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Author Topic: Ports and Pins and Homing - G540  (Read 1383 times)

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Ports and Pins and Homing - G540
« on: February 04, 2017, 10:24:38 AM »
So I have a question that I'm looking to understand how this is currently working with my setup...

I have my limit switches wired in series for X/Y/Z and a I have a slaved motor on the X Axis (A) which is wired independently, they are using 2 inputs on my G540.

On the Configuration/Ports and pins page I have X,Y and Z on Pin 1 on my G540 (Input) and the A Axis on Pin 2 (Input). see attached

This is working perfectly but I'm trying to understand just exactly how the machine knows how to home itself?

I realize that my X Axis is squaring itself based on the X/A Axis and that is the need for having them on separate input pins. Since X,Y and Z are wired in series, tripping any of the Axis opens the circuit so how does it know when the other Axis are homed since the circuit is now open?

Re: Ports and Pins and Homing - G540
« Reply #1 on: February 04, 2017, 04:26:34 PM »

It's quite simple really. Mach3 homes one axis at a time. So as it homes an axis, and the input with the X/Y/Z in series switches is activated, it can only be the switch for that axis that caused the activation.

If the machine was homing the Y axis for instance, and you manually pressed the Z home switch with your finger, Mach3 would incorrectly assume that it has hit the Y home switch.

If the same switches are used as limit switches, Mach3 doesn't know which axis tripped the limit switch input as multiple axes are in motion. It doesn't care as it just EStops the machine.


Homann Designs
email: peter at homanndesigns.com
Re: Ports and Pins and Homing - G540
« Reply #2 on: February 04, 2017, 08:26:01 PM »
Ok great!

Thanks for the insight, I assumed that was the idea but hoped to verify my suspicions.