Wiring home and limit switches

[JAZZCNC]

If I use separate home switches for x,y,z & x2 linked directly to the bob

Ok first Not sure what your meaning here Dan with x2.? You only have 1 home switch per axis.

then have my individual limit switches + and - for x,y & z linked via the 24v circuit, where are the home switches to be positioned?
Originally I was going to use the home switches to act as limits on one end and have limit switches on the other but if I go for the setup above I'm confused as to where the homes should be placed.

Ok well if using Micro switch type then you still have the LIMIT switches at the ends, so 2 switches per axis.
The home switches are normally positioned just before the limit switches and so they home to a corner or end you would like to designate Zero position in Machine coordinates. That said they can be positioned anywhere you like really.!!
Personally I set my machines up so they home to corner then all my moves are always positive in machine coordinates. Mach is then setup to always home negative, this way it can't ever home in the wrong direction.

Now to answer the question of how do you put a home switch before limit switch.? It's easy really.!! . . . . You position The switch so gets triggered by a ride over Ramp not a hard stop. The ramp allows the switch to ride over while cutting and still have access to Limit switches at the ends. (Thou better other way round so static switch with mobile ramp triggering.!)
Home switch inputs are only watched or checked while homing so when it rides over the ramp it triggers, rest of time it's ignored.
This does mean the Home switches need an input of there own, they can still be wired in series but separate input to limits.

This is the reason why you can use Limit switches has home switches if sharing the same input or switch because the opposite is true while homing.!. . Limit's are ignored.
So if set to do this Mach treats the input differently while homing and instead of seeing the switch trigger and setting E-stop condition it now sets the current position has Zero Machine coordinate and resets Axis DRO's to zero.

Really micro switch type switches are not the best for Home switches unless very high quality due to them not being very repeatable. MS are fine for limits has they just work has ON/OFF triggers.
Inductive proximity switches or hall affect switches are better being much more accurate/repeatable and with contact less operation so they work without ramps etc.

Hope this helps clear it bit more.!

[Danielroyal25]

awesome, cheers Dean. That's what i was unsure of during normal operation the home switch being hit / operated, but that clears it up.
With X2 i just meant the home switch on the slaved X axis to get the gantry square (4 switches in total).
I have some Omron micro switches for the limits and Honeywell switches for the homes. Cheers!

[cropwell]

I got a bit annoyed with my machine stripping the delrin on the Z axis, so I decided to put limit switches on it. At the same time I put a couple of extra home switches to give home and limits on X++, X--, Y++, Y-- and Z++. While I was about it I put in status LED's (C'mon it's my toy )

The Limits had to go on a second BoB that I had that worked on 5v, so I basically OR'd each module to operate a reed relay, to give a Ground signal to indicate a limit switch had been triggered.

My main control board worked on 12v for the inductive prox switches and again each axis was OR dioded on the extra inputs for the X and Y axis's.

The only stupidity was the Override to kill the limit signal was a push to break switch. This means I have to hold it pressed while I reset Mach3 and keep it pressed while I jog off the limit. I am changing this to a SPDT switch which puts power onto a buzzer when the override is on. I know it is overkill but hey - I have retired and I need all the excuses I can find to stop other people finding me jobs.

OK - If anybody wants more detail I am happy to provide it, but right now I have to go and clean up in the Kitchen