How does the tool setter work?

I have my tool setter installed and working great. But I’m trying to understand exactly how it works - how it figures out the z offset for each different bit, just by pressing down until the green light comes on.

Can someone offer a relatively simple explanation?

You load the first tool. It touches the tool setter and finds a value, let’s say 10. When you zero with the xyz probe, the machine says “10” is the zero pout . When you change a bit to one that is, let’s say, shorter, it touches the tool setter and finds a value, let’s say 5, so it’s “offset” from the first bit to the second is -5, so the machine adjusts the “z zero” height to -5 for this next bit. All it’s doing it’s calculating the different stick out lengths of each bit you insert into the spindle.

Will the tool setter still work if the battery is low or dead?

Yes! The battery only makes the green led on the tool setter light up.