How Many Limit Switches

[SPEEDRE]

I think I understand the function of limit switches but here's a dumb question. As I understand it there should be two limits for each axis, right? So the total is six. Two for X,Y, and Z each.

[buscht]

I would agree with your six switches. They could all be hooked up in series though, so you only need one input for all the switches. The purpose is to stop the machine, so you can easily see which switch is tripped and take appropriate action.

[Chris D]

Originally Posted by SPEEDRE I think I understand the function of limit switches but here's a dumb question. As I understand it there should be two limits for each axis, right? So the total is six. Two for X,Y, and Z each.

Rather than use two switches per axis, why not use two trip dogs (at opposite ends of the travel) to hit a single limit switch? It would save on the number of inputs needed for the CNC control.
Chris

[ger21]

Originally Posted by Chris D Rather than use two switches per axis, why not use two trip dogs (at opposite ends of the travel) to hit a single limit switch? It would save on the number of inputs needed for the CNC control. Chris

Typically, all the limits are wired in series and use only one input pin anyway.

[yukonho]

To compound this further, many people use one limit and one home switch per axis. The Z rarely has a - limit switch since tool length varies, hence the one switch at the top of the Z would be a home switch.
Colin

[SPEEDRE]

Well the I could ramp the limits and use the others as homeing, yes. All in series correct?

[ger21]

The home switches need to be wired individually, the limits in series if NC. Even though the homes switches are wired seoerately, they can still be used as limits as well.