This picture shows how to connect computer to CNC engraver.
Modern computer has USB ports (LPT, COM are obsolete).
There must be embedded controller between PC USB port and motor drivers.
USB controller has it own microcontroller. It converts USB protocol to electrical signals.
We have developed small controller which can drive three step motors.
This means that USB controller is suitable for any three axis CNC engraver / router.

- USB controller power supply is 230V AC.
- There is power relay for switching on and off spindle motor. It can commutate max. 2kW
- Once started automatic milling form SD card USB controller can operate without PC connection.
- There are six digital inputs for limit switches.
- Outputs to motor drivers are STEP / DIR.

Outputs to stepper motor drivers can drive directly LED. Drivers inputs are optocouplers so CNC controller can be connected directly to these inputs without any resistors.
Inputs for end position limit switches are digital. Normal closed switches can be connected to these inputs. When switch is open this means that end position is reached.
Terminals "spindlе supply" on the right side of the picture is normal open contact of relay. Relay is 12A 240Vac.
It is suitable for swithcing motors up to 2kW.
Also there is aux. outputs - 12Vdc. This output can be used for power cooling fans, lights etc.
Maximum consumption is 130mA.

Techincal data:

- 3 axis controller for stepper motors;

- USB connecton;

- 30uS pulse and pause width;

- 6 digital inputs for 6 end limit switches;

- SD card support for running G-code withcout PC connection;

- Power contact for spindlе motor;

- 12VDC 130mA output for supply cooling fans, light etc.