Homing is triggering limit

[mattsshop]

Hello,

I have had my UC300-ETH up and running for a few months doing production work. I came in the other day and went to home the machine and it limited out on the x axis while homing, I baked off the axis and homed again and it limited out on the Z axis (it would do it on X,Y or Z randomly). After several attempts and restarts it finally homed out and I ran the machine for the day. Today after the weekend I come in and it did it again, with no end in site I went to the axes setup and disabled limit pins on all axes and it homed with no issue but now I have no limit protection on the any axes(which may not be an issue). Would anyone have a suggestion of where to look for a solution, Any suggestion would be great.

Thank you,
Matt

[fsli]

I came in the other day and went to home the machine and it limited out on the x axis while homing, I baked off the axis and homed again and it limited out on the Z axis

I'm trying to understand this a bit better. Are you saying that the gantry was moving towards the X home position when the X limit was triggered? Or the gantry was moving in some way, and some other limit got triggered? Was the machine anywhere near the limit switches when they triggered?

If you're using mechanical switches for the limits, I'd want to start looking at whether they are broken, clogged, or shorting somewhere between the switch and the UC300.

[mattsshop]

Hi Fsil, when I home the machine and the axis reaches the home switch which is also the -limit switch the machine sometimes "limits out" and triggers an estop instead of homing the axis out which causes me to do a reset and start homing again. sometime Z would home then X would limit or Z and X would home and Y would limit.

The limit/home switches are proximity switches and I have tested them in several ways and they have no issue. As I said when I 0 out the pin and port for the -limit in the axis setup for X, Y and Z the issue goes away, so that tells me the switches are ok.


Thank you,
Matt

[fsli]

when I home the machine and the axis reaches the home switch which is also the -limit switch the machine sometimes "limits out" and triggers an estop instead of homing

I would suggest going into the General setup screen and entering 10ms of debounce into both the "Inputs" and "Home" fields. If that doesn't solve it, then you should look at the wiring of the proximity switches, and in particular any place where the wires connect to other wires (Molex connectors, for example), or where they connect to the UC300-ETH input or power/ground terminals. If there are crimped terminals or ferrules, then make sure the crimps are still secure.

[torch]

I had the same issue on my UC300-ETH on UB1 some time after I changed my home/lim setup to overcome another problem (homing from wrong side of home sw. did not trigger lim when lim was hit. Probably had to do with faulty wiring of override signal for the OSSD safety circuit but I changed setup before it was discovered)

I change from separate home sw to using the lim as home. x+/x- in series for one port, and same for y and z.

It worked for some time but then I suddenly had the same problem as mattsshop. Some times it worked, some times it refused.

I did as fsil suggested and fiddled around with debounce but without success.

Did you manage to solve it mattsshop?

I ended up moving the cams for the home sw just 2mm away from the lim, and having the home sw on separate ports. That has been rock solid.

[mattsshop]

Hi torch,

I actually found my issue was loose grounds, after tightening all my ground wires and screws the issue went away.