SCA121T Series
Murata Electronics Oy Subject to changes 1/5
www.muratamems.fi Doc.Nr. 82 1274 00 Rev.A
THE SCA121T DUAL AXIS INCLINOMETER MODULES
The SCA121T Series contain 3D-MEMS-based dual axis inclinometer modules that provide instrumentation grade
performance for leveling applications in harsh environment. The measuring axes of the sensing elements are
parallel to the mounting plane and orthogonal to each other. Low temperature dependency, high resolution and
low noise, together a with robust sensing element design, make the SCA121T the ideal choice for leveling
instruments. The Murata inclinometers are insensitive to vibration, due to their over damped sensing elements,
and can withstand mechanical shocks of up to 20000 g.
Features
Dual axis inclination measurement (X and Y)
Measuring ranges ±30° and ± 90°
0.0025° resolution (10 Hz BW, analog output)
Sensing element controlled over damped
frequency response (-3dB 18Hz)
Robust design, high shock durability (20000g)
High stability over temperature and time
Single +5 V supply and unregulated 7…35V
supply
RoHS compliant
Applications
Platform leveling and stabilization
360° vertical orientation measurement
Leveling instruments
Construction levels
Product Family Specification
Data Sheet
SCA121T Series
Murata Electronics Oy Subject to changes 2/5
www.muratamems.fi Doc. nr. 82 1274 00 Rev.A
TABLE OF CONTENTS
The SCA121T Dual Axis Inclinometer modules ..................................................................... 1
Features............................................................................................................................................. 1
Applications ...................................................................................................................................... 1
Table of Contents...................................................................................................................... 2
1 Electrical Specifications ..................................................................................................... 3
1.1 Absolute Maximum Ratings ................................................................................................... 3
1.2 Performance Characteristics .................................................................................................. 3
1.3 Electrical Characteristics ....................................................................................................... 4
1.4 Electrical Connection.............................................................................................................. 4
2 Functional Description ....................................................................................................... 4
2.1 Measuring Directions .............................................................................................................. 4
2.2 Voltage to Angle Conversion ................................................................................................. 4
2.3 Ratiometric Output .................................................................................................................. 5
3 Mechanical Specifications .................................................................................................. 5
3.1 Sensor dimensions ................................................................................................................. 5
SCA121T Series
Murata Electronics Oy Subject to changes 3/5
www.muratamems.fi Doc. nr. 82 1274 00 Rev.A
1 Electrical Specifications
The SCA121T product family comprises three versions, the SCA121T-D03, the SCA121T-D05 and
the SCA121T-D07 that differs in measurement range and supply voltage. The product version
specific performance specifications are listed in the table SCA121T performance characteristics
below.
1.1 Absolute Maximum Ratings
Supply voltage SCA121T-D05(VDD)
Supply voltage SCA121T-D03 and D07
Voltage at input / output pins
Storage temperature
Operating temperature
Mechanical shock
Regulated -0.3 V to +5.5V
Unregulated -0.3 V to +35V
-0.3V to 5.3
-55°C to +125°C
-40°C to +125°C
Drop from 1 meter onto a concrete surface
(20000g). Powered or non-powered
1.2 Performance Characteristics
Parameter
Condition
SCA121T
-D05
SCA121T
-D07
Units
Measuring range
Nominal
±90
±1
±90
±1
±30
±0.5
°
g
Supply Voltage
7…35
5±0.25
7…35
V
Offset (Output at 0g)
2.5
Vdd/2
2.5
V
Offset calibration error
Max deviation
±1.5
±1.5
±1.5
°
Sensitivity
between 0…1° (1
2
35
2
35
4
70
V/g
mV/°
Sensitivity calibration
error
±1.5
±1.5
±1.5
%
Offset temperature
dependency
-25…85°C
±1
±1
±1
°
0…70°C
±0.5
±0.5
±0.5
°
Sensitivity temperature
dependency
-25...85°C
-1.5...+0.5
-1.5...+0.5
-1.5...+0.5
%
0…70°C
-0.8...+0.3
-0.8...+0.3
-0.8...+0.3
%
Typical non-linearity
Measuring range
N/A
N/A
±0.57
°
Frequency response
–3dB LP (2
8-28
8-28
8-28
Hz
Ratiometric error
Vdd = 4.75...5.25V
±1
%
Cross-axis sensitivity
Max.
4
4
%
Note 1. The angle output has SIN curve relationship to voltage output
Note 2. The frequency response is determined by the sensing element’s internal gas damping.
SCA121T Series
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www.muratamems.fi Doc. nr. 82 1274 00 Rev.A
1.3 Electrical Characteristics
Parameter
Condition
Min.
Typ
Max.
Units
Current consumption
Vdd = 5 V; No load
5
8
mA
Operating temperature
-25
+85
°C
Analog resistive output load
Vout to Vdd or GND
10
kOhm
Analog capacitive output load
Vout to Vdd or GND
20
nF
Start-up delay
Reset and parity check
10
ms
1.4 Electrical Connection
Wire Color
Name
Function
Blue
GND
Ground
Red
Vdd
Power supply
Yellow
Out X
X-axis output
Green
Out Y
Y-axis output
White
NC
Not Connected
2 Functional Description
2.1 Measuring Directions
Figure 1. The measuring directions of the SCA121T
2.2 Voltage to Angle Conversion
Analog output can be transferred to angle using the following equation for conversion:
ySensitivit
OffsetVout
arcsin
Where: Offset = output of the device at 0° inclination position, Sensitivity is the sensitivity of the
device and VDout is the output of the SCA121T. The nominal offset is 2.5 V and the sensitivity is 4
V/g for the SCA121T-D07 and 2 V/g for the SCA121T-D03 and SCA121T-D05.
Angles close to 0° inclination can be estimated quite accurately with straight line conversion but for
the best possible accuracy, arcsine conversion is recommended to be used. The following table
shows the angle measurement error if straight line conversion is used.
SCA121T Series
Murata Electronics Oy Subject to changes 5/5
www.muratamems.fi Doc. nr. 82 1274 00 Rev.A
ySensitivit
OffsetVout
Straight line conversion equation:
Where: Sensitivity = 70mV/° with SCA121T-D07 or Sensitivity= 35mV/° with SCA121T-D03 and
SCA121T-D05
Tilt angle [°]
Straight line conversion error [°]
0
0
1
0.0027
2
0.0058
3
0.0094
4
0.0140
5
0.0198
10
0.0787
15
0.2185
30
1.668
2.3 Ratiometric Output
Ratiometric output means that the zero offset point and sensitivity of the sensor are proportional to
the supply voltage. If the SCA121T-D05 supply voltage is fluctuating the SCA121T-D05 output will
also vary. When the same reference voltage for both the SCA121T-D05 sensor module and the
measuring part (A/D-converter) is used, the error caused by reference voltage variation is
automatically compensated for.
3 Mechanical Specifications
Cable length: -D03,-D07 30cm
-D05 110cm
Cable type: UL/CSA listed, PUR black
Cable diam.: 6±0.2mm
Leads: 5 x 0.14mm2
Total weight: Approx. 60 grams
Protection class: IP66
Housing: Zinc casting with passivation
Mounting: The sensor module is to be mounted on a flat and smooth surface
with 2 screws, dimension M4. Mounting torque 5 ±1Nm
3.1 Sensor dimensions
Figure 2. Mechanical dimensions of the SCA121T (Dimensions in mm)