SCA3000-D01 datasheet(8/43 Pages) VTI

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SCA3000 Series

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Doc.Nr. 8257300A.07

Rev.A.07

Table 2. Available measurement modes for SCA3000.

Available measurement

modes

SCA3000-D01

SCA3000-D02

SCA3000-E01

SCA3000-E02

SCA3000-E04

SCA3000-E05

Default after power-on

or reset

Measurement

mode

Measurement

mode

Measurement

mode

Measurement

mode

Optional measurement

mode 1

Bypass

measurement

mode

Narrow band

measurement

mode

Narrow band

measurement

mode

Narrow band

measurement

mode

Optional measurement

mode 2

Not available

Wide band

measurement

mode

Wide band

measurement

mode

2.2.1.1

Bypass measurement mode

In bypass measurement mode, the signal bandwidth of the SCA3000 is extended by bypassing the

low-pass filter in signal channel. As a result of a wider measurement bandwidth, the noise level is

higher.

2.2.1.2

Narrow band measurement mode

In narrow band measurement mode, the signal bandwidth of the SCA3000 is reduced by increasing

low-pass filtering in signal channel. In addition, the output data rate is halved due to decimation. As

a result of a narrower signal bandwidth, the noise level is lower.

2.2.1.3

Wide band measurement mode

In wide band measurement mode, the SCA3000 signal channel low-pass filtering pass band is

widened. As a result of a wider measurement bandwidth, the noise level is higher.

2.2.2

Usage

The optional measurement modes can be enabled by setting the bits called MODE_BITS in MODE

Acceleration data can be read from data output registers X_LSB, X_MSB, Y_LSB, Y_MSB, Z_LSB

and Z_MSB in all measurement modes. Each of these registers can be read one by one or using

the decrement register read, which is described in section 4.1.3.2 for SPI and 4.2.1.3 for I

interface. See section 3.3 for output register details.

2.2.2.1

Overflow condition

Since acceleration data registers have no limiter, the possible overflow needs to be detected using

bits [B7, B6, B5]. If bits [B7, B6, B5] are ‘011’ or ‘100’, data overflow has occurred (see Table 3).

This applies for all acceleration output registers (X_LSB … Z_MSB and BUF_DATA).

Table 3. Overflow bit patterns in acceleration data registers (X_LSB … Z_MSB and BUF_DATA).

Byte

MSB byte

LSB byte

Bit number

Acceleration data bit

Sign

d11

d10

B2:B0

Data overflow on

positive acceleration

xxx

Data overflow on

negative

acceleration

xxx

x = ignore

In case of overflow, the output register value must be discarded. When an overflow is detected, the

bit pattern ‘0101 1111 1111 1xxx’ is used for positive accelerations and ‘1010 0000 0000 0xxx’ for

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