Main Connections Detailed
- Fuse - 5x20mm - Suggested 10A 5mm Diameter x 20mm Length. This fuse acts on the 12-36V motor power circuit.
- 12-36V DC power in. The DRV8825 Drivers can actually handle up to 45V, 36v however is the largest standard voltage power supply readily available. There is merit to running the Steppers at as high a voltage as practical (within reason) however 24V is plenty. The regulator for 12V fan power and 0-10V VFD output will work harder at higher voltages and has been selected for 36V max hence the 36V max on power supply.
- X Motor output, one motors coil pairs on the left side, other on the right side *1
- Y Motor output, one motors coil pairs on the left side, other on the right side *1
- Z Motor output, one motors coil pairs on the left side, other on the right side *1
- A Motor output (usually tandem with Y), one motors coil pairs on the left side, other on the right side *1 *2
- A Micro step M0 / M1 / M2, Generally On On Off.
- Z Micro step M0 / M1 / M2, Generally On Off Off.
- Y Micro step M0 / M1 / M2, Generally On On Off
- X Micro step M0 / M1 / M2, Generally On On Off
- Fan Connector, to connect your fan if using one, note voltage selector on JP8
- Spindle control output, GND & PWM runs a pulse width signal for controlling DC spindle speed controllers and alike, GND & 0-10 runs a 0-10V signal for controlling speed of a VFD. Direction goes high or low to suggest direction (not generally used)
- Limit Switch Inputs, GND is common across all switches, X, Y, &, Z go generally on the normally open side of limit switches. If using multiple limit switches per axis there may be two wires into each X Y & Z - The A limit pin is unused.
- External driver outputs, connect a DB 15 socket here or solder in wires manually to access the Enable, Step, and Direction outputs for each X Y and Z axis (enable pin is common across all)
- USB IO - you guessed it, stick the USB cable in here.
- CNC Control (Probe / Resume /Feed Hold / Estop) These have a common ground and are connected to buttons or switches in normally open config.
- Coolant Control, High when coolant is on, 5V logic, not allot of power on these outputs so use low power relay coils.
- Fault Logic -F = Feed hold on error, A = abort/reset on error, E feeds to a spare pin on the Arduino that could be setup as a separate error condition in code. For Motor driver faults to activate fault conditions, the jumpers 4, 5, 6, &/or 7 need to be connected.
- 19 Mounting screw holes - self explanatory again
- A Direction, will be duplicated from either X, Y, Or Z
- A Steps, will be duplicated from either X, Y, Or Z
*1 Our motors use Black + Green as one pair, and Blue + Red as the other. When connecting to the motor connectors, keep one pair on one side of the plug and the other pair on the other side of the plug - so for example left to right: Black Green Red Blue.
*2 The A motor often requires running in the opposite direction to the X or Y motor that its tandem driven with. (True for Heavy Mill & X Carve). If so then for this motor reverse one of the pairs of wires, so for this one left to right: Green Black Red Blue. Note the Green and Black have swapped position here.
Limit switch port (13) has 5 pins. We will ignore the 5th pin labelled "A" this is for future use.
Limit switches in GRBL are by default normally open, which is highly unusual but the standard with this software. Wire them either way as per below however if you go normally closed you will need to change a parameter in GRBL as per below:
- JP1 - Breaks Z Limit switch filter which is also on the MISO line and so can be troublesome if present while uploading code or bootloading via ICSP. Disconnect during programming via ICSP, reconnect for normal operation.
- JP3 - Connected if using onboard drivers, disconnected if using external drivers
- JP4 - Connect to enable X driver fault processing *3
- JP5 - Connect to enable Y driver fault processing *3
- JP6 - Connect to enable A driver fault processing *3
- JP7 - Connect to enable Z driver fault processing *3
- JP8 - Fan power, Connect in right position for 12V, left to match PSU voltage
- P8 - Not used yet
- ICSP - In circuit system programming header (for boot loading etc)
Driver current setting pots
- X Driver current limiting trim pot
- Y Driver current limiting trim pot
- Z Driver current limiting trim pot
- A Driver current limiting trim pot
These pots reduce current output of drivers when turned clockwise.
Dip Switch Settings
- 10: X Microstep M0 / M1 / M2, Generally On On Off, Setting the driver to 1/8th microstepping (8 Microsteps per step pulse received)
- 9: Y Microstep M0 / M1 / M2, Generally On On Off, Setting the driver to 1/8th microstepping (8 Microsteps per step pulse received)
- 8: Z Microstep M0 / M1 / M2, Generally On Off Off, Setting the driver to 1/2th microstepping (2 Microsteps per step pulse received)
- 7: A Microstep M0 / M1 / M2, Generally On On Off, Setting the driver to 1/8th microstepping (8 Microsteps per step pulse received)
- 18: Faults, No switch populated (Future Use, Contact us for more info)
- 20: A Direction, only one switch can be on, X,Y, Or Z. Which ever switch is on the DIRECTION signals for that azis will be duplicated to the A Axis, for our machines we select Y to tandem the direction from our Y axis over to the A.
- 21: A Step, only one switch can be on, X,Y, Or Z. Which ever switch is on the STEP PULSE signals for that azis will be duplicated to the A Axis, for our machines we select Y to tandem the Step Pulses from our Y axis over to the A.
OSX Note: Using later versions of 'Universal Gcode Sender', you will need to change the name of the serial port - UGS will only find serial ports starting with tty.usbmodem - as the usb chip on this card installs as "SLAB_USBtoUART" you need to change it by running the following code in your terminal app:
sudo ln -s tty.SLAB_USBtoUART /dev/tty.usbmodem0 (It will require your password).
GRBL Control Software Interface
There are many, the most simple and widely used is Universal G-Code Sender, grab the latest stable build not nightly build!