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Electronics for CNC apparates

Last update: 31/07/2015

opto breakoutQuite often, to prevent damages to the personal computer in case of failures, in a cnc system is present a breakout board. This board is more professional compared to the previous one and has been created for those driver without any form of protection. 


All signals from/to the parallel port are opto isolated. Any opto isolator is followed by an inverted just to recall the exact level coming from or direct to the parallel board.

opto breakout

The particular disposition of the pins of the connectors make this board very useful to be used by Linux-Emc2 or Mach3 according to the fact that only one pin (pin 1) has been used to enable all the controllers. In this case there is surely a small general waste of current but such a solution will free three pins available to control external devices (through pins 14-16-17 of the parallel port) even using four axis.

opto breakout CNC
opto breakout CNC

(Original schematics has been revised) At first sight the schematic looks quite complicated but this is not true. For any pin there is a simple optocoupler (PC827 or two pc817) followed only by a trigger inverter. Only one power supply source must be used (from the USB port or using a 5V stabilized), NOT BOTH.


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