Using proximity sensors for automatic Homing

Hi,

I am quite new to LinuxCNC. I couldn't find any other topic that answers the following:

Every time I launch a new config for a CNC mill, I have to home the axes again and again. A way around this will be kind of an automatic homing. I intend to integrate two proximity sensors at the home positions of X and Y axis.

Using these proximity sensors, can I achieve automatic homing? Can these proximity sensors act as both homing sensors and limit switches? If yes, please advice me on how to go about and achieve this.

Thanks

Regards

Yes they can be used for both homing and limits , although it is usual to use switches for limits and proximity for homing
as the homing point is usualy inside of the limit .

however linuxcnc has provision to use limit switches also as homing

linuxcnc.org/docs/html/config/ini_homing.html

to use the switch for both limit and home , use net both-home-x etc for the appropriate switch

Sorry, duplicate post!

Thank You.
After declaring the pins in custom _postgui.hal, don't we have to code it anywhere else to achieve automatic homing?
Further, if there is another post discussing the same, can you please post the link?

Regards

I dont think there it is fully automatic, you still have to click home all axes.
Also, I dont think you need to put anything in custom_postgui.hal for homing.

assuming your machine is called "main"
homing parameters are in main.ini
and the pins are connected in main.hal

here is an example from my main.hal (only one axis for simplicity)
as said earlier, replace home-x with both-home-x if you are using home and limit switch on same pin
also the "not" on the end inverts the signal
and from my main.ini
Basically on my X axis, I will usually be somewhere in the middle when I click home.
The negative search_vel makes it move in the X- direction until it finds the switch.
The negative latch_vel means it moves forward off the switch, then slowly moves back until it finds it again.
I put all my limit switches at 0, so that if I click home, when already in homed position, it doesnt wreck my machine.

I don't use limit switches, just homing and then axis sets the soft limits, which always work, except for a expermental setup I was using.
stepconf was a big help getting this set up for me, have you tried it?
Also, experimenting is the best way to learn how each change you make affects how the machine acts.

Thanks Guys!

It worked great. I have another query about homing. Suppose we connect home X, Y, Z to pins 10,11,15. Now each one is a different pin. With this configuration is it possible to create just 1 pyvcp button (say 'HOME AXES') that triggers each pin at the same time. Thus, one home button does it all. Can this be achieved w/o having to connect all sensors to the same pin?

Regards