Which Mesa board?

Clive, very good! The set up I have only uses step and direction DC servo drives on XYZ and a hybrid stepper motor on the 4th axis. Everything is still step and direction. The spindle is just on / off relay.
So I think the 7i76e will be perfect. Just need to check on pull up or down version. I think all my limit and homing proximity switches are NPN. That fact will determine my sinking our sourcing option.

Just clarifying that the 7i76e has its own opto couplers that if are enough to cover my 1/O requirements wont require an additional BOB?

palmac wrote: Clive, very good! The set up I have only uses step and direction DC servo drives on XYZ and a hybrid stepper motor on the 4th axis. Everything is still step and direction. The spindle is just on / off relay.
So I think the 7i76e will be perfect. Just need to check on pull up or down version. I think all my limit and homing proximity switches are NPN. That fact will determine my sinking our sourcing option.

Just clarifying that the 7i76e has its own opto couplers that if are enough to cover my 1/O requirements wont require an additional BOB?

PNP switches connect directly. NPN's need a pullup resistor, or use a D board

7i76 has 32 ins and 16 outs. need more? use a 7i84 which can connect directly to the 7i76. That gives you 32 more inputs and 16 more outputs.

Ah, Bevins beat me to it.

And yes no other optos required. Just the flyback diode if switching higher loads.

Use 2.2k Ohm 1 W pullups on Non D version.

And there is not really any excuse not to run seperate min and max limits and homing switches with the number of inputs available

bevins wrote: PNP switches connect directly. PNP's need a pullup resistor, or use a D board

Bevans, I think you mean NPN's need a D board don't you?

rodw wrote:

bevins wrote: PNP switches connect directly. PNP's need a pullup resistor, or use a D board

Bevans, I think you mean NPN's need a D board don't you?

yeah, thanks for catching that.

These are what I use for the limits and homing an all axis, NPN.nc.
So I need the 7I76ED ?

Thanks.