Description
The USB MACH3 4 Axis Controller is a USB motion-control interface for Mach3-based CNC systems using stepper or servo drives. It supports coordinated control of up to four axes, a maximum step-pulse frequency of 100 kHz, isolated machine inputs and relay-control outputs, an MPG handwheel connection and a 0–10 V spindle-speed command. It is intended for CNC routers, milling machines, lathes, engraving machines and retrofit control cabinets where a standard USB connection is preferred over a legacy parallel port.
The board requires correct Mach3 configuration, the supplied RnRMotion.dll plug-in and an external 24 V DC supply for the isolated field-side functions. The controller outputs step-and-direction signals to external motor drives; it does not power a stepper or servo motor directly.
Controller Overview and Connections
The images below identify the controller terminals, principal connections and typical system wiring. All original product links and downloads are retained further down this page.
| Parameter | Specification |
| Controller type | USB motion-control interface for Mach3 |
| Controlled axes | Up to 4 axes |
| Maximum step-pulse frequency | 100 kHz |
| Motor-drive interface | Step-and-direction signals for external stepper or servo drives |
| General-purpose inputs | 4 isolated inputs |
| General-purpose outputs | 4 isolated relay-drive outputs |
| Spindle-speed command | 0–10 V analogue output |
| Handwheel support | 10-pin MPG connector |
| External field supply | 24 V DC required for isolated external-port functions |
| SKU Number | 1112000 |
| All product data (pictures, dimensions, tables, drawings) are provided as received from the supplier; we exclude liability for their accuracy or completeness. | |
Key Features
- Four-axis motion control: Connect up to four external stepper or servo drives for X, Y, Z and A-axis operation.
- 100 kHz pulse output: Suitable for a wide range of CNC stepper and servo-drive configurations within the controller’s specified pulse limit.
- Machine-safety inputs: Supports limit switches, homing switches, emergency-stop input and automatic tool-setting input.
- Spindle control: Provides relay-control functions and a 0–10 V command for compatible inverter or VFD speed control.
- MPG support: Dedicated connector for an electronic handwheel with axis selection and step-multiplier inputs.
- USB isolation arrangement: An external 24 V DC supply powers the isolated external-port section and improves separation from the PC USB side.
- Status indication: On-board LED provides a basic connection-status indication.
What You Need Before Installation
- A Windows PC with Mach3 installed and correctly licensed or configured for testing.
- The RnRMotion USB motion plug-in copied into the Mach3 PlugIns folder.
- The supplied Mach3Mill.xml configuration file, or a carefully configured existing Mach3 profile.
- A regulated 24 V DC power supply for the isolated external-port functions.
- Compatible external stepper or servo drives accepting step-and-direction control signals.
- Shielded signal cabling and correct grounding practice, especially near spindle, VFD and motor-power cables.
Mach3 Plug-in and Profile Setup
- Install Mach3: Complete the Mach3 installation before connecting and configuring the motion controller.
- Install the motion plug-in: Download RnRMotion.zip, extract RnRMotion.dll and copy it into the Mach3 PlugIns folder.
- Connect the controller: Connect the board to the PC by USB and confirm that Windows detects the USB device.
- Select the motion device: Start Mach3, select the RnRMotion controller when prompted and enable “Don’t ask me again” after confirming the correct device.
- Load the machine profile: Download Mach3Mill.zip, extract the XML file and place it in the Mach3 root folder.
- Verify every machine setting: Check axis direction, steps per unit, velocity, acceleration, input polarity, homing, limits, outputs and spindle scaling before powered movement.
⚠️ Important: A downloaded XML profile is only a starting point. Motor tuning, axis direction, input logic and spindle settings must be verified for the specific machine before operation.
Typical Wiring Arrangement
An additional 24 V DC source is required for the isolated external-port functions, including machine inputs and spindle-control connections. Keep USB and low-voltage control wiring separated from VFD output, spindle and motor-power cables.
Electrical-noise warning: Use shielded signal cables near high-frequency or high-voltage wiring. Route control cables away from VFD output and motor-power cables to reduce induced interference and the risk of controller damage.
Inputs, Outputs and Spindle Control
The four general-purpose isolated inputs can be assigned in Mach3 to functions such as limit switches, emergency stop, probe/tool setter and homing. The four isolated output channels can command suitable external relay circuits for functions such as spindle run, direction, coolant pump or auxiliary equipment.
The 0–10 V output is intended as a speed-reference signal for a compatible inverter or VFD. The VFD must be configured to accept an external analogue speed command, and Mach3 spindle-pulley settings must match the actual spindle and inverter limits.
⚠️ Safety note: Do not use software inputs or relay outputs as the only emergency-stop safety measure. A machine emergency-stop circuit should remove hazardous motion or spindle energy through an appropriate hard-wired safety arrangement.
MPG Handwheel Connector
The 10-pin ribbon connector supports a manual pulse generator for axis jogging and incremental movement.
- 5V and GND: Supply for the MPG encoder electronics.
- X, Y, Z and A: Axis-selection inputs; the selected axis pin is connected to GND through the selector switch.
- A-CH and B-CH: Quadrature encoder channels from the MPG wheel.
- X10 and X100: Increment-multiplier selection; with neither selected, the default is X1.
5 V limit: Do not apply more than 5 V to the MPG connector inputs. Excess voltage can permanently damage the controller.
Complete Wiring Diagram
The following drawing shows the supplier’s complete connection layout. Confirm every terminal against the board markings and manual before energising the system.
Controller Dimensions
Use the supplier drawing below when planning enclosure space, mounting position and cable access.
Commissioning Checklist
- Test the controller with motor-drive enable circuits disabled or with the machine in a safe low-energy state.
- Confirm the emergency-stop circuit before testing axis movement.
- Verify axis direction and limit-switch polarity one axis at a time.
- Start with conservative velocity and acceleration values in Mach3 Motor Tuning.
- Check that the commanded and measured spindle speeds correspond before production use.
- Back up the working Mach3 XML profile after commissioning.
FAQ frequently asked questions
Does this board drive motors directly?
No. It sends step-and-direction signals to separate stepper or servo drives, which then power the motors.
Is a 24 V supply required?
Yes. An external 24 V DC supply is required for the isolated external-port functions described by the supplier.
Can it control spindle speed?
Yes, through the 0–10 V speed-reference output when used with a compatible and correctly configured inverter or VFD.
Which Mach3 plug-in is required?
The board uses the RnRMotion.dll motion plug-in supplied in the download link on this page.
Can I connect an electronic handwheel?
Yes. The dedicated 10-pin MPG connector provides encoder, axis-selection and increment-multiplier connections.
Is the supplied XML ready for every machine?
No. It is a configuration starting point. Every axis, input, output, limit, homing and spindle parameter must be checked for the actual machine.
Downloads
CNC USB Controller STB4100 Manual
CNC USB Controller RnRMotion Plug-in