Left...
On your R90H drives (3) you have a DB9 connection. This is your encoder connection. Depending on your encoders you most probably only need 7 pins.. 2 for + & -, 2 for each channel(a & b) and one for the shield. Have you downloaded the PDF for the drive from
www.Rutex.com . The PDF explains if fairly well... I am just hooking up my encoders today.
It may be wise to run seperate wires for the power (+ & -) and the channels to minimise any electricial interference.
cheers
Frans