I am happily driving 2 x axis motors off a "shared" dir/step channel so the 4th axis on the PMDX can be used to drive the 4th axis. ALL works very well and no issues to date. Almost 10 months of hard work out of my machine thus far - perfect.

Sean

For those wanting 5 independent drives from the PMDX-122, I believe a 5th drive could be configured for step and direction off connector J8 at the top right:
http://www.mechmate.com/Forum/messages/832/1904.gif

There you have a GND and +5V, which could be the COM for G203 (GND) or G201/2 (+5V) drives. Mach3 can be configured to give the Step/Dir pulses on either pins 14 & 16 of that connector J8. Havn't tested it myself, but it seems feasible?

But then G' we need more outputs for the Spindle control

Me and Vishnu have opted for a serial interface based board for spindle control
http://www.soundlogicus.com/SPINDLEC...6/Default.aspx

RGDS
Irfan.

We use the J7 connector (bottom right of the PMDX) for spindle on/off and a simple potentiometer and knob for spindle speed (like a volume control). Mach3 turns the spindle on and off, while the operator picks the speed manually to suit the material hardness and the cutter bluntness. No extra board required.

hmmm G' you were too late to mention this - I already ordered two of those spindle control boards :(

RGDS
Irfan

How did you think we controlled the spindle? By the way, the digital readout of the VFD shows the speed dialed by the potentiometer knob. It is a very simple setup.

I thought u had a manual on off - and yes I look at it now - my mistake completely - but anyways it might be good to have a automated control over speed, another parameter less to be concerned of. :)

. . . . . . . more likely another parameter more to be concerned about during programming.

When you cut a test pattern first in MDF and then in oak, do you really want to have to change the program?

hmmm.......

don't worry then I will use the pot then :) - G' let me self justify the purchase of the spindle control board :)

but you are tight too - a fact is a fact :)

I can see where programming the speed can be useful, such as when cutting across the grain versus with the grain, or a V-cutter going fast on a shallow cut and slower on a deep cut. But everybody seems to program one speed at the beginning of their cut file and don't change it again.

And almost 10 years later, it still holds true.