Micro Direct Drive Motor Servo Driver FAQ

A μDD Motor is an AC servo motor driven by a DC-powered servo driver.

Internally, it uses a three-phase permanent-magnet motor structure. It supports smooth position and speed control from very low speed to high speed, as well as precise current and torque control.

High-precision positioning is supported by the motor’s finely divided stator-slot design, integrated high-resolution encoder, and direct drive structure.

Because the load is driven without a gearbox or timing belt, transmission backlash and belt elasticity are eliminated.

Final machine accuracy also depends on the mounting structure, load rigidity, bearing condition, servo tuning, thermal conditions, and controller settings.

The gearless direct drive structure does not produce gear-meshing noise or timing-belt transmission noise.

This can reduce mechanical operating noise compared with a system using gears, belts, pulleys, and couplings.

Yes. μDD Motors use high-rigidity bearings, so the load can be mounted directly to the output shaft when the applied radial, axial, and moment loads remain within the allowable range.

Check the applicable product drawing and specification before designing the load connection.

Repeated reciprocating motion over an extremely small angle may shorten bearing service life because the same limited bearing area is continuously loaded.

When possible, periodically rotate the motor through a wider angle or a complete revolution so that the bearing load is distributed across a larger area.

Contact MTL with the operating angle, frequency, load, speed, and expected service life for a detailed review.

A μDD Motor can be installed vertically, but its high backdrivability means that it does not normally hold a vertical load when servo power is removed.

For vertical or safety-critical axes, consider a brake, counterbalance, reducer, mechanical stopper, or another suitable holding mechanism.

No. The internal step is created by the shaft machining process and is not a product defect.

Use an inserted shaft or component with dimensions that remain within the usable hollow-bore dimensions shown in the product drawing.

Both types are available.

A model number ending in “E” indicates an incremental encoder. A model number ending in “B” indicates an absolute encoder.

Face runout and radial shaft runout are generally approximately 20 to 30 μm for the referenced standard configuration.

Confirm the value for the exact model in the applicable drawing. Contact MTL regarding higher-precision machining requirements.

Yes. A positioning pin can be reviewed as a customization option.

Please provide the required pin position, diameter, length, tolerance, load, and mating-part drawing.

The available speed depends on the motor series, encoder resolution, driver, supply voltage, and controller input frequency.

For example, some MD-20 configurations can operate at approximately 4,000 rpm. Contact MTL with the exact motor model and operating conditions.

Gear-equipped configurations may be available for evaluation or purchase, depending on the model and application.

Please contact MTL to confirm the current lineup, reduction ratio, torque, backlash, dimensions, and loan-unit availability.

Available peak torque and continuous torque will be significantly reduced. Under the referenced conditions, the reduction may be approximately 70%.

Use the specified 48 V supply when the rated motor performance is required.

The referenced instantaneous peak current is approximately 7 A, and the rated current is approximately 3.2 Arms.

A power-supply capacity of at least 168 W should be considered. Additional capacity may be necessary depending on acceleration, load, regeneration, and duty cycle.

Typical measures include correct FG wiring, appropriate shield termination, separation of signal and power cables, and avoidance of ground loops.

Also confirm the power-supply grounding, signal common, cable routing, termination resistance, and noise sources in the surrounding equipment.

Refer to the applicable drawings, specifications, and support documents for model-specific requirements.

Select the power supply based on the motor rated current and supply voltage.

Provide additional capacity according to the peak current, load, acceleration, deceleration, operating cycle, and number of axes.

The available command methods depend on the driver model and may include pulse commands, analog current commands, USB communication, SPI communication, and EtherCAT.

Select the controller according to the required control mode, command cycle, communication interface, positioning method, and synchronization requirements.

The function of each CN1 pin is shown in the applicable product drawing and specification.

Please contact MTL with the exact driver model if you require the relevant technical document.

Yes. A-phase, B-phase, and Z-phase signals can be obtained from the applicable CN4 output.

Encoder position information can also be read through supported communication functions, depending on the driver model.

Absolute position information is output from CN4 pins 27 and 28 as an RS-422 differential signal.

ASCII or binary output formats can be used according to the driver configuration.

The referenced current consumption is approximately 150 to 250 mA while the servo is OFF.

When the servo is ON, add the motor drive current required by the actual load and motion profile.

The referenced current consumption for the MC-200-7220A CN4 interface power supply is approximately 50 to 100 mA.

Assign the emergency-stop or deceleration-stop function to a DIN input and send the applicable command from the upper-level controller.

The machine safety circuit must be designed according to the required safety category and applicable standards. A normal driver input should not be treated as a certified safety function unless explicitly specified.

Yes. The driver can output or report the encoder position while the motor is manually rotated with the servo OFF.

Prevent excessive temperature rise and provide adequate ventilation or forced cooling when necessary.

Installation with CN1 facing downward is recommended for the referenced configuration. Also maintain the specified mounting clearance and ambient-temperature limits.

Motor torque can be estimated by multiplying the effective motor current by the motor torque constant.

The effective current value can be obtained through USB communication or the applicable CN4 monitor output.

The Z-phase signal can be used as part of the homing sequence.

Assign the HOME function to the applicable DIN input and configure the homing direction, speed, sensor logic, and pulse command according to the system requirements.

The detailed electrical specifications are listed on page 16 of the referenced product specification.

The applicable pins use a 5 V CMOS interface. Confirm the exact model and document revision before wiring.

Viewed from the external equipment side, it is a sink input.

Use an input voltage within the specified VCC range of 5 to 24 V.

Yes. Position and speed commands can be sent through USB communication using the applicable driver commands.

Yes. The motor current can be obtained using the applicable $Ecur or $G command.

Set parameter No. 100 to “30” and parameter No. 101 to “1.”

Save the settings and restart the driver to apply the changes.

Use parameter No. 300 to select one of the following:

• PLS/DIR
• CW/CCW
• Two-phase 90-degree phase-difference input

The referenced maximum frequency is 2.5 MHz for single-phase pulse input.

Refer to the firmware update instructions and repeat the procedure using the specified USB connection, power sequence, file, and software version.

View the Firmware Update Manual

The encoder cable may be disconnected, incorrectly wired, or not securely connected.

Inspect the encoder wiring, connector, cable continuity, and motor-model settings.

The configured encoder resolution or motor model may not match the connected motor.

Check the motor model and encoder settings in MTLParam.

The load, acceleration, deceleration, or commanded motion may be excessive.

Review the load conditions, motion profile, gain settings, motor installation, mechanical interference, and alignment.

Check parameter No. 406, the position-control gains, command profile, load, available torque, and mechanical movement.

The power-supply capacity may be insufficient, or the input voltage may be dropping during acceleration.

Check the supply voltage at the driver terminals, power-supply capacity, cable size, wiring length, and connector condition.

The driver output current has exceeded the configured thermal limit.

Review the load, motion cycle, acceleration, deceleration, current settings, ambient temperature, mounting clearance, and cooling conditions.

The internal count value has exceeded the 32-bit range.

Reset the counter to restore operation, then review the operating range and counter-reset sequence.

Confirm that the installed MTLParam version supports your Windows environment.

Also check the USB driver, COM port number, baud rate, USB connection, cable length, and whether another application is using the same port.

Install the FTDI Virtual COM Port, VCP, driver that matches your operating system.

Contact MTL if you cannot access or install the required driver.

“K” represents 1,000.

For example, 108KE indicates an encoder resolution of 108,000 pulses before external multiplication.

No. Enter the encoder resolution before external x4 multiplication.

For example, enter 108,000 for a 108,000-pulse encoder.

A sampling time of approximately 50 to 100 ms is recommended for the referenced use.

Close unnecessary display items to reduce the processing load during waveform measurement.

Use the CN4 analog monitor to observe the effective current while adjusting the proportional and integral gains.

Gain adjustment should be performed carefully because unsuitable settings can produce vibration, noise, excessive current, or unstable operation.

Confirm that the command source is set to internal command and that the control mode is set to position control.

Also confirm that the MODEL settings match the connected motor and encoder.

Orders can generally be accepted from one unit.

Made-to-order products typically require approximately two months after order confirmation. Actual lead time depends on the model, quantity, customization, component availability, and production schedule.

Some models may be available from stock.

Submit the required model number, quantity, application, installation country, end user, and target schedule through the MTL contact form.

MTL will review the technical and commercial requirements and provide the appropriate quotation or regional sales route.

Contact MTL

Selected models may be available as loan units.

Some units may need to be prepared in advance. The standard loan period is generally up to three weeks.

Availability depends on the requested model and schedule.

Technical documents are available for applicable motor and driver models.

Submit the exact model number and required document through the contact form.

Request Technical Documents

MTL can review and issue applicable export-classification documentation for its products.

Preparation normally requires approximately one week, but the required period may vary. Submit the exact model, destination country, end user, and intended application in advance.

A Declaration of Conformity may be issued for applicable products and tested configurations.

Please provide the exact motor model, driver model, and required documentation so that MTL can confirm applicability.

Demonstrations can be arranged at the MTL showroom.

A portable demonstration unit may also be available for an on-site presentation, depending on the location, application, and schedule.

MTL does not normally provide overseas on-site service.

When product inspection is required, send the product to MTL for investigation and analysis.

Inform MTL in advance when the product will be exported or installed overseas.

Compatible combinations are available.

Refer to the applicable collaboration catalog and confirm the exact motor and amplifier models before selection.

Compatible combinations are available. However, the MD-20 Series is not supported in the referenced configuration.

No. An amplifier prepared or configured for the applicable μDD Motor combination is required.

The referenced collaboration configuration supports an SSCNET III-compatible amplifier, not the CC-Link IE-compatible configuration.

Yes. Dedicated conversion connector cables are available for applicable motor and amplifier combinations.

Yes. Contact MTL or the applicable Mitsubishi Electric sales representative or distributor.

MTL can provide the applicable motor parameter setting file.

Submit the exact motor model and amplifier model when requesting the file.

Purchase the μDD Motor through MTL or the applicable MTL sales channel.

Purchase the amplifier through the applicable Mitsubishi Electric sales channel.

Perform an initial diagnosis to determine whether the issue is related to the motor, cable, amplifier, settings, or upper-level controller.

Contact MTL for motor-related issues and the amplifier manufacturer or distributor for amplifier-related issues.

It may be possible, but the available torque, current, acceleration, and speed characteristics will change.

Contact MTL with the motor model, amplifier model, load, and motion profile before selection.

A general reference value is approximately 50 times the motor inertia.

Higher ratios may be possible depending on the mechanical structure, required response, operating profile, and servo tuning.

Compatible combinations are available.

Refer to the applicable collaboration catalog and confirm the exact motor and amplifier models.

Compatible combinations are available. However, the MD-13 and MD-20 Series are not supported in the referenced configuration.

Compatibility depends on the exact amplifier model and motor configuration.

Provide the amplifier model and required μDD Motor model for confirmation.

Yes. Dedicated conversion connector cables are available for applicable combinations.

Yes, for applicable configurations. An MFC-10P conversion board box is required for the referenced system.

An applicable A6BL configuration can be used for the referenced EtherCAT connection.

Confirm the exact motor, encoder, amplifier, firmware, and communication configuration before selection.

Contact MTL or the applicable amplifier distributor according to the required product and regional sales channel.

Perform an initial diagnosis to identify whether the issue is related to the motor or amplifier.

Contact MTL for motor-related issues and Panasonic or the applicable distributor for amplifier-related issues.

Yes. Submit the required specifications so that MTL can review feasibility, development cost, lead time, testing requirements, and specification control.

Typical customization examples include:

• Encoder resolution changes
• Internal thread machining in the hollow shaft
• Low-particle-generation specifications
• Enlarged hollow-shaft bore
• Cable-length changes
• Connector changes
• Flangeless motor housing
• Output-shaft modifications
• Pinion gear integration
• Positioning-pin addition
• Knurled shaft machining
• Aluminum anodizing

View Customization Examples

Please contact MTL to confirm the current availability of brake-equipped models and possible alternative holding mechanisms.

Depending on the application, an external brake, counterbalance, reducer, or mechanical lock may be recommended.

Master-slave control allows the motion of one axis to be reproduced by another axis.

It can be used for remote operation, synchronized movement, direct teaching, force-feedback systems, and teleoperation mechanisms.

Learn More About Master-Slave Control