SI & SA evaluation kits for high-precision inertial sensors
The SI & SA evaluation kits are inertial sensor modules
including control board, sensor board and software for
easy-to-use read-out and quick evaluation of the sensor
data. The capacitive inclinometers and accelerometers
from First Sensor are based on single crystal silicon sensor
elements and utilize state-of-the-art micromechanical
technology (HARMS, AIM) to achieve large signal-to-noise
ratios and excellent stability over temperature.
Benefits of the AIM technology
– Ultra-low cross axis sensitivity due to
HARMS technology
– Thin-film free mechanical components,
single crystal silicon based
– Minimizing of parasitic capacitances due to
insulation of the functional components by
air gap
– Complete dry processing
– Excellent thermal performance
– Large signal-to-noise ratio
– Mechanical over-damped to reduce parasitic
signals
– Customer specific measurement ranges
due to flexible adjustment of mass, spring
and damping
Features of the sensor system
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Dual axis measurement
Excellent stability over temperature
Digital SPI interface
High resolution ADC offering more than
100 dB dynamic range
Configurable bandwith output filter
Shock survival 1500 g
Hermetically sealed package
Customized sensor solutions for packaging
and signal processing
Applications
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Geoengineering
Condition monitoring
Navigation
Security systems
Platform control and stabilization
Tilt sensing and leveling
Industrial applications
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SI & SA evaluation kits for high-precision inertial sensors
Dimensional drawing and electrical connection
Caution:
The product can be damaged by incorrect connection. Please double check the cable configuration between
sensor and control board.
Control board
Pin assignment
not used
VDD (5 V)
SSN (Serial Select)
SCK (Serial Clock)
MOSI
MISO
GND
Sensor board
Pin assignment
VDD (5 V)
SSN (Serial Select)
SCK (Serial Clock)
MOSI
MISO
GND
dimensions in mm
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SI & SA evaluation kits for high-precision inertial sensors
User manual of the terminal software
The software that is used for evaluation of the sensors is a simple
terminal program and runs under Windows operating systems. In case
of using Linux as operating system please contact us. The evaluation kit
is powered using the USB interface. Therefore, no additional reference
voltage is necessary. The software is running without an installation.
However, it is necessary to install the drivers of the FT232R USB serial
converter. Please connect the sensor board “SensB01.SX-XX.S1.C-XX”
with the control board “ConB01.SX-SPI” (for the correct connections
check the pin assignment) as well as the control board with a PC. When
the new hardware is detected automatically, continue the installing
using manual selection of the drivers which are located in the folder “…/
First Sensor/driver”. The drivers are correctly installed if you have done
this procedure two times. In case that the hardware is not detected au-
tomatically, it is recommended to use the device manager for selecting
the unknown hardware and installing of the required drivers.
Other software, for instance specialized measurement programs, can
also be used if they are capable of sending and receiving correct com-
mand strings. Each command string send from the controlling computer
has to be terminated by a CR-LF sequence (Carriage Return, Line Feed,
0x0D0A). Commands that are not terminated with his sequence are not
recognized as valid by the microcontroller. The microcontroller responds
to valid commands by executing the requested commands and sending
a response string, also terminated with CR-LF sequence. For communi-
cation with the control board “ConB01.SX-SPI” it is necessary to setup
correct parameters for the additional COM-port. After starting the
program using “HTerm.exe” please verify that the preconfigured para-
meters are selected as shown in Figure 1. The correct COM port that is
used for the evaluation kit is obtained by using the device manager of
the PC.
Select COM Port
and connect
Baudrate: 57600
Data Bits: 8
Stop Bit: 1
Parity: NONE
Newline characters: CR+LF
Fig. 1: Control panel of the terminal software and selection of the COM-port parameters
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SI & SA evaluation kits for high-precision inertial sensors
User manual of the terminal software
Clear output
data field
Saving the measurement results
Data output
Time difference of the marked measure-
ment results [hh:mm:ss] and timestamp of
the corresponding measurement value
Input of commands
Verfication that the control board is correctly connected
Fig. 2: General overview of the control panel
As shown in Figure 2 the control panel consists of two general buttons
(clearing the received data and saving the measurement results), a
data output section, a read out of the timing information as well as a
command line interface.
To store the measurements results the button “Save output” is used. The
default kind of the result file is similar to a text file format. Please note,
that the complete data of the output section is stored in the result file.
Therefore, clearing the output data field is recommended before starting
the measurement. This is done by pressing the “Clear received” button.
Furthermore, after the measurement has been finished it is possible to read
out the duration of the measurement. Using “Ctrl+a”, all data of the output
section is marked and the time difference is shown in the timing informa-
tion line. Otherwise the timestamp of the operating system could be used
to calculate the duration of the measurement. In this case it is necessary to
read out the timestamp of the first and the last measurement result.
To adjust the measurement and the sensor parameters some simple com-
mands are necessary. A list of available commands is depicted in Table 16
and shown in the data output section when the command HELP is written
in the command line and finished using the enter button.
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SI & SA evaluation kits for high-precision inertial sensors
User manual of the terminal software
Overview of available commands using the terminal software
Command
Usage/value Description
Using the following commands it is possible to configure the measurement parameters and to receive status information of the register values.
START
STOP
HELP
RSYS
RSYS
SET
PARAM
Starts output of measurement results over serial interface. Output values will be the current chip temperature and the current acceleration
of the selected axis. Please note that results are raw data, expressed in [LSB] and without any compensation. To convert the raw data into a
corresponding temperature in [°C] or acceleration in [g] please see chapter “5.3 First Measurements”.
Stops output of measurement results over serial interface.
A list of all available commands and their usage is shown.
Read the 32 bit data from the corresponding address of the system register. The kind of input is RSYS ADD value.
List of all system register values. The kind of input is RSYS ALL.
SETA or SETB is used to select the sensitive direction of the sensor. Up to now, simultaneous read out of both sensor channels is not possible.
However, you can switch between the two channels using the command SETvalue (value A or B is written without space).
List of the configured sensor settings and the corresponding values of the registers. The kind of input is PARAM LIST.
The command PARAM AVG is used to control the averaging factor as well the output data rate of the evaluation kit. Allowed values are 1…255.
Default value is 1 leading to an output data rate of about 100 Hz in case of using default values of OBW and DSE. Due to the USB interface
200 Hz is the maximum output data rate. To calculate the output data rate equation (4) is used (see chapter “4.3 Filter and Output Data Rate
Registers”). If you exceed the maximum output data rate of 200 Hz by configuring OBW and DSE, please use PARAM AVG to decrease the
output data rate of the evaluation kit. Usually the noise of the sensor is proportional to the square root of the output data rate. The kind of input
is PARAM AVG value.
Sets the number of measurement points. Allowed values are 0…50000. If 0 (default value) is set, the sensor does continuous measurements. The
kind of input is PARAM NR value.
Enables the low voltage mode. Allowed values are 0 (normal operation) or 1 (low voltage mode using 1.2V measurement voltage (default: 1 (SI)
and 0 (SA))
ADD
ALL
A or B
LIST
PARAM
AVG
PARAM
LVM
NR
To configure the sensor settings the command WSYS is used. The usage of the command refers to the adjusted register name and possible values are also described
in chapter “4. Description of System Registers”. The kind of input is WSYS usage value.
WSYS
WSYS
WSYS
WSYS
WSYS
WSYS
WSYS
WSYS
WSYS
WSYS
WSYS
WSYS
WSYS
DOS
OBW
DSE
CLK
VREF
GAIN1
GAIN2
ADCA
ADCB
OFTA
OFTB
Configures the Filter Decimation Output selection. Allowed values are 0 = normal output, 1 = DCF is bypassed and 2 = DCF and HBF are
bypassed. (default: 0)
Configures the Filter Decimation Factor. Usually changing the Filter Decimation Factor during operation requires a resetting. However, this is
done automatically. Allowed values are 0…7 (default: 3).
Configures the Down Sampling Factor and determines the ration between the output bandwidth and the output data rate. Allowed values are 0
and 1 (default: 0)
Configures the Sampling Frequency of the excitation voltage. Allowed values are 1…127 (default: 100)
Configures the Voltage Reference required for driving the sensors excitation. The voltage can output 2.1V and up to 4.4V that is adjusted using
allowed values between 0…15 (default: 0)
Configures the Sense Gain Control 1 of both sensor channels. Allowed values are 2…15 (default: 11 (SI) and 12 (SA), should be adjusted to
application specific value)
Configures the Sense Gain Control 2 of both sensor channels. Allowed values are 0…7 (default: 5 (SI) and 2 (SA), should be adjusted to
application specific value)
ADC digital Gain of Channel SetA. Allowed values are 0…524288 (default: 500)
ADC digital Gain of Channel SetB. Allowed values are 0…524288 (default: 500)
Offset Trimming of Channel SetA by adjusting the positive terminal, the negative terminal is configured automatically. Allowed values are
3141…8191 (default: 5667)
Offset Trimming of Channel SetB by adjusting the positive terminal, the negative terminal is configured automatically. Allowed values are
3141…8191 (default: 5667)
SF0, SF1,
Coefficients of Scale Factor, Bias and nominal temperature in quadratic equation. Nominal temperature is 64 times higher than the raw data of
SF2, B0, B1,
the temperature sensor in normal operation mode. (see Table 15 for allowed values)
B2, T0
CSEL
Sensor output selection (1 = normal output, 0 = calibrated output using the temperature coefficients).
