ADIS1644XSLASHFLEX datasheet(19/23 Pages) AD

19 / 23 page

Data Sheet

ADIS16446

Rev. 0 | Page 19 of 23

Accelerometer Bias Error Estimation

Under static conditions, orient each accelerometer in positions

where the response to gravity is predictable. A common approach

to this is to measure the response of each accelerometer when

each is oriented in the peak response position, that is, where

±1 g is the ideal measurement position. Next, average the +1 g

and −1 g accelerometer measurements together to estimate the

residual bias error. Note that using more points in the rotation

can improve the accuracy of the response.

Accelerometer Bias Correction Factors

When the bias estimate is complete, multiply the estimate by

−1 to change its polarity, convert it to the digital format for the

offset correction registers (see Table 33, Table 34 or Table 35)

and write the correction factors to the correction registers. For

example, lower the x-axis bias by 12 LSB (10 mg) by setting

XACCL_OFF = 0xFFF4 (DIN = 0xA1FF, 0xA0F4).

Point of Percussion Alignment

Set MSC_CTRL, Bit 6 = 1 (DIN = 0xB446) 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 21. See Table 24 for more information on MSC_CTRL.

ORIGIN ALIGNMENT

REFERENCE POINT

SEE MSC_CTRL, BIT 6.

Figure 21. Point of Percussion Physical Reference

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