Mach 4 not "seeing" limit sensors/ crashing

I’ve had this happen before but restoring from backups fixed it. This time I went as far as to uninstall/reinstall of Mach 4 but the problem persists. On startup, when I home the machine, it crashes every direction (although it does Z first and I can’t really get beyond that).

It does not stop from the proximity sensors even though they appear to be working and light up. I can test the X and Y with a piece of metal and see them light up, but not stop moving, (that’s how I know it’s not just the Z.)

So while the sensors are working, the machine is not getting the message. Any ideas what to check or how to fix this? I see this came up before in the forum but I have not seen any solutions. thanks.

Is it possible you have the sensors plugged into the wrong ports? Y in the Z port for example? When you say the sensors light up when triggered, are you referring to the sensors themselves, or on the software interface. When you trip a sensor, the software interface should light up showing which axis the sensor is wired/napped to.

If you Z axis sensor is plugged into X or Y, I believe that would cause the issue you are referring to. So when you home, and Z axis motor moves by itself first, it runs into a sensor but the motor is not told to stop because the actual Z sensor hasn’t tripped (X or Y has), thereby causing Z axis’s to crash into the bumper.

Just a thought.

I wish it were that simple. I’ve been using the machine for years and nothing physical has changed. I checked all the plugs to see if they were loose or anything. At 9 am I homed it without a problem, ran two files, then at 2 p.m. I rehomed and it wouldn’t stop and keeps crashing, even after reinstalling software and many reboots.

It’s hard to believe all your sensors would have the same failure mode at the so intermittently at the same time. I will be curious to watch and see what the final solution turns out to be! Could it be an intermittent machine ground problem effecting the AC>DC power supply to the sensors?

I know! Which is what leads me to believe it’s software, but striking out on all attempts there. But you may be on to something. Maybe some sawdust or whatever is in the control box, tripping something up? I’ll try blowing that out…

Technically the DC step converter does NEED to be tied into ground, but should be. If it isn’t is could be creating gremlins due to EMI. Also, you might check the DC voltage the step converter is putting out. Maybe it’s failing or voltage has dropped off below the minimum required by the sensors?

Man, I’ll need to figure out how to test all that and what the currect numbers should be. Adding to the mystery, If I turn soft limits on in mach 4, it establishes seemingly random points to stop, several inches from the actual edges of the work area. Like it just made up these locations? So weird.

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I’m on it with someone there and we THINK it’s the board for all the sensors as the problem is across all of them. It’s getting mailed out and I will keep the forum updated.

Solved: The “CRP860-00E Break-Out Board” went bad. This is the board that all the sensors are plugged in to at the bottomof the controller box. real easy to swap out. Hurray!