Mesa 7i76e – putting the GND signals together?

Hello,

I think I worded the title poorly, but I'm not sure how else to put this into few words.

Hardware-wise, it's about connecting the Mesa 7i76e and JMC closed loop steppers.

The Mesa 7i76e has differential outputs, so instead of the GND going into the same spot, there's one for each output (Dir+ and Dir-, Step+ and Step- and so on). But it also has a GND pin per axis.

Now, I understand the advantage of differential signals in theory, but I'm not sure it's worth the effort here. Like, putting all GND together on the driver side (a JMC stepper in my case) saves at least two wires (I played around with the motor and another board and the Enable input was not needed, so I guess I won't connect it.). That means it's considerably cheaper and it reduces things that might break.

Anyone got any thoughts on this?

If you want to use single ended connections. I would at least use one ground per driver
so 3 wires per driver (Ground, STEP+ and DIR+) with STEP- and DIR- left unconnected
at the 7I76E.

PCW wrote:

If you want to use single ended connections. I would at least use one ground per driver
so 3 wires per driver (Ground, STEP+ and DIR+) with STEP- and DIR- left unconnected
at the 7I76E.
 

Yes, that was pretty much my plan.

I'm still unsure whether it's a good idea in the first place, though. I do have differential in- and outputs, after all. Maybe not using them is kind of a waste.

I doubt I'll use the Enable Signal, I know the motors work fine without it and honestly, I don't understand what it's for in the first place.

Alarm and Position Signals are nice to have and I think I'll at least wire them up, even if I might not use them right away (one step at a time).