SCA103T Series
CSB
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
SCK
COM M AND
M OSI
DATA OUT
10
9
8
7
6
5
4
3
2
1
0
H IG H IM P E D A N C E
M IS O
Figure 11.
Command and 11 bit acceleration data transmission over the SPI
2.5
Digital Output to Angle Conversion
The acceleration measurement results in RDAX and RDAY data registers are in 11 bit digital word
format. The data range is from 0 to 2048. The nominal content of RDAX and RDAY data registers
in zero angle position are:
Binary: 100 0000 0000
Decimal: 1024
To obtain the differential digital output value, Dout, RDAY must be subtracted from RDAX.
Dout =
RDAX – RDAY
The transfer function from differential digital output to angle can be presented as
α
=
arcsin
⎜
⎜
where;
D
out
⎛
D
out
[
LSB
]
−
D
out
@ 0
°
[
LSB
]
⎞
⎟
⎟
Sens
[
LSB/g
]
⎝
⎠
differential digital output (
RDAX – RDAY)
digital offset value, nominal value = 0 in differential mode
angle
sensitivity of the device
. (SCA103T-D04: 6554, SCA103T-D05: 3277)
α
D
out@0°
Sens
As an example, the following table contains SCA103T-D04 data register values and calculated
differential digital output values with -5, -1 0, 1 and 5 degree tilt angles.
Angle
[°]
-5
-1
0
1
5
Acceleration RDAX
[mg]
-87.16
dec: 739
bin: 010 1110 0011
-17.45
dec: 967
bin: 011 1100 0111
0
dec: 1024
bin: 100 0000 0000
17.45
dec: 1081
bin: 100 0011 1001
87.16
dec: 1309
bin: 101 0001 1101
RDAY
dec: 1309
bin: 101 0001 1101
dec: 1081
bin: 100 0011 1001
dec: 1024
bin: 100 0000 0000
dec: 967
bin: 011 1100 0111
dec: 739
bin: 010 1110 0011
DOUT
(RDAX–RDAY)
dec: -570
dec: -144
dec: 0
dec: 114
dec: 570
VTI Technologies Oy
www.vti.fi
Subject to changes
Doc.Nr. 8261700
13/19
Rev.A
VTI [ VTI TECHNOLOGIES ]
