Hi,
Ive measured the "reaction - time" of Mach3 with a Logicanalyser.
Here is the picture with the G31 movement. You see a delay of about 20ms between
switch trigger and movement stop of Mach3 (1,13GHz, 45kHz pulse, 500 debounce).
This time is nearly contant at homing, limit switch trigger and must be calculated for precision
measurement or probing. Only the emergency stop is a bit faster (10ms).
500mm/min/ 60 * 0,02s = 0,16mm error movement after trigger....
So, if you decrease your speed, your precision will be better.
Im making a macro with two speeds, first move very fast on the probe, then move back (1-2mm) and then a second, very slow move on the probe.
That will increase the precision into um range..

regards,
Wolfram
www.cnc-steuerung.com