M31 Motion Control Setup Manual

The M31 is a compact, industrial motion controller designed specifically for MachPro CNC systems. It links your MachPro control PC to your drives and motors over Ethernet and supports both EtherCAT and traditional step-and-direction control, giving you flexibility in how you build or retrofit your machine. With support for up to 12 axes, the M31 scales from small routers and mills to large, multi-axis specialty machines, while maintaining synchronized, precise motion across all channels. It’s engineered as the motion “engine” of the MachPro platform, providing a stable, factory-certified hardware layer between your Windows control PC and the field hardware on the machine.

 WARNING!
Improper installation of this motion controller can cause DEATH, INJURY or serious PROPERTY DAMAGE. Do not attempt to install this controller until thoroughly reading and understanding this manual.

1 Introduction

Reference Diagram

Use the diagram below as a reference throughout the manual.

Specifications

Below are the specifications for the M31 motion controller.

Please observe the max voltage on each pin. Some pins are 24v compatible, some are 5v, some are 3.3v, and some are 0v. Exceeding their max voltage will cause serious damage to the M31 Motion controller. 

Item	Specification
Input Power	24VDC
Max Power Consumption	48W
Motors
Stepper Channels	6 motors
Step and Direction Axis Control	5V Single Ended and Differential
Connection	Terminal Blocks
Max Pulse Speed	1.6 MHz
Ethercat Network
Device Types	Servo Motors, Stepper Motors, VFDs, I/O Modules, etc
Max Devices	30
Max Motors	6 motors by default (8 and 12 motor options available)
Quadrature Encoder Channel	1
Connection	Terminal Blocks, 5V Differential
Max Frequency	1.6 MHz
Spindle	1
Opto-Isolator Outputs	Forward and Reverse Open Drain / Open Collector outputs
Analog Speed Signal	0-10VDC
Encoder Feedback	Yes
Digital Outputs	8 (PNP Sourcing)
Voltage	16 - 24VDC
Max Current	250mA
Pulse Wave Modulation (PWM)	Not yet available
Inputs	16 (PNP Sourcing)
Voltage	16-24VDC
Input Current Range	3 - 6mA
Isolated	Yes
Enable Circuit	2
Hardware Enable	Relay Dry Contacts, 5V Enable or 24V Enable
Drive Enable	Relay Dry Contacts
Emergency Stop Circuit	Normally Closed Connection
Ethernet Port	10/100 MHz
Dimensions	7.125"(L) X 3.75"(W) X 1.875"(H)
Optimal Temperature Range	32° to 100°F (0° to 38°C)
Humidity	30% - 60% RH

Status LEDs

Each LED has a single color.

LED	ON	OFF
Power	Green - M31 is powered	No Power
CPU	Blue blinking - M31 CPU is active Standby Mode (blip a little more than once a second) Run Mode (double blip/heartbeat) bootloader (rapid flash)	CPU is not enabled
E-Etop	Red - E-Stop pressed, or the E-Stop circuit is incomplete	E-Stop is not active
Hardware enable	Orange - hardware enable is on	No hardware enable signal
Drive enable	Orange - drive enable is on	No drive enable signal
Spindle fwd	Green when spinning forward
Spindle rev	Green when spinning in reverse
Drive alarm	Red - one or more drives are in alarm state	All drives report good

Tools Required

A small, flat head screwdriver is needed for the I/O terminals. 

Recommendations

If your system is running 480 VAC we recommend using line filters before the servo drives and VFDs. At higher voltages they generate a lot of electrical noise which can affect the logic circuits in your system.

The M31 Motion Controller and the drives can supply 24VDC, but they do not have a lot of output capacity. We recommend adding separate 24 VDC power supplies. Specific suggestions for success:

1. Use separate 24 V supplies for I/O and field loads if current is high.

2. Tie all 0 V terminals to a single 0 V / ground bar in the main cabinet.

3. Bond this bar to PE at one place.

4. Keep motion controller and drive I/O referenced to this same 0 V bar.

5. Use isolated I/O for external panels and long cables.

This approach prevents large ground potential differences while still offloading the 24 V outputs on drives and motion controllers.

Firmware Update

On your first start of the MachPro software, it will check to ensure that you have the latest firmware for the M31 motion controller. If not, you will see an update screen.

Follow the prompts to update the M31 firmware. When it has completed the process, it needs to reboot the M31, and it will prompt for your approval to do that. Once the M31 is running again, and both the Firmware and FPGA are current, close the M31 Upgrade window.

Restart the MachPro software to ensure smooth operation.

Hardware Startup

To power the M31, you must supply 24VDC to the power connection located at the top right of the board as shown below. The LED labeled PWR will be green when 24VDC is supplied.

Emergency Stop (E-stop Circuit)

The emergency stop connector is located in the upper right corner of the M31. When the emergency stop terminals are connected together, the red E-Stop LED turns on and the controller can then enable. This is a safety circuit that immediately stops motion when activated.

Important: The M31 motion controller will not operate unless the Emergency Stop (E-Stop) circuit is complete.

Multiple E-Stop Devices

• Connect all E-Stop devices in series in the same E-Stop circuit.

• In a series circuit, any open contact will open the entire E-Stop circuit.

Adding an E-Stop Button to the M31 Board

• Use an E-Stop button that does not require its own supply voltage.

• This type is often called a “voltage-free” or “dry contact” E-Stop.

If the E-Stop button requires a supply voltage:

1. Wire the E-Stop button to a relay input.

2. Use the relay output contacts in the E-Stop circuit.

3. Ask a qualified electrician to design and verify this wiring.

M31 Emergency Stop Input Mapping

• The Emergency Stop input is mapped to M31 1DI.ESTP.

• When configured correctly, opening the E-Stop terminals will disable the system.

• The system will only operate when the E-Stop circuit is closed and healthy.

Hardware and drive enable overview

Before you use hardware enable or drive enable, configure the emergency stop circuit.

The M31 includes two control circuits: hardware enable and drive enable.
These circuits remain inactive until you configure the emergency stop (E-stop) circuit.

Use the default settings unless your application requires changes.

Accessing the enable settings

1. Open Configure > Control.

2. Select the Settings tab.

Available options

In the Settings tab, you can:

• Set the delay between hardware enable and drive enable.

• Choose which outputs turn off when the system disables.

Configure the Dedicated Network Interface

The M31 motion controller connects to the control computer through a static IP Ethernet connection.

Follow the Microsoft guide below to manually set your network adapter to communicate with the M31:
 Microsoft Instructions: Manually Configure IPv4 Settings Scroll to the bottom and expand the section titled “To specify IPv4 settings manually.”

Then perform the following steps:

1. Set IP address to: 192.168.208.10

2. Set Subnet mask to: 255.255.255.0

3. Save the settings and close the window.

4. Connect the Mach J20 port to the dedicated network port on the control computer.

The M31 IP address (192.168.208.35) and the computer adapter IP (192.168.208.10) are pre-configured and should never be changed.

Verify MachPro Compatibility with the M31 Controller

For the M31 to function correctly with MachPro, the M31 must have the latest firmware and FPGA version. 

Verify Installed Versions

To check, follow these steps below: 

1. Open VSI Device Manager located at:
   "C:\Program Files (x86)\Vital System Inc\VSI Device Manager\"

2. Click Scan Network.

3. Compare the Firmware and FPGA versions shown with the files in
   C:\Mach\MotionControllers\M31.

If they match, the system is ready. You may close all windows and continue.

Note: If you cannot find the M31 when you scan network, the M31 IP address may not yet be configured to the current default IP. On the bottom right side of the VSI Device Manager, type in 192.168.208.35 and press Set New IP Addr. Cycle power on the M31 and you should be able to see it in the VSI Device Manager. 

If they do not match, follow the next steps to update the M31.

Update Firmware and FPGA on the M31

1. After scanning the network, locate your M31 in the device list.
   Click it once — the row will turn blue.

2. Click Switch to Loader.
   The row will change to tan, indicating Loader mode.

Updating the FPGA:

1. Click FPGA Fast Prog.

2. When prompted, navigate to C:\Mach\MotionControllers\M31 and select the FPGA file.

3. Follow the prompts to complete the update.

4. Click Reboot Device and wait for the confirmation that the operation is complete.

Updating the Firmware:

1. Click Switch to Loader again.

2. Click Load File, and select the firmware (.FW) file from
   C:\Mach\MotionControllers\M31.

3. Click Program Flash to install it.

4. Click Reboot Device and wait for the confirmation that the operation is complete.

When both updates finish, click Scan Network again and verify that the Firmware and FPGA versions now match the MachPro package files.

MachPro Startup

On the desktop of your control, there is a MachPro shortcut for your machine type. Below is an example of the MachPro shortcut.

After double clicking on your MachPro shortcut, a window will come up asking to  Press Cycle Start to Enable Mach and Home All Axes  . By default on a new installation, MachPro will just home in place. Press [Cycle Start] and the control will enable and home all axes.

This prompt can be turned off in the MachPro settings if desired. 

The configuration menus are locked if the system is enabled, and all the menu options will be grayed out. You need to disable the system in order to make configuration changes.

2 Axis Setup

M31 Motion Controller

All of the drives and external I/O will be wired into the M31. The M31 motion controller uses either EtherCat or step and direction to control the axes.

The axis drives and motors need to be wired, configured, and calibrated for accurate motion in section 2. Once that is completed, machine zero, limits, homing, and fixtures can be configured in section 3.

Step and Direction Connection and Configuration

The M31 supports differential or single-ended outputs. For differential outputs there are two signals for step (step + and step -) and two signals for direction (direction + and direction -). For single-ended there is only one signal for both step and direction. 

Motors
Stepper Channels	6 Motors
Step and Direction Axis Control	5V Single Ended and Differential
Connection	Terminal Blocks
Max Pulse Speed	1.6 MHz

If using step and direction, wire up your drives to J13-J18.

EtherCat Connection and Configuration

The M31 uses a standard EtherCat physical connection plan. The computer connects via Ethernet to J20 on the M31 motion controller. J19 on the M31 is then used to connect to each of the EtherCat devices.

• Put servo & stepper drives first in the EtherCAT chain (closest to the controller).

• Put I/O devices and safety relays in the middle.

• Put VFDs last (at the end of the chain). VFDs make electrical noise — keeping them last lowers interference.

• Use shielded network cable for all EtherCAT devices.

• Cable length: keep each cable between 1 foot and 100 meters (about 0.3 m – 100 m).

• Good cable management: keep cables neat, do not bend them sharply, and separate network cables from high-power lines when possible.
  

Load the EtherCat configurations

Pull down Configure -> Plugins -> M31 and select the EtherCAT tab

After downloading the configuration you will need to close the open window and restart MachPro for all configurations to be loaded. 

If the list of online devices in right column does not populate with valid devices, please contact MachLabs support. 

Configure individual EtherCAT motors

After restarting MachPro pull down Configure -> Plugins -> M31 and select the Motor[0] tab

The example below shows Motor[0] configured as an EtherCAT drive and connected to a Leadshine drive [1]L7N(COE)

1. Select EtherCAT Drive as the Control Output Type
2. Select the first EtherCAT Drive for Motor[0]
3. Select ECAT Feedback as the Feedback Source
4. Select the type of Homing configuration you are using for this motor.
   

Notes:

• Each motor has a Control Output SubID, and Feedback Index. The default is to leave those fields set to 0 for all motors. 

  

• The maximum following error is usually set to one or two rotations of the motor shaft. You may need to adjust for your system. Following error occurs when an axis is physically blocked from moving, or when part of the axis mechanics are slipping and commanded motion does not result in feedback motion. 
• Under the homing section are the adjustments for gantry squaring, and for enabling Absolute Encoder. 
• All unused motor tabs need to be set to Undefined 

  

Enabling Axes

After the drives are connected to the M31, open up MachPro, and enable the axes as follows:

Note: This may already be setup depending on your system.

1. On the menu bar, click Configure->Control . Then select the Motors tab (pictured below).

Note, if menu options are greyed out (not active/selectable), disable the system to allow configuration changes

1. Enable all the motors that are to be controlled by setting the respective boxes in the right pane to checks. In the example below, motors 0, 1, and 2 are enabled.
2. If a motor moves the wrong direction, it can be reversed in the MachPro. Check the  Reverse? box if the motor direction needs to be reversed. The motor will now move the opposite direction than it did before. If the homing direction was already set, it will need to be reversed as well. (see the homing section ). NOTE: If you are needing to reverse direction on an axis with a slave motor, you may need to change the direction for both the master and slave axis.
3.  Press [ Apply  ] to save any changes.
4. Next, select the  Axis Mapping  tab as pictured below. Associate the enabled motors to the applicable axis. In this example, Motor0 is the X master, Motor1 is the Y master, and Motor2 is not mapped to an axis. In this EtherCat system the VFD and spindle are motor 2, but will not be used for axis movement. No slave axes are configured on this system. 
5. If you have an axis with two motors - such as a gantry - one motor will be the master and the second will be the slave. In the slave column, select the motor that will be running in slave mode. In this example X axis has Motor0 as the master and Motor2 as the slave. 

   

6. Press [  Apply ] and [ OK ] to save and close.
7. Carefully test jogging. If you have a gantry with two motors, you may need to reverse one motor for correct motion. See step 2 above.

The system should now be able to jog, however,....

WARNING
 The machine can be crashed very easily at this point. The axes need to be calibrated and the limits set up now.

EtherCAT Drive Configuration

Before calibrating EtherCAT servos, you must know your motor resolution and cap it to 17 bits or 131072 per motor revolution. 

17 Bit Resolution

Motion based on 17 bit encoders is accurate enough for the majority of CNC systems, and it also allows you to select from a range of servo drives and motors. However, the drives will need to be configured to provide 17 bit encoder output even if they support a higher encoder count. This is a configuration change that is often made on servo drives, and it may be listed as Drive Ratio, User Parameter, Encoder Output Resolution, or Edge/Pitch. 

Yaskawa Sigma5 and Sigma7 drives use parameter PnB02 set to 8 to change their output to 17 bit. 

Each drive manufacturer has its own way to adjust the number of pulses that it will report for each rotation of the motor shaft.  You need to ensure that you can configure any drives you plan to use with the M31 for 17 bit output. 

Count	Bits	Conversion	Result
less than 131,072 (stepper drives)	less than 17	none	use the maximum resolution of the drive
131,072	2^17	none needed	131,072
1,048,576	2^20	8	131,072
8,388,608	2^23	64	131,072
16,777,216	2^24	128	131,072

Example of how the math works: The last row is a 24 bit drive.

2^24 = 16,777,216 pulses for each rotation of the motor shaft. Try dividing that by these numbers: 8, 16, 32, 64, 128

In this case 16,777,216 / 128 = 131,072 which is the number of pulses we are looking for. So, if you have a 24 bit drive, you need the drive parameter where you can plug in 128, and have the drive send 131,072 pulses per rotation to the M31.

Checking Resolution

How many bits is your drive sending to the M31? This process is easiest if the motor is not mounted on the machine.

1. Power up the system and MachPro, but leave MachPro disabled
2. Pull down Diagnostic | M31
3. Determine which axis you are checking and clear its position data. In the example above, Axis 0 has been selected. When the Clear Position button is pressed, the feedback value will be zeroed.
4. Now rotate the motor shaft one full rotation and note the feedback value. If it is a stepper motor, you may see approximately 10,000. If it is a servo motor you should see a number close to one of the numbers in the first column of the table above. 
5. If it is more than 131,072, your goal is to reconfigure the drive so that 1 rotation of the motor shaft produces approximately 131,072 pulses. 

Axis Calibration

Before calibrating the axes, set the backlash units to 0 for each axis. See the Backlash Repair and Compensation section below for details.

Go to  Configure-> Plugins -> Machine Calibration.

Select the type of configuration you would like to perform from the window:

• Manual - Calculate the axes by comparing distance traveled vs. distance commanded. See Manual Calibration below for instructions.
• Automatic - Calibrate axes using the specifications of your system. Continue for instructions.

Automatic Units Calibration 

Automatic calibration requires you to provide all of the details of your motor and axis hardware. If you are unable to find this information, proceed to the Manual Calibration section. 

1. Select the Drive that most closely matches yours. If there is not an exact match, select based on the number of encoder resolution bits. 
2. Select the max motor RPM
3. Enter 131,072 for the Encoder Resolution. If you have a stepper drive, or the drive is less than 17 bit, then enter the actual resolution per rotation for your motor. To verify the actual encoder resolution of your drive, please use the steps above in Checking Resolution. 
4. Enter 1 for the drive ratio. 
5. If this axis uses a pulley, select that box and enter the number of teeth from the load side and the motor side.
6. If there is a gearbox, select that box and enter the ratio.
7. This axis will have either a ballscrew or rack and pinion system. Select the type it has and complete the open fields.
8. Select the axis to calibrate.
9. Leave Angle at 0 degrees
10. Press the [Calculate] button.
11. Evaluate the current steps value against the proposed values. You may change values and re-calculate.
12. When you are ready to Accept the new steps per value, enter in the maximum Acceleration and Velocity values that you want for this axis. 

Repeat for each axis.

Press [OK] and restart MachPro to save the calibration settings.

This is an example of a simple X axis that has been calculated and is ready to be accepted. You may need to change the Acceleration and Velocity values to be appropriate for your machine. 

Verify that each axis is moving the distance that you command. 

Manual Calibration

This tool will enable you to calibrate your axes based on measuring actual distances moved and updating the MachPro parameters. Use the longest distance that you can accurately measure to calibrate each axis. 

You will be commanding motion on each axis. Carefully jog each axis to the middle of travel before starting calibration.

1. Select the axis to calibrate.
2. Select either Jog Distance or Commanded Distance. Jogging allows you to directly control the speed and distance the axis moves.

Manual Calibration Using Jogged Distance	Manual Calibration Using Commanded Distance
Press [  Enable  ] and then [  Record Jog  ] Jog the longest distance you can accurately measure Press [  Record Jog  ] again to stop the recording Measure the distance jogged and enter it into the actual travel field. Press [ Submit ] to calculate the steps per unit Press [ Accept ] to update the axis calibration. To verify, use the Commanded Distance function	Enter the distance and feedrate you want to use. Press [  Enable  ] and then [  Move  ]. Be prepared to press the E-Stop button if the axis moves too close to a hard stop.  Measure the distance moved and enter it into the actual travel field. Press [ Submit ] to calculate the steps per unit If the distances commanded and moved are the same, it will not change the steps per unit and you can press [ OK ] to close the window. If commanded and actual are different, press [ Accept ] to update the axis calibration. To verify, repeat the Commanded Distance function.
Pressing [ Accept ] at this point will update the steps per unit on this axis	Pressing [ Accept ] at this point will update the steps per unit on this axis

Axis calibration is a core function of a CNC control. Ensure that it now meets your accuracy requirements before moving on in the configuration. All of the following configuration steps depend on calibration, and if you later change the calibration, you will need to reconfigure many of the items below. 

Configure Velocity and Acceleration

If you want to adjust your velocity, select Configure on the top menu bar, then Control . Select the Motors tab as shown below. 

In the right pane, click on the motor you want to set up.

Click the word to highlight and select the axis. The checkbox is for enabling/disabling the motor

The selected motor’s parameters will be loaded and the velocity or acceleration settings can be adjusted.

• The max velocity is limited by several factors, including the motor. If you want an axis rapid speed to be limited or lowered, adjust the velocity for that motor to the max speed you want the rapid to be. The rigidity of the machine hardware will limit practical maximum velocity of an axis. The cut quality and accuracy will degrade as it reaches that point. 
• For stepper motors, max acceleration is typically 15-20 if in standard units. For servo motors, start with value of 30-40. This parameter also sets the deceleration rate, which interacts with a regeneration resistor - if one is installed on this axis. 

Press [ Apply ] before clicking on another motor or closing out the Mach Configuration window. NOTE: If you change the counts per unit, the velocity and acceleration values will adjust accordingly. If you do not want them to change, type in the current values shown. Verify by clicking another motor and then coming back to the adjusted motor.

WARNING
No limits have been set up. DEATH, INJURY or serious PROPERTY DAMAGE can occur if the system is not operated carefully. Limits and homing setup  will be completed in section 3

Backlash Repair and Compensation

Backlash is caused by the gaps between moving parts such as gears and ballscrews. It is the amount of movement one component can make in one direction without causing motion in the next connected part. Most mechanical systems have some backlash - even when new. If the mechanics are too tight, binding and excessive wear will result. As the gears and ballscrews wear, the backlash will increase, and accuracy will decrease. Ongoing testing and maintenance of your mechanical system is required to minimize backlash.

The M31 provides software backlash compensation as a short-term solution for small, stable amounts of backlash. To calculate the backlash of an axis use How To Test For Backlash 

Backlash Value – (Enter in Configure | Plugins -> M31). This field sets the backlash amount in inches or millimeters, depending on the setup units. For best performance, backlash should be less than .0015 inches. Start by entering half of the backlash value, test and adjust. 

Backlash Speed % – (Enter in Configure | Plugins -> M31) This is a factor of the axis acceleration value. The M31 takes the max acceleration of the motor and multiplies it by this percentage. Valid values are 10-400 (0.1 to 4 times max acceleration). A common value is 20%.

Do not leave the backlash speed  value at zero if you enter a backlash value. The M31 will not function. 

All of the axes are now calibrated, but MachPro does not know where the limits of travel are on each axis. That will be configured next. Until that setup is completed, be very careful if you are moving axes.

3 Inputs and Homing Setup

You will first need to wire the inputs and outputs to the M31. Then you will map the appropriate software signals to those hardware connections. 

Inputs	16 (PNP Sourcing)
Voltage	16-24VDC
Input Current Range	3 - 6mA
Isolated	Yes

Wiring Inputs

The M31 motion controller has 16 PNP inputs that can be used for the limit and home switches, probes, and other sensors. 

Note: For the highest level of safety,  wire the limit switches Normally Closed. If a limit is tripped, or a wire or limit is damaged, the system will stop motion.

To wire 24V limit switches, follow the steps outlined below. 

1. 1. Select, or install, two limit switches at the end of each axis' hard limits. 
   2. Wire the two switches in series, normally closed. If either limit is tripped, the circuit will open and motion will stop.
      1. I/O ports are limited, and wiring the limits for a given axis in series conserves those limited ports while maintaining function.

      2. Note that safety circuits often require each limit to have its own input. 

   3. Wire one side of the first switch to +24V  from the M31 motion controller.
   4. Wire the other side of the limit switch into an input on the M31. Label the wires and document the I/O.

Wire a home switch on each axis to a separate input. 

Tip for success: Once you understand how to wire and map inputs and outputs, complete the charts in the appendix at the end of this document.

Mapping Signals

1. At the top of the screen, open Configure → Control.

2. Click the Input Signals tab.

3. Scroll down the list until you see each motor section: Home, ++, and --.

4. For each signal mapping (Home, ++, --) do these steps:

   • Enable mapping: Click the red [ X ] next to the signal. It will turn into a green [ ✓ ]. That turns the mapping on.

   • Device: Choose M31 from the Device list.

   • Input Name: Pick the input you wired to the M31 (for example 1DI.01.08 or 1DI.01.09).

   • Active Low:

     • If your limit switches are normally closed, click the red [ X ] to change it to a green [ ✓ ].

     • This makes the input active when the voltage goes low. (Wiring normally closed is the safest method.)

   • Description: Type the name for this axis limit (the name operators and designers use).

5. When you finish all limits and home switches for a motor, click Apply, then click OK.

Short example

• Motor 0: Home, ++, and -- are enabled (green check).

• All limits are wired normally closed.

• We use M31 1DI.01.09 for both ++ and --.

• We use M31 1DI.01.08 for the Home switch. Using a separate input for Home is more reliable.

Manually trigger each limit switch and make sure they disable Mach before continuing. This verifies both the wiring and signal mapping.

Homing Setup

• Danger: If limit switches are wrong or an axis moves the wrong way, the machine can crash.

• Do this first: Keep your hand on the Emergency Stop button the first time you run homing.

• Open the settings: From the menu bar click Configure → Control. Then click the Homing/SoftLimits tab.

 

• Home Dir: Pick the direction the axis will move to find home — positive or negative.

• Home Order: Set the order of homing using numbers (1 = first, 2 = second, etc.).

  • Tip: Z is often set to 1 so it moves up first and stays out of the way.

• Home Speed%: Set how fast the axis homes by choosing a percent.

  • 20% is the usual maximum for best results.

  • Slower speeds help stop over-travel.

  • You can jog (move) the axis quickly close to the home position before homing to save time.

• Home In Place: Set this based on your hardware in the M31 config:

  • If you use home switches wired through M31 → make sure Home In Place shows a red X.

  • If you use absolute encoders in M31 → make sure Home In Place shows a green ✓.

• Save: Press OK to save your changes.

• Test: Home each axis one by one to check the settings. Then press Home All to verify everything works.
  

Homing Slave Axis

There are 2 configuration options:

1. Homing with the home switch only on the Master

Open Configure → Control → Axis Mapping. Unmap the slave motor from the Master column Find the motor listed under the Master column that will function as the slave. Remove or clear that motor so it is no longer mapped in the Master column. Set the slave motor Under Slave 1, pick the motor you want to be the slave (use the drop-down). Save your changes (press Apply)
Open Configure → Control → Input Signals. Find the Home signal row for the slave motor. Turn on that mapping (click the red [ X ] so it becomes a green [ ✓ ]). Set the Input Name to 1DI.01.08 (the same input the master uses). If your switches are normally closed, set Active Low to a green [ ✓ ] so the input triggers when voltage goes low. In Description write a clear name (for example: X Slave HOME uses Master's home sensor (1DI.01.08). Save your changes (press Apply)
Open Configure → Plugins → M31. The configuration for the master and slave motors are the same. For the master motor: Open the master motor tab. Choose one option: Home Sensor or Sensor + Index. Home Sensor = use the home switch. Sensor + Index = use the home switch plus an encoder index pulse. Uncheck Independent Master-Slave Home so the box is empty. For the slave motor:  Follow the same steps as for the Master motor. Save your changes (press Apply) and OK to close.

2. Homing with both Master and Slave having their own home sensors

Open Configure → Control → Axis Mapping. Unmap the slave motor from the Master column Find the motor listed under the Master column that will function as the slave. Remove or clear that motor so it is no longer mapped in the Master column. Set the slave motor Under Slave 1, pick the motor you want to be the slave (use the drop-down). Save your changes (press Apply)
Open Configure → Control → Input Signals. Find the Home signal row for the slave motor. Turn on that mapping (click the red [ X ] so it becomes a green [ ✓ ]). Make sure that each axis is mapped to its own home sensor input  If your switches are normally closed, set Active Low to a green [ ✓ ] so the input triggers when voltage goes low. In Description write a clear name (for example: X Slave HOME  (1DI.01.09). Save your changes (press Apply)
Open Configure → Plugins → M31. The configuration for the master and slave motors are the same. For the master motor: Open the master motor tab. Choose one option: Home Sensor or Sensor + Index. Home Sensor = use the home switch. Sensor + Index = use the home switch plus an encoder index pulse. Check Independent Master-Slave Home so the box is empty. For the slave motor:  Follow the same steps as for the Master motor. Save your changes (press Apply) and OK to close.

Set Slave Misalignment value if needed to "square" the gantry

https://support.machmotion.com/books/knowledge-base/page/aligning-slave-axis-gantry---mach4

 Troubleshooting

• What it means: The home switch used for the master may actually be wired to the slave (they are swapped).

• What happens: When you touch off switches and home, one side keeps moving and drags the other side. This is a sign the switch assignments are swapped.

• How to check:

  1. Touch each home switch by hand (one side at a time).

  2. Home the machine and watch each side while you touch the switches.

  3. If one side still travels and pulls the other side, the switch mapping is likely wrong.

• What to check in software: Look at Input Signals and Axis Mapping to make sure each switch is assigned to the correct axis.

• Safety: Keep your hand on E-Stop the first time you test after changes.

Soft Limits Setup

With machine homed correctly and soft limits set, the machine will not hit a physical limit switch. If at any time a command is made for the machine to move outside of the soft limits (while they are enabled), an error will appear in the status line and motion will stop. To set up the soft limits, follow the procedure outlined below.

1. Home the machine.
2. Select to view Machine Coordinates on the Locked screen view so that the DRO’s are orange.

   • 
     

3. Jog the machine to the maximum safe distance from the homing switches.
   • Note: Make sure to stay inside the physical limit switches. If the machine is jogged outside of the limit switches, it completely defeats the purpose of soft limits.
4. Record the machine coordinates at the end of the travel for each axis.
5. Jog the machine to the maximum safe distance beyond the homing switches, and record the machine coordinates for each axis.
6. Open the menu bar and click Configure->Control and select the Homing/SoftLimits tab as previously shown.
7. Enable soft limits on each desired axis by setting the Soft Enable column to a green check mark, and enter in the recorded values.
   • For each axis, enter the largest, most positive value in the Soft Max field, and the smallest, most negative value in the Soft Min field. 
8. Press [ OK ] to save changes. Test the soft limits by jogging the axes to maximum amounts in all directions.

Note: When loading a G-code file, the tool path display will show the soft limits as dashed lines. If any part of the tool path renders outside the soft limits, check your file.

4 Output Setup

Wiring Outputs

The M31 has 8 logic outputs that can be used for any low current application. 

Digital Outputs	8 (PNP Sourcing)
Voltage	16 - 24VDC
Max Current	250mA
Pulse Wave Modulation (PWM)	Not available on this release

Mapping Signals to Outputs

To configure an output, follow the procedure below.

1. On the menu bar click on Config->Control .
2. Select the Output Signals
3. Scroll down to the desired output (There are 64 output signals available).
4. Enable the output by setting the Mapping Enabled box to a green check.
5. Set the Device to M31 and the Output Name to (1DO.HwEN) This example maps the Hardware Enable.
6. Set the Active Low column to a green check for a normally closed signal (Active High) or red x for normally open (Active High).
7. Press [ Apply ] and [  OK ] to save changes.

Using Outputs

Outputs 0-5 can be controlled with M-Codes. One M-Code turns an output on, and the other M-Code turns the output off. Use the table below for a reference.

Custom M-Codes	Functions	Default Output
M200	Output 0 on	DO-2
M201	Output 0 off
M202	Output 1 on	DO-3
M203	Output 1 off
M204	Output 2 on	DO-4
M205	Output 2 off
M206	Output 3 on	DO-5
M207	Output 3 off
M208	Output 4 on	DO-6
M209	Output 4 off
M210	Output 5 on	DO-7
M211	Output 5 off

Mist and Flood Control

Mist is preconfigured in the MachPro software to be wired into Y0 and flood into Y1 output terminals.

Feature	ON M-Code	OFF M-Code	Preconfigured Output
Mist	M7	M9	Mist On – 1DO.01.07
Flood	M8		Coolant On – 1DO.01.06

5 Spindle Setup

Configure the VFD for the spindle motor

A VFD (Variable Frequency Drive) controls the speed of the spindle motor.

Set the VFD to match the motor’s electrical ratings:

• Rated voltage

• Rated current

• Rated speed (RPM range)

You must use the values from:

• The VFD manual

• The spindle motor manual

Do not guess these values.

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Spindle control options on the M31

The M31 controller can send the following signals to the VFD:

• Forward rotation signal

• Reverse rotation signal

• 0–10 V analog speed signal

If your VFD supports EtherCAT (Ethernet for Control Automation Technology):

• The M31 can control the VFD over EtherCAT.

• EtherCAT gives more control and access to advanced VFD functions.

Check your VFD manual to confirm EtherCAT support.

Using 0-10VDC to control the speed, and sinking outputs to control the rotation direction of the spindle

M31 Spindle features
Opto-Isolator Outputs	Forward and Reverse Open Drain / Open Collector outputs
Analog Speed Signal	0-10VDC
Encoder Feedback	Yes

M31 to VFD Direction Control – Field Wiring Guide

This section explains how to wire the M31 motion controller to a  VFD (Variable Frequency Drive) for Forward and Reverse control.

The language here uses standard sinking and sourcing terms used by field technicians.

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Key facts about the M31 outputs

• The M31 always uses sinking outputs.

• The Forward and Reverse outputs are optocoupled.

• Each output has an NPN sinking optocoupler to 0 V COM.

• When an output turns ON, it connects the VFD input to 0 V COM and sinks current.

• When an output turns OFF, the circuit is open and no current flows.

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Sinking vs sourcing – basic idea

• A sourcing device provides +24 VDC to the circuit.

• A sinking device connects the circuit to 0 V COM to let current flow.

• The M31 is a sinking device.

• The VFD digital inputs usually act as sourcing inputs when configured for sinking-mode wiring.

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What the VFD actually senses

• The VFD digital inputs sense current, not the 24 VDC level.

• The 24 VDC from the VFD is only a power source for the input circuit.

• The VFD decides ON or OFF by checking whether current flows into the digital input.

• If current flows, the input is active (Forward or Reverse commanded).

• If no current flows, the input is inactive (no command).

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How VFD digital inputs should be configured

Most VFDs allow different wiring modes for digital inputs.

For use with the M31:

• Configure the VFD digital inputs for sinking-type wiring.

• In manuals, look for terms like:

  • “Sink input”

  • “NPN input”

  • “Sinking (NPN) logic”

  • “0 V common for digital inputs”

  • “Digital inputs referenced to 0 V”

Avoid modes described as:

• “Source input”

• “PNP input”

• “24 V common for digital inputs” (where inputs switch to +24 V)

These modes are intended for sourcing outputs, not the M31.

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Role of the VFD’s 24 VDC control supply

• The VFD normally provides a 24 VDC control supply terminal.

• The VFD routes this 24 VDC to each digital input circuit.

• The 24 VDC exists only to allow current to flow through the input and the M31 output.

• The VFD’s decision is based on current presence, not on “seeing 24 VDC”.

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Forward and Reverse OFF (no command)

When both M31 Forward and M31 Reverse outputs are OFF:

1. Both optocoupled outputs are open circuits.

2. No current flows from the VFD’s 24 VDC supply through the Forward input.

3. No current flows through the Reverse input.

4. The VFD reads:

   • Forward input = OFF

   • Reverse input = OFF

5. The VFD sees no direction command.

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Forward ON – sinking current

When the M31 Forward output turns ON:

1. The VFD supplies 24 VDC to the Forward digital input circuit.

2. The VFD Forward digital input connects to the M31’s Forward Collector (FC).

3. The M31 closes the path between collector and emitter in the Forward output.

4. The emitter connects to 0 V COM.

5. Current flows:
   VFD 24 VDC → M31 Forward Collector (FC)→ M31 Forward emitter (FE) → 0 V COM

6. The M31 is sinking this current.

7. The VFD senses this current flow and interprets it as Forward = ON.

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Reverse ON – sinking current

When the M31 Reverse output turns ON:

1. The VFD supplies 24 VDC to the Reverse digital input circuit.

2. The VFD Reverse digital input connects to the M31’s Reverse  collector (RC).

3. The M31 closes the path between collector and emitter in the Reverse output.

4. The emitter connects to 0 V COM.

5. Current flows:
   VFD 24 VDC → M31 Reverse Collecter (RC)→ M31 Reverse emitter (RE) → 0 V COM

6. The M31 is sinking this current.

7. The VFD senses this current flow and interprets it as Reverse = ON.

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Wiring checklist for field technicians

When wiring a VFD to the M31:

1. Find in the VFD manual:

   • 24 VDC control supply terminal.

   • 0 V COM (or “DC-”, “CM”, “COM”) terminal.

   • Digital input terminals for Forward / Run and Reverse.

   • Digital input mode settings related to sink / source / NPN / PNP.

2. Configure the VFD digital inputs for:

   • Sink / NPN / sinking logic mode.

   • Inputs referenced to 0 V COM.

3. Wire the control supply and commons:

   • Connect VFD 0 V COM to M31 FE and RE.

   • Use the VFD’s 24 VDC as the field control supply for its inputs.

4. Wire the direction signals:

   • Connect the VFD Forward input to the M31 Forward collector (FC) terminal.

   • Connect the VFD Reverse input to the M31 Reverse collector (RC) terminal.

5. Verify operation:

   • Command Forward from the M31 and confirm the VFD sees Forward ON.

   • Command Reverse from the M31 and confirm the VFD sees Reverse ON.

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Summary

• The M31 always uses sinking outputs for Forward and Reverse.

• The VFD senses current, not 24 VDC level.

• Set VFD digital inputs to sink / NPN / sinking logic mode.

• The VFD sources 24 VDC, and the M31 sinks current to 0 V COM to signal direction.

For 0-10VDC speed control, look for Analog Inputs (AI) and 0VDC connections on the VFD. 

Analog Inputs: AI1, V1, AVI

0 volt: AC, 0V, ACM, GND

For direction control look for, or configure the Forward and Reverse digital control inputs on the VFD. This will also need a 0VDC connection.

Digital Inputs: S1, FWD, S2, REV,

0 volt: SN, SC, DCM

This is an example connecting the M31 to a Yaskawa GA500 VFD. Please refer to the documentation for your VFD.

M31 Motion Control	Yaskawa GA500 VFD
0-10VDC speed control	A1
0VDC	AC
Forward Collector (sinking)	S1 (forward by default)
Reverse Collector (sinking)	S2 (reverse by default)
Forward Emitter	SC (common)
Reverse Emitter	SC (common)

Here is a diagram showing the electronic circuit of the M31 on the Emitter and Collector signals:

Analog Spindle Voltage Adjustment

On the Systems  tab of the M31 plugin, the spindle voltage can be adjusted by changing the percentage (10-200%). Most systems will not require this value to be changed. However, if the voltage is not close enough, the percentage adjustment can be calculated with the following formula:

Analog Spindle Scale % = Commanded Voltage/Actual Voltage * 100

Encoder Feedback

Quadrature Encoder Channel	1
Connection	Terminal Blocks, 5V Differential
Max Frequency	1.6 MHz

Please refer to the documentation for your VFD and spindle motor for spindle encoder connections. 

EtherCat M31 Configuration

To access this configuration pull down Configuration | Plugins -> M31.

The feedback index will be the same as the motor number - in this case 3.

Set the Max Following Error very high as this is not meaningful for a spindle

Turning on the Spindle

In addition to the screen controls the spindle can also be controlled using M-codes. Use the table below as a reference.

M-Code	Function
M3	Clockwise
M4	Counter/Clockwise
M5	Stop

Spindle Calibration  

These instructions apply to all VFDs where the spindle is controlled through the MachPro Control Spindle tab

Why calibrate your spindle?

Does your CNC control need it? Mills and Lathes need to be calibrated while routers typically do not. The spindle speed needs to be accurate enough to meet your tooling specifications. 

• The rated speeds and feeds for your tools and materials should perform as expected.
• You should have comparable performance across all your machines when running the same spindle speed. 
• Accurate spindle calibration enables you to make cleaner and more accurate cuts – improving the quality of your final product.
• Scheduled preventative maintenance should include verification of the accuracy of the system, including the spindle speeds. 

This documentation focuses on knee mills as a common example and is adaptable to other machines. 

Prerequisites

• Your spindle needs to be configured according to your motion controller's capabilities for spindles. 
• The axes need to be calibrated
• Machine zero and soft limits need to configured
• The I/O, particularly limits, need to be connected and working

Definitions

Machines often have both gears and speed controls.

The control needs to know which physical gear is engaged to control the spindle motor for the correct speed. If you use multiple gears on your machine, there will be gear change buttons on the screen, and you can also

The speed control is a set of variable diameter pulleys that provide a variable speed within each gear. We often set this to the maximum RPM. Then we use the VFD to provide the full speed range within each gear. 

Set MaxRPM values for each gear

If you do not have a tachometer

Pull down Configure | Control | Spindle tab

If your machine only has one range (no pulleys or gears), then enter the minimum and maximum RPM for the spindle in the Range 1 row. 

If you have multiple gears, enter the rated maximum RPM for each gear into the MaxRPM column for each gear.

If you have a tachometer

Use the steps below to set the MaxRPM:

1. Set the spindle override knob on the operator control panel to 100%
2. Temporarily set all MaxRPM values to twice the labeled RPM on the speed control. This is not to destroy your machine. For calibration purposes this forces the VFD to the maximum hertz output - therefore the maximum tool RPM. We use that to calibrate accurate tool RPM for normal production.
   
3. Verify that the VFD is sending the maximum Hz to the spindle (see next section)
4. Run your machine in each gear range with the temporary MaxRPM values you used above. Verify that the VFD is putting out maximum Hz. Record the actual MaxRPM values from the tachometer for each gear range.
5. Enter the actual MaxRPM values that the tachometer reported in the spindle tab. 

If it is not safe to run this spindle at its maximum RPM, please contact MachLabs for assistance with calibration.

Verify that the VFD is sending maximum speed commands to the spindle

You need to know that the VFD is telling the spindle motor to run at full speed. Assuming the motor is configured to run at 60 Hz, then if the VFD is sending 60 Hz, the motor is running at full speed. You just entered the MaxRPM values into the spindle config. Set your machine for one of the gears and run the spindle at the MaxRPM. You can check the VFD output two ways, and both are equally accurate:

With the enclosure door open, check the LED on the VFD. This VFD is running at P44.59% of 60 Hz = 26.754 Hz. The "P" prefix on the number indicates the number is a percentage. Use the up or down buttons to cycle through the display. A V1000 will show the frequency with an "F" prefix. A GA500 will show the frequency with a "-" prefix.	Open a web browser and enter this IP address in the search bar 192.168.208.90. It will open a welcome page for the VFD with two buttons at the bottom. Click the Monitor button and look for the Output Frequency line. This is the same machine running at the same time, and it also reports 44.59% = 26.754 Hz.

Adjust feedback ratios for TSpeed

The formula is MaxRPM  / Maximum Motor RPM = feedback ratio

Pull down Configure | Control | Spindle tab

Check the ID plate on the spindle motor for RPM values. In this image we are running at 60 hertz; so we use the second value: 1735

MaxRPM from tachometer  / Maximum Motor RPM = feedback ratio

4485 / 1735 = 2.5850144092219020172910662824207

You can paste the the full value into the spindle FeedBack Ratio field for this range, or just 2.58501

Note: the feedback ratio only adjusts the value in the TSpeed field. It does not have any effect on the actual RPM of the spindle. If the spindle speed reported by a tach does not match commanded speed, then go here: Set MaxRPM values for each gear

Operating the spindle

Use M-Codes to operate your spindle during production: M3, M4, and M5 (relevant portion of the G-Code and M-Code Reference)

You can manually control the spindle with the buttons on your operator panel. 

Changing Gears

The gear ranges can be changed from the control by using M40-M45 in your G-Code file. These macros can be used to just change ranges or they can be used to automatically change gears on the machine if it has an automatic gear changer. To shift the machine range 0, run M40. M41 is range 1, M42 is range 2, and so on. You will be prompted to change the gear manually. M40 P# can also be used where # is the gear range to use.

Special situations

Overspeed a spindle motor

If you want to command your spindle motor or grinding wheel to go faster than the base frequency, command the spindle to go max RPM and use a tachometer to measure the speed. Then use the following formula to calculate your new Max Output Frequency (Hb105):

Desired Max RPM * Current Max Frequency / Current Max RPM = New Max Frequency 

For example, if your Current Max Frequency is 60 and you measure the spindle runs 1030 RPM but you actually want it to go 1515 RPM, calculate your new Max Frequency as follows: 

1515 * 60 / 1030=88 Hz. 

Make sure to recalibrate your RPM feedback and your spindle speed as shown below. 

Set a spindle to always run at maximum RPM

In some cases, a machine was originally configured to run the spindle motor at full speed, and the gears and speed controls are used to bring the RPM down to the required value. A motor running this way will always generate its maximum torque, which is very helpful when using large tools.

Pull down Configure | Control | Spindle tab

Set your MinRPM and MaxRPM for each gear to the same value.
Set your Max Spindle Motor RPM to the rated value listed on the spindle motor plate.

Leave the FeedBack Ratio values alone as they are no longer meaningful.

The spindle section of you screen can now be ignored. You will adjust your spindle speed entirely through the gears and speed control.

The rest of the spindle configuration above is not needed when it is configured to run maximum RPM.

Auxiliary Spindle MaxRPM

If your VFD is enabled as an Auxiliary spindle (under MachPro settings), set the Auxiliary Control Max RPM to the max RPM of the tool or table. Use this value both in the VFD configuration, and in the sub spindle configuration. Also see this section on sub spindle configuration

6 Advanced Options and Information

MachPro Settings

A number of advanced features can be configured in the Mach Settings such as periodic oiler control. Begin by going to  Configure->Control and got to the Settings tab. Settings contains custom options for the control, including dialogue options, lube system, tool measurement/offsets, and tool changer options.

Lube System Setup

The system may require an oiler. Enable the lube system, choose an action trigger, set the lube output, set the time run time of the oiler, and the time between cycles. In the example below the lube output will turn on at 5 minute intervals for 8 seconds when it is enabled. In this system it is not enabled.

Tool Setter Setup

Global Monitoring System

Global Monitoring is used to setup user alerts or messages as well as to control I/O functionality based on certain conditions. To access the Global Monitoring System, go to  Configure -> Plugins -> Global Monitoring System tab. The system allows the machine to watch for specified conditions, and take action when those conditions are met. For information on creating, editing, or deleting a message, visit our Global Monitoring System knowledge base online at: https://support.machmotion.com/books/knowledge-base/page/global-messaging .

7 Appendices

Signals and ports used

Signal	M31 Junction	Input Name	Use
	J1	1DI.01.00
	J1	1DI.01.01
	J1	1DI.01.02
	J1	1DI.01.03
	J1	1DI.01.04
	J1	1DI.01.05
	J1	1DI.01.06
	J1	1DI.01.07
	J3	1DI.01.08
	J3	1DI.01.09
	J3	1DI.01.10
	J3	1DI.01.11
	J3	1DI.01.12
	J3	1DI.01.13
	J3	1DI.01.14
	J3	1DI.01.15
	J3	1DI.01.16

Signal	M31 Junction	Output Name	Use
	J10	1DO.01.00
	J10	1DO.01.01
	J10	1DO.01.02
	J10	1DO.01.03
	J10	1DO.01.04
	J10	1DO.01.05
	J10	1DO.01.06
	J10	1DO.01.07

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