SCA61T Series
C SB
S C K
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
17
18
16
C O M M A N D
M O S I
D A T A O U T
H IG H IM PE D A N C E
M IS O
9
8
7
6
5
4
3
2
10
1
0
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 data register are in 11 bit digital word format. The
data range is from 0 to 2048. The nominal content of RDAX data register in zero angle position is:
Binary: 100 0000 0000
Decimal: 1024
The transfer function from differential digital output to angle can be presented as
D
[
LSB
]
− Dout@0°
LSB
]
⎛
⎜
⎜
⎝
⎞
⎟
⎟
⎠
out
α = arcsin
Sens LSB/g
[
]
where;
Dout
digital output (RDAX)
Dout@0° digital offset value, nominal value = 1024
α
Sens
angle
sensitivity of the device. (SCA61T-FAHH1G: 1638, SCA61T-FA1H1G: 819)
As an example following table contains data register values and calculated differential digital
output values with -5, -1 0, 1 and 5 degree tilt angles.
Angle
[°]
Acceleration
[mg]
RDAX (SCA61T-
FAHH1G)
RDAX (SCA61T-
FA1H1G)
-5
-87.16
dec: 881
dec: 953
bin: 011 0111 0001
dec: 995
bin: 011 1110 0011
dec: 1024
bin: 011 1011 1001
dec: 1010
bin: 011 1111 0010
dec: 1024
-1
0
-17.45
0
bin: 100 0000 0000
dec: 1053
bin: 100 0001 1101
dec: 1167
bin: 100 0000 0000
dec: 1038
bin: 100 0000 1110
dec: 1095
1
17.45
87.16
5
bin: 100 1000 1111
bin: 100 0100 0111
VTI Technologies Oy
www.vti.fi
Subject to changes
Doc. nr. 8261900
12/18
Rev.A
VTI [ VTI TECHNOLOGIES ]
