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M31 Motion Control Setup Manual

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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.

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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



Motor Drives


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.

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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.

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Restart the MachPro software to ensure smooth operation.

If you have problems with the automated upgrades, you should use the manual upgrade process. MachPro Manual Upgrade of M31 Firmware and FPGA

Hardware Startup (J8)

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.

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Emergency Stop (E-stop Circuit J6)

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.

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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.

  • Pull down Configure -> Control and click the Input Signals tab
  • Scroll down the input signals to reach the E-Stop signal

  • 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.

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Hardware and drive enable overview (J12)

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.

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I/O Diagnostics

The M31 and MachPro have a rich set of diagnostics.

  • Each input and output on the M31 has an associated LED
  • The M31 Diagnostic screen shows the status of all I/O at the motion controller level (click Diagnostic -> M31)
  • The MachPro Input Signals screen shows the state of all enabled signals in the State column (click  Configure->Control, then click Input Signals)
  • The MachPro Machine I/O screen also shows the state of all mapped I/O (click the Service tab, then the Machine I/O tab)

While you are wiring and mapping I/O signals, confirm that each I/O port is changing correctly at the M31 - with its diagnostic LEDs, and in the MachPro software. 

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Input pin 1 is active - 1DI.01.01

The E-Stop is active - 1DI. ESTP

There is power to the board.

The blue CPU LED will blink when the CPU is active











 

Configure the Dedicated Network Interface (J20)

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.

If you need to reset the IP address on the M31:

  • Verify: The M31 has 24VDC power
  • Verify: The M31 and computer are connected with an ethernet connection
  • Open the VSI Device Manager software

You should see the VSI Device Manager icon on your windows desktop

 

OR,

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Click the Windows Start button and search for VSI

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The VSI Device Manager will appear as one of the windows below. 

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  1. Click Scan Network
  2. Click the device that the scan locates. It will show the current IP address on the line at the top as well as an editable field in the lower right corner.

    • You may not see an M31 in the VSI Device Manager. Still follow steps 3 through 6.

  3. Enter 192.168.208.35 
  4. Click Set New IP Addr
  5. Click Close
  6. Close MachPro, power cycle the enclosure, and restart MachPro. This ensures that all network and software changes are fully enabled. 

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.

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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.

cycle-start-prompt.jpg
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.

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2 Axis Setup

We recommend that you initially do a test setup with your motors.

  • This ensures that you have all the cables you need
  • You can verify that the motors all work
  • You can easily verify that your drives are set to 17 bit or less.

Set the motors on a stable work surface. Often the packing materials will work well as temporary pads. 

Connect all cables between each drive and motor. You may leave the motors setup like this until you calibrate the axes.system is ready for axis calibration.

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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.

The M31 will support both Step and Direction, and EtherCAT devices simultaneously. 

Step and Direction Connection and Configuration (J13 - J18)

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. 

Note: The M31 does not support powering and controlling motors directly. It is designed to supply control signals to a drive, which will power and control the motor.

Motor Drives


Stepper Channels

6 Motors

        Step and Direction Axis Control

5V Single Ended and Differential

                Connection

Terminal Blocks

                Max Pulse Speed

1.6 MHz

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

Connect to a single-ended drive input

Use this when

    • The controller has true differential (RS-422) step/dir outputs, and

    • The drive has single-ended step/dir inputs.

Connections

    • Connect S+ → drive STEP input.
      Drive label examples: “PUL”, “STEP”, “CP”.

    • Connect D+ → drive DIR input.
      Drive label examples: “DIR”, “CW/CCW”.

    • Connect controller 0 V → drive input common / signal ground.

      • Drive label examples: “PUL-”, “DIR-”, “COM”, “GND”, “SG”, “DCM”.

      • We recommend that you run a single 0V wire from the J11 block to your drives. This is a series (pass-through) connection.

      • You connect the 0 V output of the power supply to the first drive. Then you connect the 0 V terminal of that drive to the 0 V terminal of the next drive. Continue this pattern for all drives.

      • M31 J11 0 V → Drive 1 (0 V) → Drive 2 (0 V) → Drive 3 (0 V)

Do not connect

    • Leave S- and D- unconnected.

Why

On many controllers, S- and D- are the inverted, actively driven outputs of the differential pair. If you tie them to 0 V, you can short an output or distort the signal. This can cause missed steps or faults.

Connect to a differential (RS-422) drive input

Use this when

    • The controller has true differential (RS-422) step/dir outputs, and

    • The drive has differential step/dir inputs.

Connections (typical)

    1. Connect S+ → drive STEP+ input.
      Drive label examples: “PUL+”, “STEP+”, “CP+”.

    2. Connect S- → drive STEP- input.
      Drive label examples: “PUL-”, “STEP-”, “CP-”.

    3. Connect D+ → drive DIR+ input.
      Drive label examples: “DIR+”, “CW+”.

    4. Connect D- → drive DIR- input.
      Drive label examples: “DIR-”, “CW-”, “CCW-”.

0 V connection

    • In most differential interfaces, a separate 0 V wire is not required for the signal to work, because the receiver measures the voltage difference between “+” and “-”.

    • If the drive manual specifies a signal ground, shield drain, or COM connection for noise control, connect it as specified. If the drive manual does not require a 0V connection, then do not connect it. Do not use S- or D- as a ground.

Notes

    • Use twisted pairs: S+ with S-, and D+ with D-.

    • If you use cable shield, bond it per your grounding standard and the drive manual (usually at one end).

EtherCat Connection and Configuration (J19)

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.

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Load the EtherCat configurations

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

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You may need to refresh the network several times to retrieve all of the information. 

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If any of the devices report a status of Unsupported, please contact Mach support using the information at the end of this manual. 

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After downloading the configuration you will need to close the M31 Config window and restart MachPro for all configurations to be loaded. 

EtherCat Troubleshooting
  1. Close the MachPro software and then shutdown the computer
  2. Cycle the power on the whole machine
  3. Restart the computer and the MachPro software. Recheck to see if you are still having a problem.

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

EtherCAT Drive Configuration

Before calibrating EtherCAT servos, you must know your motor resolution and cap it to 17 bits or 131072 counts per motor revolution. This is the maximum number of counts per revolution that the M31 supports. 

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.

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  1. Power up the system and MachPro, but leave MachPro disabled, which will allow the motors to be rotated by hand
  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 by hand 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. 

When you have configured all of your drives to use 17 bit resolution, save and close all open windows. Close MachPro.

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.

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Notes:

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

    image.png

  • 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 

    image.png

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/select-able), 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. image.png
  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.  image.png
  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. 

    OjEimage.png

  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.

Testing Axis Motion

Once the M31 Motion Controller is correctly wired to the drives, and they are wired to the motors, you can test motion. The M31 plugin provides controls for making very small test movements on each axis individually. 

Ensure that each axis is able to safely move both directions without damaging the axis or machine. Note that the only limits it has are the hard stops on each axis. If you have the motors on a test bench, there is no risk. 

Pull down Configure -> Plugins -> M31 and select the first axis you want to test.

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The black window at the bottom will display the results of your test. Initially yours will be blank.

You will set movement values in the Test Motion section at the right of the window.

  • Postion: distance to move. Start with 0.1 or smaller
  • Accel: start with a low value - 10
  • Velocity : start with a low value - 10
  • Auto-Reverse: select this (lower portion of right column)
  • Click the Enable button at the bottom of this section

This axis is now ready to test motion

 

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  • When I click the Execute button, the axis should move. (The axes are not yet calibrated. So the distance just needs to be very small. 
  • When I click Execute again, it should move in the opposite direction. 

 

Note that the graph shows the commanded and actual position are tracking well, but the speed is not doing well. That is because we are running at very low movement values.

 

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  • I increased my position to 0.3", which is still a very safe movement.
  • I gradually increased my Accel to 20 and my Velocity to 200. These are reasonable values for this axis on this machine. 
  • Now my graph shows more realistic speed and position results. 

 

Note that I am still moving very small physical distances, and my only goal is to ensure that the motion controller, drive, and motor are working properly together.

Repeat these steps on each axis.

If you have been running your motors on a test bench, you now need to mount the motors on the machine in their running configuration.

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

 

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. 

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  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. 

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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

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  1. Press [  Enable  ] and then [  Record Jog  ]
  2. Jog the longest distance you can accurately measure
  3. Press [  Record Jog  ] again to stop the recording
  4. Measure the distance jogged and enter it into the actual travel field.
  5. Press [ Submit ] to calculate the steps per unit
  6. Press [ Accept ] to update the axis calibration.
  7. To verify, use the Commanded Distance function
  1. Enter the distance and feedrate you want to use.
  2. Press [  Enable  ] and then [  Move  ]. Be prepared to press the E-Stop button if the axis moves too close to a hard stop. 
  3. Measure the distance moved and enter it into the actual travel field.
  4. Press [ Submit ] to calculate the steps per unit
  5. 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.
  6. If commanded and actual are different, press [ Accept ] to update the axis calibration.
  7. To verify, repeat the Commanded Distance function.

Pressing [ Accept ] at this point will update the steps per unit on this axis

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Pressing [ Accept ] at this point will update the steps per unit on this axisimage.png

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. 

image.pngIn 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%.

image.png

Do not leave the backlash speed value at zero. The M31 will not function with a speed of zero. 

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 (J1 & J3)

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. 

image.png

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.

kR3image.png

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

    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.

bzRimage.png

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.

 homing-config.JPG

    • 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)

    image.png

    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.01.09 (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: (1DI.01.09 X2 HOME uses X1 home sensor ).

    • Save your changes (press Apply)

     

    image.png

     

    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.

    image.png

    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)

    image.png

    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: X2 HOME  (1DI.01.13).

    • Save your changes (press Apply)

     

    image.png

     

    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.

    image.png

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

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

    Close MachPro, power cycle the enclosure, and restart MachPro. This ensures that all M31 and software changes are fully enabled. 

     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 (J10)

    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

    image.png

    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.

    image.png

    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 (J5)

    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.

    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.

    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.

    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.

    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).

    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.

    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”.

    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.

    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.

    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.

    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.

    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.

    image.png

    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.

    image.png

    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:

    image.png

    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 (J4)

    dnQimage.png

    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.

    image.png

    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  

    {{@2049}}

    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.

    image.png

    Tool Setter Configuration

    {{@1995}}

    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

    8 Troubleshooting

    Step and Direction

    You are not seeing motion on one, or all axes

    1. Slow down your speed to see if it moves at slow speed. 
    2. Reduce your steps per unit and jog slowly.

    EtherCAT

    • The EtherCAT cables must be shielded
    • Very carefully check the In/Out cabling sequence through the entire EtherCAT chain. If one or more of the devices is backwards, the EtherCAT network will power up, but will not enable.
    • All of the drives need to be programmed, and all alarms cleared. With some drives, you can clear the alarm from the face of the drive, but not clear the alarm state internally. Close the MachPro software and power cycle the enclosure. Then restart the MachPro software. 
    • Drives connected to the M31 Motion Controller must be configured for 17 bit or less. If they are configured for more than 17 bit, the system may still have motion, but it will be very sluggish. 
    • If you see a Not Supported status next to a device in the EtherCAT tab of the M31 Config window, contact support. 

      image.png

    Network

    Are the M31 motion controller and computer connected and communicating?

    • Ensure that the Motion port on the computer is connected to the Mach J20 port on the M31.
    • From the MachPro software, pull down  Diagnostic -> M31 
    • The value in the GCode Message Cntr should be actively changing 

      image.png

    • If it is a static value or 0:
    • Close MachPro and power cycle your enclosure, then restart MachPro
    • Research and resolve all alerts and warnings that come up during that process.
    • Verify your network settings. If you need to make changes, close MachPro and power cycle the enclosure. 

    Explanation

    EtherCAT State Machine

    When enabling or booting up, an EtherCAT slave device moves through a specific sequence of four main communication states managed by the EtherCAT State Machine (ESM):
    1. Init (Initialization)
      • This is the initial state after power-on. No mailbox or process data communication is possible. The master initializes the slave's address and communication settings. The EtherCAT master is answering the question: "What kind of device are you?" for each device in the chain.
    2. Pre-Operational (Pre-Op)
      • Mailbox communication is enabled, allowing the master to configure SDOs (Service Data Objects), PDO (Process Data Object) mapping, and other parameters. Process data communication is not yet active. The EtherCAT master is answering the question: "How are you configured?" for each device in the chain.
    3. Safe-Operational (Safe-Op)
      • The master and slave check the configuration. Mailbox and process data communication are active, but the slave only sends input data; outputs are held in a safe state (e.g., switched off). If there are any device alarms, EtherCAT will not move past this state.
    4. Operational (Op)
      • The slave is fully functional. Both mailbox and process data communication are active, and the master sends output data, which the slave applies.

    {{@2016}}

     

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