auto-zero

Hey folks,

I would like to be able to auto-zero my router without going out to the machine. The touch plates that you can buy won't work because I don't want to have to attach a clip to the tool. I'm thinking of using a limit switch. I want to be able to stop in the middle of a long program, re-home, then rezero and continue running the program.........also it will help to speed up tool changes. The more automated the process the better....maybe even to the point of being able to have it written in the g-code if possible?? Sometimes the machine loses the zero by a little bit during long (100k lines plus) programs that run all day and night. It's probably noise in my wiring and the x and y use belts and can start to vibrate in the middle of a high speed roughing pass. I plan to re-wire the machine in the future but this is a fine tuning exercise for now. I'm getting great parts off the machine....I just know to check here and there especially if I'm running fast and there's vibration.

Anyway, I'm wondering if anyone has gone this route or has any ideas. The machine runs servos (5i25/7i77)

I'm not using tool offsets....yet. Plus that's not the problem....the machine drifts away from the actual set zero point during long programs that cause vibration and/or maybe system noise. I haven't tried to do this yet so there is nothing "not working" yet. I just want to be able to re-zero in the middle of long programs easily (or just check the zero to make sure there has been no drift) until I have a chance to rewire the machine.