[WT901C] 9-Axis Inclinometer MPU9250, Acc, Gyro, Angle, Digital Compass, (X±0.2°, Z±1°）

When the configuration interface is offline, configuration changes cannot be applied. Please check the following:

a. The RX pin on the TTL Serial interface may have poor contact, causing command transmission failure. Check the wiring and solder joints.

b. The current Baud Rate is too low or the data rate is too fast. Click "Re-read Configuration" on the configuration page.

c. The selected device model in the PC software does not match the actual device. Choose the correct model to read the configuration.

d. The PC software version may be outdated. Click "Update PC software" under the Help section.

e. The serial port is connected to an external microcontroller. Erase the microcontroller program to restore normal serial communication.

There are several possible reasons:

1. The power supply is not standard; stable 3.3V to 5V Operating Voltage is required.
2. The module is not properly soldered or the test clips are not stable, leading to poor contact.
3. The wiring has connectivity issues, such as internal breaks, causing communication or power failure.
4. The adapter interface level does not match our module's 3.3V level, causing compatibility issues.
5. Hardware abnormality in the product.
6. Firmware/program abnormality in the product.

If the wiring checks out, use a serial port tool to check if the raw data is normal.

After calibration, the sensor still shows 1g of data. This 1g is the gravitational acceleration. As the module is placed horizontally with the Z-axis pointing upward and stationary, gravity points downward, so the sensor measures an upward force equal to gravity, resulting in 1g (positive direction).

An Inertial Sensor measures all accelerations acting on the object, including the 1G gravitational acceleration. This cannot be automatically removed as it is a real physical value. To remove it, use the Quaternion Output to obtain the real-time attitude, and then subtract the gravitational component in the vertical direction.

1. For 6-DOF products or 6-axis algorithms: Using our Kalman Filter, the X and Y axes do not drift. The Z-axis does not drift in a static state, but accumulates error during motion. Since the Z-axis Angle is calculated by integrating Angular Velocity without a filtering observation, drift is unavoidable. The X and Y axes use gravity field filtering to eliminate drift.

The Z-axis can only be used for relative short-term measurement, calculating the rotated angle from the difference between two consecutive angles. Periodic zero-setting commands are required; please refer to the communication protocol for details.

2. For 9-axis algorithms: The Z-axis Angle is calculated using Magnetic field data. Once there are ferromagnetic objects (iron, cobalt, nickel) nearby, magnetic interference will occur, causing inaccurate angles. Avoid magnetic interference during installation. Minor interference can be corrected with magnetic calibration. (Our products are calibrated in a magnetically shielded barrel at the factory; generally, users do not need to perform calibration and can just avoid interference.)

Note: For long-term Z-axis Angle applications, a 9-DOF sensor is recommended. If only the Z-axis angle is needed in a planar environment, the HWT101 is recommended.