How to create simple tool changing script without homing machine?

Hi. I was looking for some tool-changing process on the internet but found out everyone using tool sensors in fixed places with machine homing. My router doesn't have a homing sequence and I'm doing it manually just simply go to my workpiece 0 0 0 with the keyboard and it works perfectly. I have a simple touch plate and want to use it like this. Placing it anywhere on the table going there with the keyboard. The tool touches the plate let's say Z-5.5 I'm going up taking the new tool touching the plate again and my machine changes Z to -5.5 with a new tool in moment of touch. Is it even possible in a simple way? Before i was doing it like this. Tool 1 -5 on plate tool 2 -11 on plate so i go Z6 and then zero Z. Has anyone done this sort of thing before? Or is there an easy way to do it and I'm just doing overthinking

Okay so i understand procedure now but how to add a button to axis gui with this procedure? I create button with pyvcp but how to connect gcdoe to it? Just paste it to .ngc and then what?

Okay I have already managed to make the button now I will try with the tool change procedure. Should anyone need it in the future because I have the impression that it is very hard to find such information.  First I had to add PYCVP and custompanel.xml in .ini and SOUBROUTINE_PATH =./path and in [HALUI] MDI_COMMAND = o<exchange> call
then connect button halpin from .xml in postgui.hal 
net remote-exchange halui.mdi-command-00 <= pyvcp.toolchange
Finally, in the exchange.ngc file I had to add o<exchange>sub and o<exchange> endsub at the end of the
 

Have you fixed it yet?

Today was struggling with M100 but by tomorow i should have working procedure to click to mesure> popup to chagne tool> mesure again> back to work. Just give me some time and i will post it here.

Okay, I knew it. I was totally overthinking. I simply do G38.3 to the sensor. set it as Z home do touch up on my stock zero and after changing the bit again G38.3 and Z home. Can I somehow home G53 from MDI to use it in macro or clicking on axis gui is the only way?

Lot of useful info in this video


Andy