1. Introduction
The Makerbase MKS SERVO42C PCBA is a high-performance closed-loop stepper motor driver designed to prevent step loss in 3D printers and CNC machines. It integrates advanced control algorithms and a 14-bit magnetic encoder to ensure precise positioning, high speed, and low noise operation. This manual provides detailed instructions for installation, operation, and maintenance of your MKS SERVO42C PCBA.
2. Key Features
- Easy installation and wiring.
- Position/speed/torque closed-loop control, enabling high-speed operation without losing steps.
- Field-Oriented Control (FOC) for low noise, low vibration, and reduced heat generation.
- Equipped with a 4 Half bridge driver and 8 MOSFETs for high operating efficiency.
- Features a 14-bit magnetic encoder for high angle resolution.
- Supports 1-256 subdivision, including odd subdivisions (e.g., 11).
- Compatible with motors having 0.9-degree or 1.8-degree step angles.
- Achieves a maximum speed of 1000 RPM.
- Includes a USART interface for connecting to a computer for parameter adjustment and query.
3. Package Contents
Verify that all items are present in your package:
| Item | Quantity |
|---|---|
| MKS SERVO42C PCBA (motor not included) | 1 |
| Adapter board (MKS APT) | 1 |
| 304 Hexagon socket screw (40mm) | 4 |
| ABS gasket (3mm) | 4 |
| 6*2.5 Radial Magnet | 1 |
| Allen wrench - M3 | 1 |
| 4pin Motor Cable (3cm) | 1 |
| 6pin Data Cable (60cm) | 1 |
4. Specifications
4.1. General Parameters
| Parameter | MKS SERVO42C |
|---|---|
| Frequency of Update | Position 10kHz, Velocity 10kHz, Torque 20kHz |
| PID Control Mode | Incremental PID |
| Driver | 4 Half bridge driver with 8 MOSFET |
| OLED Display | YES |
| Operating Voltage | 7-28V |
| Adjustable Current Range | 0-3000mA |
| USART Interface | YES |
| Field-Oriented Control | YES |
| Subdivision | 1-256 (set by key or serial port) |
| Angle Resolution | 0.08 degrees |
| Maximum Speed | 1000RPM |
| Motor Vibration | Low |
| Motor Noise | Low |
| Motor Temperature | Low |
4.2. MKS SERVO42C vs. MKS SERVO42C_OC Comparison
| Feature | MKS SERVO42C V1.0 (Green) | MKS SERVO42C_OC V1.0 (Blue) |
|---|---|---|
| Appearance |  |  |
| Signal Common | Positive, Negative, NC | Positive |
| Signal Voltage | 3.3~24V | - |
| Signal Current | - | 7~20mA |
| Signal Isolation | N | Photocoupler |
| Power | Single | Single/Dual |
4.3. Dimensions
- PCBA Board Dimensions: 39.00mm x 31.50mm
- Mounting Hole Diameter: φ3.2mm x 4
- PCBA Thickness on Motor: Approximately 10.5mm from the motor face and 3mm from the motor back.
5. Setup and Installation
5.1. Wiring
Connect the MKS SERVO42C PCBA to your controller board using the provided cables. Ensure correct polarity and pin assignments. The diagram below illustrates the wiring for the MKS SERVO42C_OC version, which shares similar signal connections (COM, STP, DIR, EN) with the standard MKS SERVO42C.
5.2. Magnet and Magnetic Encoder Placement
Accurate placement of the radial magnet relative to the magnetic encoder chip is crucial for optimal performance and angle accuracy. Follow these guidelines:
- Maintain a gap between the magnet and the encoder chip parallel to each other, ranging from 0.5mm to 3.0mm. A smaller gap generally yields better results.
- Align the center of the magnet with the sensing center of the magnetic encoder chip. The deviation should be within ±0.3mm to avoid serious impact on absolute angle accuracy.
- Recommended radial magnet size: φ6.00mm diameter, 2.5mm height.
6. Operation
6.1. MKS SERVO42C Control Tool
The MKS SERVO42C PCBA can be configured and monitored using the dedicated Control Tool software via its USART interface. This tool allows for precise adjustment of various parameters and real-time querying of the driver's status.
6.2. Parameter Adjustment
- PID/ACC/Torque Parameters: Use the Control Tool to fine-tune the PID (Proportional-Integral-Derivative), Acceleration (ACC), and Torque parameters for optimal motor response and stability.
- Subdivision: The subdivision setting (1-256) can be adjusted either through the Control Tool or directly via physical keys on the board, if available.
- Motor Control: The tool allows you to enable/disable the driver, control motor rotation direction (forward/reverse), set speed, and define the number of pulses.
6.3. Zero Position Setting
To set the motor's zero position, manually turn the motor shaft to the desired zero point. Then, within the Control Tool software, click the 'OK' button in the '0_Zero' section to register this position.
6.4. Factory Reset
A factory reset option is available within the Control Tool. After performing a factory reset, it is necessary to power cycle the device for the changes to take effect.
7. Maintenance
- Keep the PCBA clean and free from dust and debris. Use a soft, dry brush or compressed air for cleaning.
- Avoid exposing the board to moisture or extreme temperatures.
- Regularly check all connections to ensure they are secure.
- Ensure adequate ventilation around the driver during operation to prevent overheating.
8. Troubleshooting
8.1. Common Issues and Solutions
- Motor not responding or losing steps:
- Check all wiring connections for proper seating and polarity.
- Verify the magnet and magnetic encoder distance and alignment (refer to Section 5.2).
- Ensure the operating voltage is within the specified 7-28V range.
- Adjust current and PID parameters using the Control Tool.
- Firmware compatibility with 3D printer:
- The need for firmware changes depends on your 3D printer's existing firmware and previous driver settings. If you are using non-TMC drivers, no modification might be needed. Consult your printer's documentation or manufacturer for specific requirements.
- Control Tool connection issues:
- Ensure the correct COM port is selected and the baud rate is set to 38400 in the Control Tool.
- Verify the USB-to-USART converter is properly installed and recognized by your computer.
9. User Tips
- When integrating with a 3D printer, check your printer's firmware for driver compatibility. If you are replacing non-TMC drivers, firmware modifications may not be necessary.
- Pay close attention to the magnet and encoder alignment during installation. Precise placement within the recommended 0.5-3.0mm gap and ±0.3mm center deviation is critical for accurate closed-loop control.
- Utilize the MKS SERVO42C Control Tool for initial setup and ongoing diagnostics. It provides comprehensive control over PID, acceleration, torque, and subdivision settings, allowing for fine-tuning to your specific motor and application.
10. Support and Resources
For further technical information, firmware updates, and community support, please refer to the following resources:
- GitHub Repository (includes Control Tool): https://github.com/makerbase-mks/MKS-SERVO42C
- Makerbase YouTube Channel: https://www.youtube.com/channel/UC2i5I1tcOXRJ2ZJiRxwpCUQ/videos
