This pcb is for simplifying the wiring connectivity between the PC's parallel port and the CNC electronics. There are a number of "Break Out Boards" or BOB out there that are misnomers. A BOB is simply a connector and terminals for connectivity. This interface provides the same functions as a BOB, but enhances and simplifies the rest of the wiring. This board is compatible with the modular single channel driver boards. LED1 through LED5 PROVIDE INDICATION for home and/or limit switches wired via screw connectors LS1, LS2, and LS3. Connectors AUX1 and AUX2 are for driver outputs that can be used to control mechanical or solid state relays. LED6 indicates the state of the AUX1 driver. LED2 indicates the state of the AUX2 driver.
|Pin 1 Aux1||Pin 10 LS1 1 Switch|
|Pin 2 X Step||Pin 11 LS2 2 Switch|
|Pin 3 X Dir||Pin 12 LS2 1 Switch|
|Pin 4 Y Step||Pin 13 LS3 1 Switch|
|Pin 5 Y Dir||Pin 14 Enable|
|Pin 6 Z Step||Pin 15 LS1 2 Switch|
|Pin 7 Z Dir||Pin 16 Pad 16|
|Pin 8 A Step||Pin 17 Pad 17|
|Pin 9 A Dir||Pins 18-25 GND|
Recommend Switch Wiring
The below layout is one of the easiest to implement and probably is one of the best supported by various pieces of software. It utilizes two normally closed switches on each axis, one for home and one for limit. The home switch is located on one end of the axis movement and the limit on the other end. The home switch is then defined by the software direction to seek home, which is in the specific software setup. Thus the below diagram depicts three axis of home and limit wiring and one emergency stop switch. The common wiring point is the return (0v-gnd-common with the four connections to the parallel port pins for input, with the emergency stop being pin 10, and the axis switches wired to pins 12, 11 and 13. ) Wire the return as shown and do not rely on metal connectivity of a machine. When the switches are not activated, the inputs of those pins are LO. Bumping a switch the input for that axis would go HI. The Emergency Stop would activate HI also. This layout is compatible with MACH3, TurboCNC, EMC and CNCpro.