....hmm....
Think you need to explain what you mean by "zeroing X,Y & Z".
I know this may seem obvious to you but are you asking the machine to zero the DRO's for each axis
Or are you asking the machine to home and zero each axis?
......................................
Attached is a "brain" that will do all the button presses you asked for. You will need to copy and paste it to your brains folder, and you will need to enable the brain via the "brain control..." under "Operator" .... you also need to click "reload all brains to get them to start working or restart mach3 (every time you do a change to the pins and ports etc configuration ... with the smooth stepper you really should restart Mach 3 so that the FPGA on the smooth stepper is reloaded with the pins settings and code)....
I'd also suggest you viewing the brain to make sure it's what you are after...
The best way to edit a brain is to go to the operator tab.... click on "Brain Editor..." and when it asks for a name, click cancel, and then once the brain editor loads... click open and open and edit the brain you want to edit.
You will also need to define your OEM Trigger Inputs (on the Ports & Pins / Inputs Tab) as follows:
Cycle Start --- OEM Trig #1
Feedhold --- OEM Trig #2
Stop --- OEM Trig #3
Rewind --- OEM Trig #4
Reset --- OEM Trig #5
Encoder to move X,Y,Z --- you will need to install an encoder on MPG#1 (and ref your pins on the ports & Pins / MPG tab).
Buttons to Select X (for encoder) --- OEM Trig #6
Buttons to Select Y (for encoder) --- OEM Trig #7
Buttons to Select Z (for encoder) --- OEM Trig #8
Buttons for Zeroing X --- OEM Trig #9
Buttons for Zeroing Y --- OEM Trig #10
Buttons for Zeroing Z --- OEM Trig #11
One little caveat.... you may need to invert the signals..... basically this is done in the brain by editing it.... where you see the box that says "No Operation signal pass", click on it twice and a box will open one of the options is "invert" this will flip the signal... sometimes bob's invert the signal.... and also it depends if you are using "make" (NO / normally open) or "break" (NC / Normally Closed) switches / buttons.
You may wish to consider something like these (they are all from china so available on various ebay around the world sites):
http://www.ebay.co.uk/itm/12V-OFF-ON-Momentary-Push-Button-Horn-Switch-Car-Light-Dashboard-Boat-SPST-/361345440863?var=&hash=item5421dddc5f:m:mihtRXVIAMpThMNLLOw0XwQor dealextreme or aliepress etc etc.... just to give you some ideas of a functional button.
Rob