Z Zero limit switch problem?

[Steamplates]

Hi All,

I've been doing quite well with the 'Bot this last few months but have several small issues I'd like to cure. I hope someone can help with this one:

I've got the Z Zero function working with the plate through C2 which is a breath of fresh air, but it has a problem at the beginning of the second, slower phase of spindle movement down to the plate.

Z just stops and I get a message 'Limit Switch Hit - Line 113'

All I can do is to click 'Resume' (or whatever the prompt is) and off it goes to finish zeroing up just fine. The Z axis is well inside it's physical movement limits. I find this a little confusing as from memory, and from actually looking at the Z axis, I can't see a limit switch like X and Y have. Maybe there is some kind of limit set up in the control software?

Can anyone shed any light on this please?

Regards

Steve

[Brady Watson]

This sounds to me like a ground (earth) issue, due to some kind of static. Has it been cold & dry in your neck of the woods? Is your machine chassis grounded/'earthed'? Are you running dust collection when this happens? How is the condition of your wiring - everything is done properly and appropriate strain relief applied? How about inside the control box @ the blue terminal strips? Be sure there are no bare wires touching as the result of stripping off too much before they go into the terminals etc.

Static charges can cause the limit switches to 'blip' and get triggered. You can turn off limit switch checking via the first line in the VN command. Just type it in & turn em off.

-B

[Steamplates]

Thank you Brady for your thoughts.

I carefully earthed the spindle etc. during the build using a completely seperate earth wire, but continue to use the earth clamp on the spindle when using the Z plate to Zero. I carefully tested all of this before I would trust it to Zero Z with a tool actually touching the plate on top of a job (by touching the plate on the tool when it is still in the air above the work) and it stops the Z feed just fine.

What confuses me slightly is there must be a good earth for the Z Zero routine to continue and stop the Z movement when touching the plate, but only after I got 'Limit Switch Hit line 113' and press 'Resume'. I guess your static theory fits in well there, although I can confirm I'm not running dust collection when zeroing Z.

But I do have the spindle inverter running in standby...hmmmm! I will try Z Zero with the inverter completely inactive to see if that makes a difference.

I will check eveything you have suggested for completeness.


Regards

Steve

[jerry_stanek]

I was having problems with the z routine and Frank had me do a UR and reload the setup. That solved the problem. It also was where it would go down and back up the give me a limit switch error but I couldn't resume.

[Steamplates]

Thanks Jerry,

I'm not suffering as badly as you did, at least I can 'Resume', it's just a minor PITA. I will follow up the idea.

Regards

Steve