Essentially it looks like you have it correct.
The 5v supply commons of each will have to be connected together.
The DRO supply common may be at Earth Ground potential, this may or may not be a problem, depending on what method of grounding or isolation you are seeking.
The +5v should not be connected together.
Depending on the internal condition of the drive input, you may not need a pull up with the 75176?
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.