ULN2803 CNC control interface for the isolated LPT

You can also use your CNC project running from the computer’s LPT port interface control card to the 74HC14 integrated circuit uln2803 are based on the opto-isolation provided by pc817

I decided to design your own master plate for CNC applications but not only 😉 (it is also used as a programmer for ATmega microcontrollers, as well as an early tester of simple programs control data output LPT port written in C + +)

CNC control interface board

There are 4 signal LEDs in the system, two of which give information about the presence of voltage 5 (LED1) and 12V (LED4). The next two indicate that relay 1 (LED2) and 2 (LED3) are working.

EXPLANATION OF BEGINNINGS:

– JP1-JP9;JP10,11,15,13,12; JP14,JP16,JP17 – outputs /LPT inputs respectively

– JP10; JP11 – 2x6GND designed for outputs from LPT port

– JP20 – ULN inputs (pins 1 and 2 control relay 1 and 2 respectively, while the other six inputs can be used any way)

– JP21 – ULN outputs

– JP12 – voltage connector 4x + 5V (eg to power controllers)

– JP12 – additional connector 4x GND (eg for powering controllers)

– X1 – 12V power input

– X2 – relay 2 connector

– X3 – relay 1 connector

CNC interface board circuit schematic etc. files: