Home switches and Limit Switches

[TheBulk]

I've got Mach 3 sorted except for the limit switches.

I've got 6 limit switches - 1 for each end of each of the 3 axis' all wired up normally closed. 3 of those switches at the -- end I've got another wire connected up to a separate input on the normally open side of the switch.

So effectively I have two circuits each with a separate input into the G540. Normally closed for the limits and normally open for the home circuit.

The homing works so that is fine but I can't get the limit switch system to work. Am I doing something wrong or should I change the setup?

Thanks
Andrew

[ssutton]

I recently asked the same type of question here about limits and the G540. I was advised to connect all the limits together and wire them normally open and route them to 1 input on the G540, that way you only use 1 input. I did this and it has worked well for me. I also connected all of my home switches together and wired them to 1 input, this also worked well. The only exception to this is that I am going to add 1 more home switch to my table for my X axis so that I can square my gantry (I have 2 X axis motors) the new home sensor will have to have its own home sensor and input to the G540. If you search my post (about 2 weeks old) about this you will find allot of great information about homes and limits.

-Scott

[BanduraMaker]

http://www.cnczone.com/forums/diy-cn..._switches.html

Very helpful, thanks.

[cornbinder23]

Wouldn't wiring them up all normally closed in series make more sense?
That way if you have a bad switch or a break in a wire it would actually present itself as a problem.
And then all switches could share 1 input
just curious

JTCUSTOMS

[TheBulk]

It seems I've sorted it although I'm having an issue with my Z axis now. The default distance that the "Homing" moves back off the switch is not enough for the switch to be deactivated. I know that it should but I'm getting a "Limit switch triggered" message during homing of the z axis.

So the question is - Can I set the Z axis to move further away from the switch during Homing?

Andrew

[ger21]

It seems I've sorted it although I'm having an issue with my Z axis now. The default distance that the "Homing" moves back off the switch is not enough for the switch to be deactivated. I know that it should but I'm getting a "Limit switch triggered" message during homing of the z axis.

So the question is - Can I set the Z axis to move further away from the switch during Homing?

Andrew

There is no default distance. The machine backs off until the switch opens, then stops.

If you're getting limit switch errors, it's almost always due to noise. The simple remedy is to increase the debounce in general config to 2000-5000. some have found that a small capacitor will help as well.
The best solution is to remove the noise, usually caused by grounding issues.