General Notes

The controller card, like the software, is under continuous development, and new features and other changes often occur. The actual component and connection layout of your pcb may differ from that shown here, certainly the firmware version has been superceded. Please check the position of the connections against your pcb. The pcb silk screened annotation should be correct.

To test the controller and software, it is only necessary to connect the serial cable and power supply. You do not need to connect any stepper motors, or ancillaries, but you must connect the Estop terminal to gnd. The software should then detect the controller, provided you set the correct serial port, etc. Jogging, or running some G-code should show the on-screen coordinates changing

Because of the the risk of crosscoupling between the motor connecting and signal wires, it may well pay you to experiment with capacitors across the switch contacts, screened signal wires, and pull up or pull down resistors. Ensure that any power/motor drive cables are routed away from the signal wires.

It is also worth while making one common ground for the pcb, motor driver boards and the mass of the machine itself.

Power Supply

The DeskCNC Controller board requires an 8 to 20 Volt DC supply (not included) through the 8V-20V DC terminal. The 3 terminal connector is located at the bottom of the illustration here. The +5V terminal is a regulated output.  When power is applied, the green LED will glow. Do not reverse polarity as the board will be destroyed instantly.

Com Port

The DeskCNC Controller connects to the computer serial port through a standard 9 Pin serial cable (not included). If your computer uses a 25 pin serial connector, make sure the Transmit (Tx) line goes to pin 2, the Receive (Rx) line goes to pin 3, and the Ground line goes to pin 5.

Gnd

Ground Terminals. All Gnd terminals are the same.

+5V

+5V Terminals. All +5V terminals are the same.

Home (X, Y, Z, A)

Normally Closed Home Switch Inputs. When grounded during a homing operation, homing of the associated axis will start.

ESTP

Primary Limit Switch Input. This terminal should be grounded for normal operation. When a normally closed limit switch is opened, the controller will send an Emergency Stop (E-Stop) signal to the software. Interpretation of the g-code file will then stop, and all axes movements will immediately stop. If you are not using limit switches or an emergency stop button, then you will need to connect this terminal to gnd.

Lim

Secondary Limit Switch Input. Use with normally open switches. This terminal should be left ungrounded for normal operation.  Attaching the optional Digitizing Probe to this terminal and gnd allows touch probe digitizing of 3D Models.

(X, Y, Z, A) Dir

Connect to the DIR line of the associated stepper or servo motor driver.

(X, Y, Z, A) Step

Connect to the STEP line of the associated stepper or servo motor driver.

Mst

Mist coolant output. A logic high (+5v) is output when the M code 'M07' (Mist On) is interpreted from the g-code file. A logic low (0 v) is output when 'M09' (Coolant off) is interpreted.

Fld

Flood coolant output. A logic high (+5v) is output when the M code 'M08' (Flood On) is interpreted from the g-code file. A logic low (0 v) is output when 'M09' (Coolant off) is interpreted.

CW

Clockwise Spindle output. A logic high (+5v) is output when the M code 'M03' (CW On) is interpreted from the g-code file. A logic low (0 v) is output when 'M05' (Spindle off) is interpreted.

CCW

Counter Clockwise Spindle output. A logic high (+5v) is output when the M code 'M04' (CCW On) is interpreted from the g-code file. A logic low (0 v) is output when 'M05' (Spindle off) is interpreted.

PWM

PWM Output for spindle speed controls needing a PWM signal. The PWM duty cycle will vary from 0 - 100% depending on the [SPINDLE] parameters set in the DeskCNC.Ini file. The frequency is about 2.4kHz.