Wiring Details

This page covers greater detail for setting up your Super Gerbil

Here’s our example wiring diagram with overlayed Area labels

A map of the Super Gerbil circuit board

Area 1A Connections – Limit Switches

In a nutshell, user-supplied power for limit switches is routed through all limit switches and the resulting current flow is opto-coupled to the Super Gerbil’s processor.

Bring your machine’s limit switch wiring to the Area 1A terminals.

The Limit switch and Control opto-couplers are powered via the VIN LIMITS/CONTROLS power screw terminals. Connect any voltage between 5 and 24V DC. The circuit’s been especially designed such that these power connections are unpolarised, so connecting plus and ground (GND) either way is fine.

Connect each limit switch (Normally Closed) to the appropriate terminal. For example, the Limit Switch that indicates the start (or end) of your X direction movement should be wired to the X limit switch terminal.
Note: the standard configuration for limit switches is Normally Closed. This design prevent accidents in the special case where wiring is broken and undetected. The disadvantage of Normally Open wiring is that you would NOT notice or detect a wire defect until the machine hits an end position and fails to stop. At least with a Normally Closed configuration, any wiring fault is immediately detected when the unit is turned on.

The Probe is the opposite of limit switches: Normally Open.

Hint: a probe switch can be easily made out of a piece of PCB board and a crocodile test wire lead. The G-code command ‘G38.2 Z-1 F5’ will auto probe the tool on the work piece or bed and just enter the PCB thickness as the Z offset, and you’re done!

Area 1B Connections – USB

Plug in the supplied USB cable, but do not connect to your PC yet.

Area 2 Connections – Output Terminals

Note: If you don’t have peripherals or want to install them later then you can skip this step.

MOSFETS are transistors designed for high current switching, and are used by the Super Gerbil to switch

  • Flood – an output port to control lubrication for CNC milling
  • Mist – an output port to control an alternative form of lubrication for CNC milling
  • Spindle – an output port to control the brushed DC rotary actuator on a CNC mill.
  • Tn – an output port to make mechanical tool selection in your tool changer
  • M6 – an output port, named after the M6 G-code, to activate your tool changer’s main engagement mechanism
Vin 24V – GND MOSFET PORTS – terminal

Note: although these output ports are labelled Mist and Flood, more generally, then can be used to control any auxiliary DC relay or motor/pump.
They are powered from the Vin screw terminal labeled on the silkscreen asVin 24V – GND Mosfet ports“. Connect the load on each appropriate terminal.

Note that all the above terminals use MOSFETs, and thus require protection from inductive spikes. Note that Super Gerbil includes an anti-parallel protection diode to protect the MOSFET. You don’t need to use your own protection diode, but you must use the correct +/- polarity of the terminals.

The spindle brushed DC brushed motor has 4 connections: M1 and M2 are the spindle motor terminals. The VIN SPINDLE MOTOR and Ground are the power inputs for the Motor driver board that sits in the socket behind the terminals.

Based on which Super Gerbil product you ordered, you will have either a 150W or a 750W Brushed DC motor controller. The 750W unit also has optional terminal pads on the motor driver itself that can be used instead of the screw terminals, however we recommend for clean installation to use the screw terminals on the Super Gerbil.

In any of the following cases, you’ll need to use the PWM opto-coupler port instead of the Brushed DC motor controller:

  • If your brushed DC spindle requires higher wattage than your Super Gerbil’s Brushed DC controller
  • If you have a Brushless DC motor (BLDC)
  • You’re controlling something else, such as a laser cutter PWM

If any of these applies, see the PWM opto-coupler details in Area 5.

Pololu DC Motor drivers: 2961 and 2994 (with 2961 in its socket)

Connect the VIN SPINDLE MOTOR terminal. Pay attention to the polarity. Connect the M1 and M2 spindle connections. If your brushed DC motor rotates the wrong way, you can swap your M1 and M2 wiring connections.

Area 3 Connections – Stepper Motors

Connect a power supply for your Stepper Motors to the left most terminal in Area 3, labelled VIN STEPPER MOTORS. The input can range from 6 to 35V DC.

SuperGerbil supports 4 wire stepper motors. You’ll need to identify the correct stepper motor wires before connecting them to the terminals. Manufacturers don’t consistently follow color coding standards, so please determine which stepper wires form the two coils yourself.

Gold Super Gerbil customers can use the stepper motor cables supplied, which can be trimmed to length as needed.

Area 4 Connections – Control Buttons

These connections allows you to add external push buttons for the Pause and Resume functions, a safety door switch for your CNC enclosure and the emergency button (Abort).

Note: The difference between the safety door and pause is that pause keeps the spindle and flood/mist pumps running while the safety door function stops everything until you resume the cycle.

While Super Gerbil works without the control buttons, it’s recommended that they be installed for safety and convenience.

Area 5 Connections – Spindle PWM port or VFD drive connection

You can use this opto-coupler port to drive an external peripheral like a Brushless DC (BLDC) motor driver, VFD or laser.

Apply either 5 or above 10 V to the screw terminal block. Use the jumper terminals above the screw terminal to select the on-board zener diode to regulate the level to 10V for VFD interface logic if necessary.

The 4 pin PWM header has a positive and a negative or complementary output. This can be used for lasers where it is common that the low signal switches on the laser and a 5V signal stops the laser beam. For BLDC drivers, typically 5V turns the motor on and 0 V turns it off.

If driving a laser, connect the Super Gerbil’s:

  • Negative PWM output to the IN terminal on the Laser power supply, and
  • GND pin to the GND or Ground terminal on the laser power supply.

Note: $ setting ‘$32 = 0’ is the CNC mode, ‘$32 = 1’ is the laser mode.

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