this is somthing that is needed.
I was looking for a wile recently
on mine so far I just have the encoders connected to the drives and all that is connected to the grex from the drives is
the step and direction wires from each drive to the step and direction axis connections on the G-Rex
I amjust ready to start motor tuning so
I cant say that I have a running setup yet
but I called them and they told me that was all I needed to connect
that and the 5 volt from the grex to the common
on the drives to supply the power
I tried to take a picture of what i have so far but my camera decided to die tonight.
also they recommended a capacitor digi-key part number P10874-nd connected to the connection 1 and 2 on the drives the (power ground) and the (+ 18 to 80)
if the wires are over 18 inches long from the power supply
mine is about 24
I hope this was some help