Question Some issues with limits

I have some issues with limits. I wonder if somebody can quickly spot what might be wrong.

I double checked all axes wiring into the board, the specific Stepcraft 2/840 machine profile is loaded as required.

- In the diagnostics panel (see attached image), all three X limit -, Y limit -, Z limit - green inputs and all three X home, Y home Z home limits are permanently lit. I have disabled the soft limits to move the machine manually as expected but these limit conditions are stopping me doing anything unless the Override Limits button is used. I don't think that this is correct.

- A separate issue is that all the axes move in the wrong direction when homing. I corrected this by changing the Direction Positive checkboxes but I'm not sure why this is necessary if the profile is correct? If I then try homing with the Override Limits still active, then all three axes crash and continue to drive into the end stops, as expected...

If I toggle the limit switches on all three axes, there is no change to the LED statuses.

Regards.

Doug

So I removed the UC100 motion controller from the machine to see what inputs are lit when the machine is not connected. I still see the same limits made that were stopping me before. Confused.

All three X limit -, Y limit -, Z limit - green inputs and all three X home, Y home Z home limits are still permanently lit. At least this gives me some hope that the issue is related to the software configuration, not the machine...

It seems that the problem is with either X or Z or both limit switches. Annoyingly, activation of one limit switch to open circuit/off initiates ALL THREE hard limits.

When I linked out the XZ, they all cleared and allowed the Y to be toggled which is when I saw all three limits being active.

Toggling the Z limit changed from open circuit to about 1.4 kOhm circuit resistance intermittently; toggling X had no effect.

I am going to leave XZ linked out to still have the benefit of the Y limit switch rather than disassemble a machine which is working well mechanically but it looks like I will have to home the machine manually.

Thanks again to Rory who supplemented my meagre C&I diagnostic skills. He commented:

"Bad news that it’s the limits.

Good news that it’s not the control card / UC100 / UCCNC.

Honestly – don’t worry about fixing it.

The limits are largely not useful….

Run without them…

Simply go to

Axis setup
Each axis
Set the limit pins and ports to 0
Click in the white box – enter 0
Apply + save
Then they will go away.

Unless you’re doing offsets and fixture positioning etc… just zero her up over work and away you go"