Talk:120 Family/@comment-37.219.147.86-20140908111458

Nice article, but one thing is missing. Safety.

I really not recommend to anybody to make some Mach3 MacGyvering with EM-stop on screen. Also it not really recommend that you have some +5VDC signal which goes through controller and stopping just enable signals on drives. When something happens, you just can't hit the "EM-stop" button on the screen with mouse. And if you can, that way is too unreliable to work for 99.99999% sure. Real EM stop is made with main (two serial connected) contactors and with two channel (manual reset) safety relay. It costs around 100$ and it is every dollars worth. Additional braking resistor for spindle's fast stopping at emergeny stop is also recommended if spindle have no electro-mechanical brake.

Even machine is small in this case, 6000rpm rotating part which is moving direction of tangent from chuck is not nice thing really. So avoiding accidental jaw opening you have make AT LEAST zero speed signal (from spindle drive, contact type NC) or door switch to block chuck opening solenoid. Real way is to use rotation detector which is connected to EM stop circuit. Rotating detection can be done also controller's PLC (if it is possible on Mach3 or EMC2), but it is not "official" way to do it. It is not I really not recommend Mach3 or EMC2 could use directly chuck's open/close solenoids, ever. Prefer use external buttons. Even more stable and professional systems there is always some kind of second safety system blocking solenoids when spindle is running. And Emco have pneumatic chuck, so remember wire EM-stop circuit pressure sensor (no pressure, stop whole machine).

Secondly it would be more than recommended you have some kind system to avoid accidental spindle start. Even door switch which blocks control signals raises machine safety 20 times.

I understand these are hobbyist machine, but use your head when you are thinking safety features. Use only (new) graded cables, use (right sized) fuses, use motor protectors, use thick enough cables, use cable ends make EM-stop circuit which is indepedent from controller. It is not that expensive, really.

Happy (and safety) machine building!!!