[rezcar]

Hey guys I have an X3, CNC Fusion, G540, Mach 3 setup. Homing and limits were working perfectly for the past couple of months, then all of a sudden, the switches aren't stopping the machine.

They are, NC, in series, and not showing any yellow trip lites in the Mach diagnostics screen. I tested them with my DMM and all are working fine, I also checked the wires and there is continuity all the way around, I manually actuated the switches and checked that the loop opened.

Is it the G540? I tried another input terminal and still no good. My probe setup using Hoss' screen also stopped working at the same time. Or is it something in Mach 3?

Help!

[Fastest1]

I would be suspicious of the Mach since Hoss' screen died at the same time. You did try just rebooting didnt you? You didnt mention it.

[knudsen]

They are, NC, in series, and not showing any yellow trip lites in the Mach diagnostics screen. I tested them with my DMM and all are working fine, I also checked the wires and there is continuity all the way around, I manually actuated the switches and checked that the loop opened.

I don't do cnc yet, so take this with a grain of salt, or dump it if someone else chimes in.

So, you have a loop of continuous wire that runs through the switches, unless one is open. If you open that up, it should think you hit a limit and stop the mill, presumably with an error. I would run it and open that loop and see if it stops and gives an error. If you can unplug something to accomplish this, that would be the easy/non-destructive way. If you can (safely) reach a switch with it running and open the switch, that would be a good test. Maybe use a pencil to activate one? Safe and the pencil won't likely damage the works. If you are fed up and want to get rough with it, snip a wire, opening the circuit. If you cut the wire with it running, it should think you hit an end limit, as well as burn off some aggravation (nuts) Might be not a good idea. Maybe you can just unplug it from a connector?

If you can find a way to open the circuit, it should think you hit a end limit and (presumably) stop the mill and give error. Maybe you can wiggle the micro-switches with a pencil while it runs? It should error out and stop if a switch opens. I hope someone offers better advice, but that's what I would try. If the circuit is opened, it should stop the mill. Please keep in mind, I've never seen one of these in person, and this is just what I would try. If any one offers advice, it's likely better than my blind shot at what to try.

Good luck!:rainfro:

[rezcar]

Thanks guys,
Fastest1, I don't really know if Hoss' screen died. I changed the input terminals and no dice so it may be the G540. I called Gecko and the guy thought the same thing. I'll try the stock screen set and see if that works.

knudsen,
That's pretty much what I did with my DMM. First I tested each switch and they were fine. Then with the mill in motion, tried hitting the switches and it still wouldn't stop, nor flash the diagnostic LED. I'll try a direct wire from the G540 to a ground, bypassing the entire home/limit circuit to see if that identifies anything.

I can't take the G540 til next week so I'll keep trying to troubleshoot in the meantime.

[knudsen]

Be careful what you shunt to ground. Just guessing, the switches go to ground at one end of the circuit, and to the input of a chip at the other. I'm guessing the ground through the switches acts like the input to a logic chip, and when it's gone (i.e. a switch opens) the software "sees" that as a limit switch tripped, shutting it down and giving an error. If that is true, shorting that input to ground will bypass the limit switches and just make it run all the time. Removing the jumper should make it stop with a limit error. But if we are wrong about how it is supposed to work, it could damage the board. Hopefully we don't fry a good board.(nuts)

[knudsen]

Also, please keep in mind, I have a very limited knowledge of these systems. I have some electronics experience from eons ago, and that's what I'm drawing on. I'm not "up" on these systems, and would hate to see you let the magic smoke out of the board. Once the smoke gets out, it's probably dead.

[Fastest1]

As a test I would run a wire in place of the limit switches and disconnect it once the reset had had been done and see if it trips. Are your settings correct in Mach? Go in and change it from active low to active high and see if the diagnostics light changes. Also make sure it is enabled in ports and pins.

[rezcar]

It's alive again!
Knudsen, the input circuit for my setup is supposed to go to ground, or -VDC common actually.

I wired directly from the G540 to -VDC and still no dice so removed the lead and found that the shielding from my wire worked its way out and was making contact with something. Replaced the wire and went back to the Hoss screen and all is good :-)

Fastest1, I did have to change my settings to active high. Maybe they were that way before, I vaguely remember forgetting to turn on the control box before starting Mach 3 and got the "do you want to have Mach 3 change the settings for you?" error screen. I probably hit ok, not knowing my wire was rubbing on something.

Thanks guys for your help!

[Fastest1]

Fantastic! I cant tell you how many times errant grounds have caused faults in my case. Almost every time (read every time) I bring or build a new toy home to connect to my controller it stops working. It has happened with my probe, my touchplate, speed controller and tachometer. All separately created problems.