Need some wiring help with board...

Yossarian,

Yes, you are correct. The enables and fault output are all 5v. You don't need a 24V supply in there. I gather that's probably what John was telling you in the other thread.

Len

If 5V, you can still wire them directly to the first 4 inputs on the 7i77, set the board to mode 2 and add some hal logic to trigger when that input reaches 5V.
This sounds way over my head.
Where would I start looking to find out how to do this?

Those drives have one major issue that needs to be fixed before proceeding any further, namely the inhibit input is reversed, meaning if left unconnected the drives will be enabled, and that is a big NO for servo drives.
That can be foxed by adding a resistor to pull that input low always until Linuxcnc takes control and sends the required 5V for enabling the drives. A 1KOhm resistor should do the trick, but you will have to test that and be sure that the drives remain disabled until the enable on Linuxcnc is turned on. That input then must be connected to enable on the 7i77 for all drives separately, and the other side of the 7i77 enable connected to 5V.
The fault can be connected directly to one of the first 4 inputs on the 7i77, namely the input 0, 1, 2, 3, and those inputs should go through a comp as to trigger the fault for each axis when the input value reaches 5V, not hard to do in hal once you get the hang of it.
Do not proceed without testing the resistor part, having enable working correctly on servo driven machines is a must, there is no way around it.

Ok great, so do I connect the resistor to the inhibit in to the signal ground on the drive?

Catch22 wrote: Ok great, so do I connect the resistor to the inhibit in to the signal ground on the drive?

Yes, inhibit it and the other side of the resistor to signal GND.

Your understanding of signals and grounds seems to be a but confused as you appear to be asking where to connect grounds to.

Say I two device X & Y
Each Device is Powered by a separate power supply, say X is powered by switch mode powersupply and Y is powered by a battery.
Device X has 2 terminals X_Out and X_Gnd.
Device Y has 2 terminals Y_In and Y_Gnd.

To connect Device X to Device Y:
Term X_Out ===> Y_In
Term X_Gnd ===> Y_Gnd

Without Y_Gnd & X_Gnd being connected no signal will be seen.

Now X_Gnd & Y_Gnd are common. Theoretically if Y_In needed a pull down resistor it doesn't matter if the resistor connects to X_In & X_Gnd or Y_In or Y_Gnd. Even X_in & Y_Gnd are valid. As X_In & Y_In are connected electrically and X_Gnd & Y_Gnd are also connected electrically.