I have a feed hold button, a cycle start button breaker and a spindle power cut off on my lathe's door. So things are very much safe as long as i think. It has some big steppers on it so if i unfortunately get hit by one of my axis sometime, i am sure there will be some broken bones. but i have seen guys of my age spending months on bed after breaking their ribs on skates on AXN. LOL!
Ok, thanks for everyone's comments and help. Giving up that estop issue, i would like to know about the limitations of modbus or serial communication with mach3.
I am going to start a new thread. please share your knowledge