USB-MC is motion controller designed for use with popular Mach3 CNC control software in Windows XP, Vista, 7, 8, 8.1 and 10 operating systems with 32-bit (x86) and 64-bit (x64) architectures. As external controller, it brings various improvements in comparison to using Mach3 software over parallel port. USB-MC does not require installation of Mach3 LPT driver.

Motion controller USB-MC takes over all real-time tasks that require precision timing. Thus, computer CPU is less loaded, so that Mach3 now can work on less powerful desktop, laptop, and even tablet computers. Considering that controlling task does not need high performance computer, the price for complete control system can now by considerably reduced.

At the same time, much higher output frequency for step signal (up to 250 kHz) is achieved and much better quality of output than it is possible with parallel port regardless of performances of used computer.

The parallel port is becoming less and less common and is almost obsolete. Newer computers often do not offer this port. USB-MC is using USB for communication and USB port is present on all modern systems.

A large number of functions have been added and existing are improved. PWM output can have much higher frequency and higher resolution, PWM power compensation in relation with feedrate is added, implemented hardware MPG mode, more detailed debouncing adjustments for all input signals, and much more.

USB-MC motion controller has 16 digital outputs and 14 digital inputs in comparison to 12 digital outputs and 5 digital inputs that are available from parallel port. In addition, USB-MC has analog input which is not possible to realize via parallel port.

Additional inputs and outputs are available via appropriate connectors, and via add-on input/output boards that can be easily connected to USB-MC motion controller.

For connection of USB-MC motion controller with PC, it is important to use high quality cable, as short as possible, preferably not longer that 1.5m.

NOTE: USB-MC controller is powered from USB port so in its primary function external power supply is not necessary. However, external power supply is required if input/output add-on card UIO-1 is used because this card requires higher voltage than 5V that is available from USB port.

Supported Mach3 functions

  • all jogging modes
  • spindle PWM out, adjustable frequency 10 Hz – 200 kHz
  • spindle index input, adjustable divider
  • spindle step/dir axis
  • spindle relays (M3, M4 and M5)
  • coolant relays (M7, M8 and M9)
  • ESTOP input
  • MPG (encoder) inputs, all Mach3 MPG modes + hardware mode
  • freely assignable functions to any of inputs and outputs
  • adjustable active signal state (low/high) for all inputs and outputs
  • homing/referencing (single axis and multiaxis)
  • hardware limit switches
  • softlimits
  • limits override, auto/manual/external
  • charge pump outputs, adjustable frequency (12.5 kHz and 5 kHz)
  • slave axes
  • probing function (G31)
  • laser M10p1/M11p1, e5p1/e5p0 fast outputs (#1-6)
  • laser PWM, power compensation (PWM duty cycle can change in relation to velocity of movement), adjustable arbitrary relation curve
  • laser PWM, gate by M10/M11
  • laser gray scale (8-bit) engraving - NEW
  • shuttle mode, adjustable acceleration time
  • detailed adjustment for debouncing of all input signals
  • offline mode
  • threading on lathe using Mach3turn, G32, G76
  • THC function (integrated & external controller support)
  • Advanced THC options: Low pass filter, Kerf detect, THC lock if voltage out of range, THC lock from g-code - NEW

Not supported

  • Backlash compensation

Image gallery

Technical specifications

Function Description
Number of axes 6
Number of digital outputs 16
Number of digital inputs 14
Maximum STEP signal frequency 250 kHz (option 125 kHz)
STEP pulse width 2 μs (option 4 μs)
PWM output frequency 10 Hz – 200 kHz
PWM duty cycle resolution 16-9 bits, depending on frequency; 16 bit for f ≤ 2kHz
Frequency of signal on Index input ≤ 10 kHz
Pulse width on Index input ≥ 100 ns
MPG/encoder input (x4) frequency ≤ 10k steps/sec
Digital input/output type TTL, 5 V, Pull-up resistors 4.7 kΩ on all inputs
Maximum current on digital outputs 32 mA
Number of analog inputs 1
Analog input range 0 – 3.3 V (0 – 5 V via IO card)
Charge pump outputs 2
Charge pump frequency 12.5 kHz or 5 kHz
Communication with PC USB - data buffer about 1 s for stable communication
Power supply from USB port
External power supply (optional) 8 – 24 VDC / 250 mA (UIO-1 card requires 15 – 20 VDC)
Dimensions 92 mm x 84 mm x 27 mm
Weight ~ 60 g

NOTE: Shown specifications are subject to change without prior notice


Document Description
pdfUSB-MC User's manual USB-MC user manual and Mach3 plugin installation guide

pdfUSB-MC THC operation

Plasma torch height control using USB-MC motion controller - NEW

USB-MC motion controller, in addition to support for external THC regulator, also has integrated THC regulator that is possible to utilize by connecting appropriate voltage sensor to the analog input of USB-MC controller

USB-MC Laser raster engraving

Coming soon

Gray level raster engraving - NEW

Engraving of raster images using laser – 8-bit pallet (256 shades of gray) is supported. When this option is turned on, axis A is used for control of laser power, i.e. commanded "movement" of A axis directly translates to duty cycle of the PWM output. Needed G-code should be generated from a bitmap picture using one of the available programs for that purpose.

USB driver and installation instructions

Document Description


zipWinXp old ver.zip

USB driver

In most cases, if Windows 7 or newer operating system is used, Windows will automatically find and install required driver so that manual installation should not be needed. Otherwise, if Windows does not find the driver, it will ask for the location on local computer to read it from. In that case download and unpack one of the available drivers.

pdfUSB Driver Installation guide Instructions for USB driver installation for computers with Win XP operating system

Mach3 Plugins & Custom Screens

NOTE: Mach3 plugin contains integrated latest compatible version of firmware for USB-MC motion controller

Date Plugin version Description
October 2022. zipusbmc_drv_pl1.19_fw1.22.zip Firmware v1.22 & Plugin v1.18
- Correction: incorrect Probing target point when machine coordinates view is active
June 2022. zipusbmc_drv_v1.22.zip Firmware v1.22 & Plugin v1.18
- Fixed error: with internal THC regulator, Nominal torch voltage is sometimes reset to zero after restarting Mach3
- Fixed error: if ArcOK signal is not used for THC but instead option "Ports&Pins/MillOptions/Allow THC Up/Down control..." is used then regulator does not always wait the Pierce Delay time uppon every arc ignition by M3 command
- SoftLimits for angular axes can now be disabled by using appropriate option in General config
- Disabled slow zones with SoftLimits for g-code motion and corresponding option removed
March 2021. zipusbmc_drv_v1.21.zip Firmware v1.21 & Plugin v1.17
- Error corrected: when threading by using G32/G76 commands, output Output1 is deactivated after the first threading pass
June 2019. zipusbmc_drv_v1.191.zip Firmware v1.19 & Plugin v1.16
- Added option to control THC nominal voltage by using rotational encoder (Special Functions)
March 2019. zipusbmc_drv_v1.19.zip Firmware v1.19 & Plugin v1.15
- Added option for manual THC mode
- Nominal THC voltage can now be entered directly to appropriate DRO field on Mach3 screen
March 2019. zipPlasmaAohmsUSBMC.zip New customized Plasma screen with added LED indicator for manual mode. Compatible with Firmware v1.19 & Plugin v1.15 and higher
November 2018. zipusbmc_drv_v1.17.zip

Firmware v1.17 & Plugin v1.13
Added new advanced options for THC: Low pass filter, Kerf detect, THC lock if voltage out of range, THC lock from g-code

November 2018. zipPlasAo_112018.zip Customized screen for Mach3 Plasma mode, compatibile with Firmware v1.17 & Plugin v1.13 and higher
July 2018. zipusbmc_drv_v1.15.zip Firmware v1.15 & Plugin v1.12
Bug fixes:
- When G31 probing operation is started, incorrect warning that move is outside SoftLimits is issued if work offsets are used
- G-code current line marker sometimes moves uncontrollably while performing some Mach3 operations
- Limit/estop switches, if they are of low active type, are sometimes erroneously detected as active upon pressing RESET button
- Mach3 turns of SoftLimits upon calling Verify function. Workaround is implemented to return previous state of SoftLimits after Verify function is completed
April 2018. zipusbmc_drv_v1.13.zip

- Improved operation of soft limits slow zones
- Added new option to turn off soft limit slow zones for g-code motion
- Added new option for plasma "Force wait for THC_ON after M3" that serves as a workaround for Mach3 illogical behavior (timing bug) when waiting for arc ignition

January 2018. zipusbmc_drv_v1.11.zip

Bug fixes / problems corrected:
- Fixed bug in Probe function that used to cause errors in controller operation on some systems
- Limit switches not detected under certain conditions during g-code execution
- SoftLimits (if turned on) are sometimes activated during homing sequence, i.e. just after one axis homing and before start of next axis homing

November 2017. zipusbmc_drv_v1.07.zip

-added new option for adjusting maximum STEP signal frequency to 125 kHz (pulse width 4 µs)
-added new option for dereferencing all axes on disconnect
-fixed bug with incorrect polarity of DIR signal for slave axis

August 2017.  zipusbmc_drv_v1.06.zip

New option for laser grey level raster engraving (8-bit). When this option is turned on displacement of A axis directly controls PWM output duty cycle
SoftLimits: settings for SoftLimits of disabled axis are now ignored
Homing: fixed bug with calculation of homing speed as a percentage of maximum specified speed for the axis

March 2017. zipusbmc_drv_v1.05.zip

Added support for external and integrated THC regulator – BETA version
This archive contains user screen customized for Mach3 Plasma mode

May 2016. zipusbmc_drv_v1.02.zip Initial version


BLOG - Possible origins of connection problems between USB-MC motion controller and PC


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