if I use the parallel ort I could theoretically just wire my drivers directly to the port on the pc? Is that correct?

From reading on the site, I'm not clear how many axes the PMDX122 supports...

I'm in UK, too! Do you know what the shipping charge is likely to be for the smooth stepper? They're all on holiday at the moment, apparently.

Rich B

You could wire directly to the PP, but if the drives create any spikes it will fry your PP.  Breakout boards are opto-isolated to prevent that.  They also provide opto-isolated inputs.  They are well worth the little bit of money they cost.  You should have a BOB with both SS and PP.

So I ought to use breakout boards if I have SS or PP.

On running Mach's driver test, my PC was rated good to excellent for pulse, so does this mean I don't really need an off-board controller/pulse generator?

My (motion control products msd415) drives have , and I quote: "
TTL compatible and optically isolated input signals". I will mail them to ask, but does that mean I don't need a breakout board? It's starting to sound like all I need to do is tear up an old PP cable and wire my drivers to it. For 6 axes, I'll need another parallel port though, right? Would a PCI parallel port work identically to my on board one? No issues to look out for?

I ought to check that my PC is producing 5V not 3.3V to the parallel port. No idea how to do this, can I do this in xp sp3? A link to a walkthrough would be a help.

I think that's all!

Thanks for advice so far, I really appreciate this,

RB

I'm pretty sure that the opto-isolation in the drives is there to protect the drives, not the PP.  I tried going direct to the PP with Gecko drives a few years back and popped the PP within about 5 minutes.  Since then, I've always used BOB's.  All it takes is a little stray voltage to a PP pin to blow the port.  These are low voltage signals, so it's not hard to get that, especially when working with plasma.

You would need an extra PP and BOB.  A PCI card will work the same as your on-board PP.

Then that's what I'll do! Thanks, I think I've got a shopping list to write.

RB