Z Stop Calibration


I have an older M200 and would like to know what controls (or where is) the Z stop for the platform down direction.
When I finish a print I get the “Beep” and the platform is lowered until it gets another “Beep” and stops on its own well above bottoming out.
If I “Pause” a print and decide to “Quit” the print the platform will go down until it bottoms out and grinds quite a bit before it stops and no “Beep” is heard. It doesn’t sound good and doesn’t seem that it should be programed this way but would like to know if this is normal or can the Z stop be adjusted to prevent this?