Major components of the CNC control board
The figure below shows the components of a typical control board from Akriti Precision Systems.
- Starting from the left side, we see the following major components –
- Emergency Stop Switch – A kill switch, also known as an emergency stop (E-stop), emergency off (EMO) and as an emergency power off (EPO), is the safety mechanism used to shut off the machinery in an emergency, when it cannot be shut down in the usual manner.
- MCB/RCCB – All Akriti machines are installed with either MCBs or RCCBs to protect the machine against external electrical surges and as a power on/off mechanism under normal operation.
- VFD – A variable frequency drive (VFD) is a type of motor controller that drives an electric motor (spindle) by varying the frequency and voltage of its power supply. The VFD also has the capacity to control ramp-up and ramp-down of the motor during start or stop, respectively.
- SMPS – A switched-mode power supply (SMPS) is as an electronic circuit converting power with switching devices that turn on and off at high frequencies. IN this case the SMPS takes in AC current to produce a DC output for running the stepper motor drivers.
- Stepper Motor Drivers – Stepper motor drivers convert pulse signals from the controller into motor motion to achieve precise positioning. A motor driver takes the low-current signal from the controller circuit and amps it up into a high-current signal, to correctly drive the motor. It basically controls a high-current signal using a low-current signal.
- G-Code Interpreter – The main function of the G code interpreter is to interpret the NC code as a data source that can be recognized by the CNC machine or machine tool drive system and then communicated to the servo system.
- Control Board Output – Refers to the bunch of cables that are output of the control board and input to the CNC machine. It has cables carrying control signals back and forth between control board and CNC machine as well as electrical power(AC and DC) for the various motors and spindle.
The below image is an example of an Akriti Control box containing similar components as the board above.