 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
ADIS16385 Datasheet(PDF) 16 Page - Analog Devices |
|
||||||||||||||||||||||||||||||
ADIS16385 Datasheet(HTML) 16 Page - Analog Devices |
|
|
16 / 20 page  ADIS16385 Preliminary Technical Data Rev. PrA | Page 16 of 20 CALIBRATION The mechanical structure and assembly process of the ADIS16385 provide excellent position and alignment stability for each sensor, even after subjected to temperature cycles, shock, vibration, and other environmental conditions. The factory calibration includes a dynamic characterization of each sensor’s behavior over temperature and generates sensor-specific correction formulas. The bias correction registers in Table 30 provide users with the ability to address bias shifts that can result from mechanical stress. Figure 19 illustrates the summing function of each sensor’s offset correction register. Table 30. Registers for User Calibration Register Address Description XGYRO_OFF 0x1A Gyroscope bias, x-axis YGYRO_OFF 0x1C Gyroscope bias, y-axis ZGYRO_OFF 0x1E Gyroscope bias, z-axis XACCL_OFF 0x20 Accelerometer bias, x-axis YACCL_OFF 0x22 Accelerometer bias, y-axis ZACCL_OFF 0x24 Accelerometer bias, z-axis GLOB_CMD 0x3E Automatic calibration Figure 19. User Calibration, XGYRO_OFF Example There are two options for optimizing gyroscope bias accuracy prior to system deployment: automatic bias correction (ABC) and manual bias correction (MBC). Automatic Bias Correction (ABC) Set GLOB_CMD[0] = 1 (DIN = 0xBE01) to start the ABC function, which uses the following internal sequence to calibrate each gyroscope for bias error: 1. Set the output range to ±75°/sec and wait for a complete output data cycle to complete (the SMPL_PRD[12:8] bits set this time). 2. Read the output register of the gyroscope. 3. Multiply the measurement by −1 to change its polarity. 4. Write the final value into the offset register. The Allan Variance curves in Figure 7, Figure 9, and Figure 8 provide a trade-off between bias accuracy and averaging time. SMPL_PRD[12:8] provide a user control for averaging time when using the ABC function. Use this setting, in combination with GLOB_CMD[0], to create the automatic bias correction function. ABC Example Set SMPL_PRD[15:8] = 0x10 (DIN = 0xB710) to set the decimation rate to 65,536 (216), which provides an averaging time of 64 seconds (65536 ÷ 1024 SPS) for this function. Then, set GLOB_CMD[0] = 1 (DIN = 0xBE01) and keep the platform stable for at least 65 seconds while the gyroscope bias data accumulates. After this completes, the ADIS16385 automatically updates the flash memory. The SPI is inactive and does not respond to user inputs while the ABC is processing. The only way to interrupt it is to remove power or initiate a hardware reset using the RST pin. When using SMPL_PRD[12:8] = 0x10, the 1-σ accuracy for this correction is approximately 0.008°/sec for the X-axis and Y-axis gyroscopes and 0.003°/sec for the Z-axis gyroscope. See Table 15 for more information on GLOB_CMD. Manual Bias Correction The manual bias correction (MBC) function requires the user to collect the desired number of samples, calculate the averages to develop bias estimates for each gyroscope channel, and then write them into the bias offset registers, located in Table 31 for the gyro- scopes. For example, set XGYRO_OFF = 0x1FF6 (DIN = 0x9B1F, 0x9AF6) to adjust the XGYRO_OUT offset by −0.03125°/sec (−10 LSBs). Table 32 provides a manual adjustment function for the accelerometer channels as well. Table 31. XGYRO_OFF, YGYRO_OFF, and ZGYRO_OFF Bit Descriptions Bits Description (Default = 0x0000) [15:0] Twos complement, 0.003125°/sec per LSB. Typical adjustment range = ±102°/sec. Table 32. XACCL_OFF, YACCL_OFF, and ZACCL_OFF Bit Descriptions Bits Description (Default = 0x0000) [15:0] Data bits. Twos complement, 0.25 mg/LSB. Typical adjustment range = ±8.192 g. Restoring Factory Calibration Set GLOB_CMD[1] = 1 (DIN = 0xBE02) to execute the factory calibration restore function. This is a single-command function, which resets each user calibration register to 0x0000 and all sensor data to zero. Then, it automatically updates the flash memory within 50 ms. See Table 15 for more information on GLOB_CMD. Point-of-Percussion (Gyroscope) Set MSC_CTRL[6] = 1 (DIN = 0xB486) to enable this feature and maintain the factory-default settings for DIO1. This feature performs a point-of-percussion translation to the point identified in Figure 6. See Table 21 for more information on MSC_CTRL. |
Similar Part No. - ADIS16385 |
|
Similar Description - ADIS16385 |
|
|
|
Link URL |
| Privacy Policy |
| ALLDATASHEET.NET |
| Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
| Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
