1. Introduction
The WitMotion HWT3100 is a military-grade PNI Magnetometer, functioning as a 3-axis electronic compass and geomagnetic sensor. It utilizes fluxgate technology to provide precise heading angle measurements. This manual provides essential information for the proper setup, operation, maintenance, and troubleshooting of your HWT3100 sensor.
2. Setup
The HWT3100 sensor is available with different interface options: TTL, RS485, and Type-C USB. Ensure you have the correct version for your application.
2.1 Wired Connection (TTL / RS485 Versions)
For TTL and RS485 versions, the sensor requires direct wiring to your microcontroller or system. Refer to the image below for a visual representation of the wired sensor. Always consult the official datasheet for the precise pinout and wiring diagram specific to your HWT3100 variant (TTL or RS485).
Figure 1: HWT3100 Sensor with Wired Interface (TTL/RS485)
This image displays the HWT3100 sensor module, highlighting its wired interface, typically used for TTL or RS485 communication. The colored wires indicate different connections such as power, ground, and data lines.
General Wiring Guidelines:
- Power (VCC): Connect to the appropriate power supply voltage (e.g., 3.3V or 5V, as specified in the datasheet).
- Ground (GND): Connect to the common ground of your system.
- Data Lines (TX/RX for TTL, A/B for RS485): Connect these to the corresponding data pins on your microcontroller or communication interface.
Ensure all connections are secure and correctly polarized to prevent damage to the sensor or host system.
2.2 USB Type-C Connection (Type-C Version)
The Type-C version of the HWT3100 offers a convenient plug-and-play interface for direct connection to a computer or compatible device. Refer to the image below for a visual representation.
Figure 2: HWT3100 Sensor with USB Type-C Interface
This image shows the HWT3100 sensor module connected to a USB Type-C cable, illustrating the plug-and-play interface option for direct computer connection.
Connection Steps:
- Connect one end of the USB Type-C cable to the HWT3100 sensor.
- Connect the other end of the cable to an available USB port on your computer.
- The sensor should be recognized by your operating system. You may need to install specific drivers or software provided by WitMotion for full functionality and data access.
3. Operating Instructions
The HWT3100 sensor measures the Earth's magnetic field to determine heading angle. Its operation typically involves data acquisition and processing by a host system.
3.1 Data Acquisition
- Wired Interfaces (TTL/RS485): Data is transmitted serially. Your host system (e.g., microcontroller, embedded PC) must be programmed to read data from the sensor's communication lines using the specified protocol (UART for TTL, RS485 protocol).
- USB Type-C Interface: Data is typically accessed via a virtual COM port or a dedicated software application on your computer. WitMotion usually provides software tools or SDKs for easy data access and visualization.
3.2 Calibration
Magnetometers can be affected by local magnetic disturbances. For optimal accuracy, especially in varying environments, calibration may be required. This often involves rotating the sensor through a full 360 degrees in all axes while collecting data, allowing the system to map and compensate for hard-iron and soft-iron distortions. Refer to WitMotion's documentation or software for detailed calibration procedures.
3.3 Data Interpretation
The sensor outputs 3-axis magnetic field data, which is then processed internally or by your host system to derive the heading angle. The output format (e.g., raw magnetic values, compensated heading in degrees) will depend on the sensor's configuration and the software used.
4. Maintenance
To ensure the longevity and accuracy of your HWT3100 sensor, follow these maintenance guidelines:
- Keep Clean: Regularly clean the sensor's exterior with a soft, dry cloth. Avoid using harsh chemicals or abrasive materials.
- Avoid Strong Magnetic Fields: Do not expose the sensor to strong magnetic fields (e.g., magnets, large electrical currents, motors) as this can permanently magnetize the sensor or interfere with readings.
- Physical Protection: Protect the sensor from physical shock, vibration, and extreme temperatures.
- Proper Storage: When not in use, store the sensor in a dry, dust-free environment within its specified operating temperature range.
- Cable Integrity: Periodically inspect connection cables for any signs of wear or damage. Replace damaged cables immediately.
5. Troubleshooting
If you encounter issues with your HWT3100 sensor, consider the following troubleshooting steps:
5.1 No Data Output
- Check Connections: Verify all power and data connections are secure and correctly wired according to the datasheet.
- Power Supply: Ensure the sensor is receiving the correct voltage and current.
- Drivers/Software: For USB versions, confirm that necessary drivers are installed and the communication software is correctly configured. For wired versions, check your host system's code for correct communication protocol implementation.
- Interface Type: Confirm that the sensor's interface (TTL, RS485, Type-C) matches your connection method.
5.2 Incorrect or Unstable Readings
- Magnetic Interference: Move the sensor away from potential sources of magnetic interference (e.g., power cables, motors, metal objects, other electronic devices).
- Calibration: Perform a calibration procedure as described in the operating instructions or WitMotion's software.
- Orientation: Ensure the sensor is oriented correctly relative to the Earth's magnetic field and your desired reference frame.
- Environmental Factors: Extreme temperature changes can sometimes affect sensor performance. Allow the sensor to stabilize in its operating environment.
5.3 Communication Errors
- Baud Rate/Protocol: Verify that the baud rate and communication protocol settings on your host system match those of the HWT3100 sensor.
- Cable Quality: Use high-quality, shielded cables, especially for longer runs or in noisy electrical environments.
6. Specifications
The following are general specifications for the WitMotion HWT3100 sensor. For detailed and precise specifications, always refer to the official product datasheet.
| Feature | Description |
|---|---|
| Model | HWT3100 |
| Sensor Type | 3-axis Fluxgate Geomagnetic Sensor / PNI Magnetometer |
| Output Data | Heading Angle, 3-axis Magnetic Field Data |
| Interface Options | TTL, RS485, USB Type-C |
| Dimensions (Approx.) | 15 cm (Length) x 15 cm (Width) x 5 cm (Height) |
| Weight (Approx.) | 2.0 kg |
| Origin | Mainland China |
| Hazardous Materials | None (High-concerned chemical) |
| Power Supply | (Refer to official datasheet for specific voltage range) |
| Operating Temperature | (Refer to official datasheet) |
7. User Tips
- Initial Calibration: Always perform an initial calibration of the magnetometer in its intended operating environment to achieve the best accuracy.
- Mounting: Mount the sensor securely to minimize vibrations, which can affect readings. Ensure it's away from ferrous metals or strong electromagnetic fields.
- Software Updates: Check the WitMotion website for the latest drivers, software, and firmware updates for your HWT3100 sensor.
- Environmental Awareness: Be aware that large, moving metal objects or strong electrical currents in the vicinity can temporarily or permanently affect magnetometer readings.
8. Warranty and Support
For warranty information, technical support, and access to the latest documentation (including detailed datasheets and software), please contact WitMotion directly or visit their official website. Keep your purchase records handy when seeking support.
