IMU : FAQ

1. The external trigger input function
The external trigger input function allows the output timing of sampling data to be controlled externally by applying an appropriate periodic pulse signal to a specific pin.

2. The external counter‑reset input function
The external counter reset input function helps time synchronization with external devices by resetting the IMU's counter value using signals such as a PPS signal for timestamping. With accurate time stamp information of the IMU data relative to GNSS time, the system can correlate the timing of the IMU data with the other external sensor data.
For configuration details, please refer to "External Trigger Input" and "External Counter Reset Input" in the datasheet.

If you would like a data sheet, please request it from Contact Form.

1. Verify that the IMU pins are correctly wired.

• Refer to "Socket Pin Assignments and Functions" in the datasheet.

2. Check the Power-On Start-Up Time described in the “Interface Specifications” section of the datasheet.

• If communication is initiated before the required time has elapsed after power-on, the IMU may not respond.

3. Confirm that the communication conditions and timing match the UART/SPI interface specifications in the datasheet.

• For UART, pay attention to the baud rate (default: 460.8 kbps).
• For SPI, ensure that the host-side SPI clock frequency, SPI clock phase/polarity , SPI wait times, and other timing parameters are set correctly.

4. Read the ID_Register listed in the datasheet and confirm that the fixed value 0x5345 is obtained.

• If the value cannot be read, there may be an issue with wiring, communication settings, or the power-up sequence.

If you would like a data sheet, please request it from Contact Form.

If you would like a data sheet, please request it from Contact Form.

1. Measurement Range:
Verify the measurement ranges for angular velocity and acceleration, and select a device that is suitable for the operating range required by the intended application.
2. Accuracy Requirements:
Check whether specifications such as bias stability and angle random walk meet the required accuracy.
3. Output Rate:
Confirm that the device supports the necessary sampling frequency (up to 2 ksps).
4. .Interface:
Select an interface suitable for your system, such as UART, SPI, RS422, or CAN.
5. .Environmental Conditions:
Verify the operating temperature range and protection features such as waterproof/dustproof ratings (e.g., IP67).

1. Confirm the CAN communication bit rate described in the datasheet, and ensure that the device is connected using the same bit rate.
2. CAN ID settings: If the default Node ID (NID = 01h) has been changed, verify that communication is being performed with the correct ID.
3. If the LED indicator is blinking red, make sure the device is properly connected to the host through the CAN cable, then power‑cycle the device.
4. When reading from or writing to the Object Dictionary (OD), please note that multi‑byte data uses little‑endian byte order.
5. For CANopen IMUs, some functions such as Object Dictionary read/write access or TPDO messages are restricted. Refer to "Table 5.7 Valid Function of Each NMT State" described in the datasheet for available functions. Send the NMT command to place the CANopen IMU into Pre-operational (OD access) or Operational (OD or TPDO) state. The CANopen IMU's current NMT state is indicated in the Hearbeat message (if enabled), or by decoding the Run LED (Green) blinking pattern (see Table 5.17 Run LED (Green) Status in the datasheet).

If you would like a data sheet, please request it from Contact Form.

If you would like a data sheet, please request it from Contact Form.

1. Allowing sufficient warm‑up time:

Providing adequate warm‑up time helps the bias stabilize.

2. Stabilizing the temperature environment:

Temperature variations are a major factor contributing to drift.
Using the device in as stable a temperature environment as possible is recommended.

1. Check the connection between the PC and the USB evaluation board:

Ensure that the PC is properly connected to the USB evaluation board and that the red LED on the evaluation board is lit.

2. Verify the FTDI driver:

Confirm in the Device Manager that the board is recognized as a USB Serial Port.
If it is not recognized, reinstall the FTDI driver.
(IMU_LoggerSoftware_UserGuid, Page 6.)

3. Configure the COM port settings:

In the Config screen, set the SerialSetting → Port to match the COM number shown in the Device Manager.
(IMU_LoggerSoftware_UserGuid, Page 8.)

4. Check the logger version:

Make sure you are using the latest version of the evaluation software"IMU Logger". Older versions may not support newer IMU models.

1. GitHub

Python sample code (py_esensorlib), driver code for Arduino, and IMU drivers for ROS1/ROS2 are available.

2. Sample Code:

The datasheet includes UART/SPI communication sequences and sample C code.

3. Evaluation Tools:

The IMU Logger software (Windows) is available free of charge.
However,the DLL specifications and APIs are not disclosed.

4. Linux Environments:

For use on Linux platforms such as Raspberry Pi, please refer to the sample code available on GitHub.
Although we do not provide samples for specific development environments such as LabVIEW, implementation is possible based on the UART/SPI communication specifications.

GitHub:link

If you would like a data sheet, please request it from Contact Form.

1. Recommended torque:

Although no specific recommended torque value is defined for the M2 mounting screws of the IMU, avoid excessive tightening. As a guideline, a hand‑tightened level sufficient to secure the unit (approximately 0.2–0.3 N·m) is appropriate.

2. Mounting hole specifications:

Using the diagonal mounting holes helps maintain the directional accuracy of the sensor axes. Refer to the dimensional drawing in the datasheet for details on hole diameter and positional tolerances.

3. Use of washers:

Washers may be used without issue; however, ensure that the bottom surface of the IMU remains parallel to the mounting surface.

4. Impact of positional misalignment:

Misalignment during tightening of the M2 screws may affect data accuracy. If higher precision is required, consider using positioning pins to help maintain mechanical alignment to the mounting surface's reference frame.

1. Sensor origin location

The sensor origin (accelerometer origin) is defined as the coordinate origin shown in the external dimension drawing of the datasheet. It is typically located near the center of the bottom surface of the housing.

2. Misalignment

Individual errors between the external reference surfaces and the detection axes are not specified. For the inter‑axis misalignment values, please refer to the Misalignment parameters in the “Characteristics and Electrical Specifications” section of the datasheet.

3. Coordinate markings

The coordinate axis markings printed on the IMU surface indicate the directions of the detection axes.

4. Relationship to mounting holes

The distances from the mounting holes to the sensor origin are provided in the dimensional drawings of the datasheet.

If you would like a data sheet, please request it from Contact Form.

1. Evaluation Criteria

Gyroscope:
The bias value at rest must be within internal limits.
Accelerometer:
The magnitude of the three‑axis acceleration vector must fall within an internal defined range.

2. Actions to Take if an Error Occurs

2.1. Verify the Environment and Retry
Ensure that there is no vibration, movement, or impact, and run the self‑test again in a completely stationary condition.

2.2. About IMU Operation
Even if the self‑test results in NG (fail), the IMU will continue to operate (including the ability to switch to UART automatic mode).
However, in this case, sensor accuracy may not be guaranteed.

2.3. If the Issue Persists
If NG continues after multiple attempts, a sensor malfunction may be suspected.
In such cases, please consider replacing the unit.