Accelerometer user manual

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2 Index Page Revision Date Note V1.3 Catalogue 1. Introduction Electrical connection Dimensions Specifications Accelerometer Installation How to calibrate the 3- axis acceleration EcoCAL Installation and Communication Add Variables Measure the variables Recording Measure Value and Calculate Offset Modify Calibrations and Burn to ECU g value Calibration Angle Calibration CAN Broadcast CAN ID Broadcast Rate of CAN CAN Broadcast Enable Appendix A Calibration and Measured Values Appendix B CAN communication protocol

1. Introduction Accelerometer user manual_v1.3 The ECOTRONS accelerometer is an advanced triaxial accelerometer. It can measure the triaxial acceleration and triaxial angular velocity.

3 1. Introduction Accelerometer user manual_v1.3 The ECOTRONS accelerometer is an advanced triaxial accelerometer. It can measure the triaxial acceleration and triaxial angular velocity. And the angular velocity also can be changed into roll angle and pitch angle. The ECOTRONS accelerometer is based on the modern LSM303D and MPU6050 solutions. The LSM303D can provide accurate forward direction, and also provides proud high-accuracy sensing, extended magnetic range and the smallest measurement noise. The MPU6050 can also accurately output acceleration and angular velocity. And the ECOTRONS accelerometer can accurately output -16 to +16g linear acceleration. It can also output the accurate triaxial attitude data after the complex kinetic calculation and dynamic kalman data Fusion Filter Algorithm. 3

4 2. Electrical connection Accelerometer user manual_v1.3 The ECOTRONS Accelerometer has four wires. The wires assignments are as follows: Color Signal Description Red +12V +12V Power supply (9~16V) Black GND Ground Green CAN-H CAN bus high Yellow CAN-L CAN bus low 3. Dimensions The size of the device is as follows: 4

4. Specifications Detailed specifications Value Unit Size 73 x 39 x 26 mm Weight 70 gram Range ±16 g Accuracy 0.

5 4. Specifications Detailed specifications Value Unit Size 73 x 39 x 26 mm Weight 70 gram Range ±16 g Accuracy g Axial measurement X,Y,Z Data output frequency 100 Hz Power supply 9 ~ 16 V Operating temperature -40 ~ 85 Note: X direction: the direction of the vehicle forward. Y direction: Y-axis direction is perpendicular to the X-axis direction on the vehicle running plane. Pitch angle: the angle between the X axis and horizontal. Roll angle: the angle between the Y axis and horizontal. Accelerometer does not include a 120Ω termination resistor. 5

6 5. Accelerometer Installation Accelerometer user manual_v1.3 The accelerometer should be installed as close to the vehicle s centerline as possible. And fix it on the vehicle with two screw. Please ensure the vehicle is on flat and level ground when the accelerometer is installed. When installing the accelerometer, please make sure has one axis aligned with the vehicle s direction of motion. And another axis perpendicular to this. Checking the installation. The vehicle is stationary, the acceleration of the X axis and Y axis value is 0g, the third axis is 1g. In linear acceleration, only the axis aligned with the direction of travel has change. 6. How to calibrate the 3- axis acceleration 6.1 EcoCAL Installation and Communication The Accelerometer calibration can be achieved by EcoCAL software. EcoCAL can measure varibles and record data. And it also support play back the recorded data. The EcoCAL user manual and software can be downloaded off the website. When you operate the communication, please choose correct CAN Device, and choose the 1000kbs. 6

lastaz varibles to 20ms. These variables are 3- axis acceleration.

7 6.2 Add Variables Right-click the gray area then select Add measurements -> New Oscilloscope window, then add lastax, lastay, lastaz varibles to 20ms. These variables are 3- axis acceleration. (How to add variables can refer to EcoCAL user manual Chapter3.2). 7

8 6.3 Measure the variables Click and observe the 3 variables waveforms: 6.4 Recording Click the button, the module will slowly rotated 360 degrees along X, Y, Z three directions (be sure to rotate slowly in order to avoid an acceleration value of calibration interference). Waveform change is as follows: 8

$Then, click Open button, and go to C:\EcoCAL\record file path. Then select the latest data file. The oscilloscope only show X waveform, click show cursor/hide cursor, and toggle the cursors.$

9 6.5 Measure Value and Calculate Offset Accelerometer user manual_v1.3 Click to stop measuring. And click button to open the recorded data. Then, click Open button, and go to C:\EcoCAL\record file path. Then select the latest data file. The oscilloscope only show X waveform, click show cursor/hide cursor, and toggle the cursors. There are 2 cursors in the scope window. The values of all signals at the 2 cursor locations will be displayed in the variable list window. The cursor can be moved by mouse to other place you need. It will show the values of all the signals at the cursor locations. You need to find the waveform which is showed the minimum value and the maximum value. 9

The max value adds min value. And then divide by 2 is final result. And then input the value into the variable VAL_Acc_offset_X. (How to modify the value is descripted in next section).

10 The max value adds min value. And then divide by 2 is final result. And then input the value into the variable VAL_Acc_offset_X. (How to modify the value is descripted in next section). Then you can calibrate the Y and Z axle by same method. 6.6 Modify Calibrations and Burn to ECU First Click to stop measuring, go to "Variables -> Add calibrations" and choose the calibrations you need. Then click OK and a new table will be shown. Double click the cell and modify the value. After modifying the value, please press Enter to save your changes. Open Run button from the menu bar and choose Burn to ECU. 10

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12 7. g value Calibration Accelerometer user manual_v1.3 After the three-axis acceleration values calibrated, add the variable g_output in the 20ms variable table. Put the Accelerometer on a stable position and l the waveform of g_output. If the waveform is smoothing, the value of g_output in List is the reference value of acceleration of gravity. Input it into VAL_Acc_g. 8. Angle Calibration Add Roll_Angle_Output, Pitch_Angle_Output variables to the 20ms List, these two variables are measurement of roll angle and pitch angle. After the installation, if these two angles are not 0, you need to calibrate these two angles. Read the inaccuracy value of Roll_Angle_Output and Pitch_Angle_Output variables. And add the Roll_Angle_Output and VAL_Roll_offset calibrations, and then you will get the final result: VAL_Roll_offset (new) = VAL_Roll_offset (old) + Roll_Angle_Output VAL_Pitch_offset (new) = VAL_Pitch_offset (old) + Pitch_Angle_Output 12

3) The pitch angle is the deflection in the Y-axis direction (positive clockwise along the Y-axis is positive) 9. CAN Broadcast 9.

13 In the end, click burn to ECU, the data will be burned to ECU. Note: 1) The range of effective value of pitch angle and roll angle is -64~64 deg. 2) The roll angle is the deflection in the X-axis direction (positive clockwise along the X-axis is positive). 3) The pitch angle is the deflection in the Y-axis direction (positive clockwise along the Y-axis is positive) 9. CAN Broadcast 9.1 CAN ID You can modify these calibrations to set the CAN ID and frame type. (The content of protocol can be read in appendix B) Set the CAN ID: VAL_Angle _Broadcast_CANID VAL_Acceleration_Broadcast_CANID These two calibrations both need to be modified. 13

Set the frame type: Accelerometer user manual_v1.3 VAL_Angle_Broadcast_CANID VAL_Acceleration_Broadcast_CANID These two calibrations both need to be modified.

2 Broadcast Rate of CAN CAN broadcast rate default is 100ms (detailed protocol content can be read in the Appendix B). And broadcast rate can be modified. Unit is 10ms.

14 Set the frame type: Accelerometer user manual_v1.3 VAL_Angle_Broadcast_CANID VAL_Acceleration_Broadcast_CANID These two calibrations both need to be modified. If CANID is extended frame, these two calibrations need to be modified to 1. If CANID is standard frame, these two calibrations need to be modified to Broadcast Rate of CAN CAN broadcast rate default is 100ms (detailed protocol content can be read in the Appendix B). And broadcast rate can be modified. Unit is 10ms. VAL_Acceleration_Broadcast_Rate calibration is broadcast rate of acceleration. VAL_Angle_Broadcast_Rate calibration is broadcast rate of angle. 9.3 CAN Broadcast Enable VAL_SAEJ1939_Broadcast_En is the enable bit of CAN broadcast, 0 means disable and 1 means enable. 14

15 Appendix A Accelerometer user manual_v1.3 Calibration and Measured Values Calibration values Name VAL_Acc_offset_X VAL_Acc_offset_Y VAL_Acc_offset_Z VAL_Acc_g Description This calibration variable means the offset value of the X axis. This calibration variable means the offset value of the Y axis. This calibration variable means the offset value of the Z axis. This calibration variable means the referenced offset value of the gravitational acceleration. VAL_Pitch_offset This calibration variable means the offset value of the pitch angle. VAL_Roll_offset This calibration variable means the offset value of the roll angle. VAL_Acceleration_Broa dcast_canid VAL_Acceleration_Broa dcast_frametype This calibration variable means ID of acceleration broadcast. It can be modified and its default value is 18F This calibration variable means frame type of acceleration broadcast. 1 means extended frame, 0 means standard frame. VAL_Acceleration_Broa dcast_rate This calibration variable means the rate of acceleration broadcast. It can be modified and its default value is 100ms. Unit: 10ms VAL_Angle _Broadcast_CANID VAL_Angle_Broadcast_ FrameType This calibration variable means ID of angle broadcast. It can be modified and its default value is 18F This calibration variable means frame type of acceleration broadcast. 1 means extended frame, 0 means standard frame. VAL_Acceleration_Broa This calibration variable means the rate of acceleration 15

16 dcast_rate broadcast. It can be modified and its default value is 100ms. Unit: 10ms VAL_CAN0_BaudRate This calibration variable means the baud rate of CAN bus. 1 means baud rate of 1000K Hz, 2 means baud rate of 800K Hz, 3 means baud rate of 500K Hz, 4 means baud rate of 250K Hz, 5 means baud rate of 125K Hz, 6 means baud rate of 100K Hz, 7 means baud rate of 50K Hz, 8 means baud rate of 20K Hz, 9 means baud rate of 10K Hz, 10 means baud rate of 5K Hz. VAL_SAEJ1939_Broad cast_en This calibration variable can enable broadcast, 1 means enable and 0 means disable. Measured Value Name lastax,lastay,lastaz Description These three variables are the measured value of X, Y, Z 3-axis acceleration. X_acc This variable means the measured value of the acceleration of the vehicle. The value which is positive means that the direction of acceleration is same with vehicle driving direction. Otherwise, the value which is negative means that acceleration direction is opposite to the direction of the car. Roll_Angle_Output This variable means the measured value of the roll angle. The positive direction of the angle is the clockwise direction along the X axis. Pitch_Angle_Output This variable means the measured value of the pitch angle. The positive direction of the angle is the clockwise direction along the 16 Y axis.

17 g_output This variable means the measured value of the gravitational acceleration g. Appendix B CAN communication protocol Name J1939_PitchAng_output J1939_RollAng_output Msg ID(Hex) Rate (ms) Start Byte 3 1 Start Bit 24 8 Length (Bit) Byte Order Motorola Motorola Value Type UWORD UWORD Initial(Hex) 0 0 Factor(g) Offset(g) Signal Min Value (Phys) Signal Max Value (Phys) Signal Min Value (Hex) 0 0 Signal Max Value (Hex) Name xacc yacc zacc Msg ID(Hex) Rate (ms) Start Byte Start Bit Length (Bit) Byte Order Motorola Motorola Motorola Value Type UWORD UWORD UWORD Initial(Hex) Factor(g) Offset(g) Signal Min Value (Phys) Signal Max Value (Phys) Signal Min Value (Hex) Signal Max Value (Hex)

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