3-axis Machine - Electronics Diagram

[Manuks]

I want to build a 3-axis cnc machine. The thing is I have no background in electronics or mechanics whatsoever. But at this point and after reading a lot of threads and related sites I can say I now know a little bit of everything.

Now I´m trying to figure out how to assemble all the electronics together. I have some NMB PM55L-048 steppers (24v, 800mA). I know this is not the best choice but for now it´s the only one.
For the driver I choose the L297 Unipolar design from PMinMO (Thanks to Phil) and for the interface, aslo from Phil a 4-axis BOB.

Links to both boards:
*Interface: http://pminmo.com/4axis/4axisBOBdata.pdf
*Driver: http://pminmo.com/l297unipolar/l297unipolar.htm

Few questions:
* the logics of the driver board feeds from the 5v through the IDC (from the interface) or directly from the PSU through X4 wago terminals?
* Is the motor connection (5 wires) ok?

Diagram:


Is that correct?! I something missing?
Thoughts and comments are very welcome!

[Manuks]

I´m having trouble understanding the current limiting system. In this case, L297 Unipolar board is equipped with chopper current limiting. I think because of the voltage of this motor (24v), no current limiting is required.
But, lets say I have a 5v motor. Should I use a resistor between the PSU and the motor besides the current limiting circuit? I thought it was one or the other but not both at the same time.

[Manuks]

I´ve been studying motor internals and now I wonder why does the driver needs to be fed by the PSU. I understand now that bipolar driver do need to manage the flow of electricity through the H bridge. But unipolar drivers just directs the flow coming from the center tap of the coils (from + of PSU) to the negative (-) of the PSU either from one terminal or the other of the coil. Is that right?? or am I even more confused than yesterday?