Mesa 7i76E and JMC Steppers – Edge up or down?

Hello,

I expect this to be a super niche problem, but maybe someone dealt with it already or has a hint for me, how I could figure this out.

On the JMC Stepper Driver, there's DIP switches and one of them allows me to choose between rising and falling edge. What I determined by now is that this refers to the way signals are interpreted, namely whether an electric signal is interpreted as a "1" or or a "0". Thing is, I don't know which is the right choice and how to even determine that. Apparently, the wrong choice may lead to lost steps, but frankly, my machine is likely to be so imprecise that I'm not sure how to notice it until I meet a situation in which it might've mattered.

So, any ideas?

TIA

Assuming that "rising-edge: means opto-coupler LED illuminated
I would use rising edge and standard single ended connections:

Drive Step+/Dir+ to +5V
7I76E Step-/Dir- to drive Step-/Dir-

Are you sure? According to me "rising edge" means, that puls is active in log. H.
So when set to "rising edge", connect 7i76e Step+ to Step+ on driver, Step- on driver to GND.
When "falling edge", connect 7i76e Step- to Step- on driver, Step+ on driver to +5V.
Signal Dir the same way.

Yes, I'm pretty sure.
"rising edge" is not as simple when dealing with differential inputs.
For example if I have a standard step drive and I connect STEP+ to +5V
and STEP- to the controller. the controller must output active low step pulses,
even though the drive is set for rising edge. In my experience the active
edge is almost always the one that illuminates the optocoupler LED
If a drive with optocouler inputs is set for falling edge, I would expect it to
step when the optocoupler loses drive.

Yes, you are right. Both variants are possible. My mistake.

For "rising edge":
7i76e Step+ to Step+ on driver, Step- on driver to GND
or
7i76e Step- to Step- on driver, Step+ on driver to +5V.