[EZMEF]

I have gecko g540 and Mach4.

I have a home/limit switch at the top of my Z. When I ref all, the axis goes up to switch, then backs off, works correctly.
I just bought a Z probe off of Amazon

Here is my question, can I connect the wires from the probe to the wires on my Z limit switch? Then can I activate the same pin in Mach4 for the probe function? It’s no different than having 2 limit switches on the same axis.

The reason I need to do this is because I have a burned out input on my g540. The other 3 inputs in use are limit/home for X,Y,Z. I do not have a BoB( don’t want to get one unless I absolutely have to.)

Hope that makes sense
EZ

[awerby]

If the limit switch and probe are both normally open, I would think that connecting the leads in a "Y" configuration would allow the current to flow when either were triggered.

[EZMEF]

Here is where I’m at.

I installed a cnc4pc C25S Break out Board, BoB.

I was going to put the wires from my limit/home switches and put them on the BoB, but I just left them on my g540.

I pulled the ribbon cable from port 1 of my ESS and put it on port 3 of the ESS, then connected the jumper for port 1 to get 5v to BoB. Then piggybacked C25S to my ESS.
I configured all my inputs and outputs to port 3. Everything works as it should, limit/home, homing, and motor motion.

On the BoB I Tested voltage across pins 5v and GND and got + 5v reading. (Power to BoB)

I installed a simple probe, a plate and alligators clip.
As per instructions, connected one wire to a 5v pin on the BoB and the other wire to input pin 15 on the BoB.

I configured everything in mach4 and ESS.
With the plate sitting there, clip not connected. I start the probe function on mach4, my z axis starts going down, if I touch and hold the alligator clip to the plate, z stops, then backs off. Looks like it works how it should.

BUT, If I have the alligator clip on the bit. The z probe function stops and doesn’t work. If I have the alligator clip off the bit and start the function ( z will move) then touch the bit with the clip OR the plate separately, it stops.
Like I said, with the clip not connected to the bit, then I touch and hold the clip to the plate. I t looks like it works how it should.

I tried changing the high low state, didn’t help.

Any ideas on what to do. I’m stumped.
EZ

[HighSideNZ]

Sounds like the frame of your machine is ground (0v) so as soon as you connect the clip the the cutter the circuit is complete and so it stops the probing process.

[arturod]

It is not a good practice to activate the signal with the ground of the machine's frame. Try getting one of those probes that isolate the ground of the machine.

Arturo Duncan
https://cnc4pc.com

[phomann]

I have gecko g540 and Mach4.

I have a home/limit switch at the top of my Z. When I ref all, the axis goes up to switch, then backs off, works correctly.
I just bought a Z probe off of Amazon

Here is my question, can I connect the wires from the probe to the wires on my Z limit switch? Then can I activate the same pin in Mach4 for the probe function? It’s no different than having 2 limit switches on the same axis.

The reason I need to do this is because I have a burned out input on my g540. The other 3 inputs in use are limit/home for X,Y,Z. I do not have a BoB( don’t want to get one unless I absolutely have to.)

Hope that makes sense
EZ

No this won't work as the probing functionality is separate from the limit switch input.
As far as I understand, the limit switches are continuously monitored. If you activate the z-limit during probing, Mach4 will think that the z-limit has been hit and estop the system.

You would be better to wire the X,Y,Z limits in series in a normally closed configuration. That way you will free up 2 of the G540 inputs. Then use one of them for the Z-Probe.

Cheers,

Peter