I don't want to upset you but you may be looking at either buying a servo and swapping it in with a DC1 or just selling off the 4th axis and finding a DC servo version and buying a DC1.
(below is a bunch of techno BS, but from what I have read this has some merit, all options are outside of my abilities, if other members see issue please feel free to jump in and comment if I am incorrect)
At some point the Ajax Mach driver captures the trajectories and commands the motion control board (MPU11) via either net.
If the driver were done in such a way where the pulse train could still be sent out of the parallel port you might have a chance but the stepper would not be synchronized with the output from the motion control board in all likelihood.
You could try and index but would never be able to use as a true 4th.
If you were a die hard micro programer you could buy an Arduino board for cheap and write some code to try and drive the 4th off the velocity commands. (for the MIT graduate, 50/50 chance of usable results for mere mortals) At best you could use the PLC to shoot index commands to the a home grown micro Arduino based indexer control for the stepper. (good chance you can do this with sweat equity) This would be the cheapest option to try and use your setup. Get ready for 200-400 hrs of hard work to figure it out before even cutting your fist chip. Here is what I believe: "No problem can withstand the attack of sustained thought"! I also do not think this is worth the effort if this is to make money, but it would be a challenge you could learn from. When we got to the moon there was great fan fair, the true triumph was what we learned in trying to get there.
Why the US has turned it's back on NASA is a real F-ing shame.
http://www.ebay.com/itm/Crazy-kit-for-A ... 19cf6cb7ea
I am going to buy the CNC11 software once I can scrape up the cash, I bought a used Haas 5c indexer with a dead control for 200.00, I will eventually buy a DC1 and an encoder to run it. I am making money with a lathe I bought and will take on milling jobs once my mill comes to life. My strategy is least effort maximum return.
Thanks AJAX for the affordable kit.
Best of luck,
Chris
