BW SENSING SEC380 Series User manual

SEC380 Series
Inclination compensation
3D electronic compass
Technical Manual
V3.0

SEC380
Inclination compensation
3D electronic compass
Bewis Sensing Technology LLC www.bwsensing.com Tel：[phone]
Introduction
Feature
SEC380 is a cost-effective three-dimensional electronic compass developed and produced
by Bewis Sensing. The product adopts the hard iron and soft iron calibration algorithm of Bewis
Sensing patent technology, so that it can still provide high-precision heading information when
its inclination reaches 90°. It has the advantages of small size and low power consumption, and
is suitable for miniaturized, high-precision sensitive measurement systems.
SEC380 integrates a three-axis magnetic sensor. When the heading is calculated by the
central processing unit in real time, a three-axis accelerometer is used to compensate the tilt
angle, so that it can provide accurate heading data even in extremely harsh environments. It
supports RS232, RS485 and TTL level output interfaces. The output baud rate is 2400-115200,
the output angle is 0°～360°, there are two types of hexadecimal and Modbus protocol. It can
be adapted to the needs of different application scenarios, and the electronic compass function
can be integrated into various systems very conveniently and quickly.
● Accuracy：0.5°(RMS)
● -40℃～+85℃ wide temperaturework
● Small size：L45 x W36 x H13 (mm)
● Power supply：9-36V
● Satellite tracking
● Petroleum geological survey
● Optical rangefinder
● GPS assisted navigation
● Resolution：0.1°
● Pitch/Roll：0.1°
● With hard magnetic, soft magnetic and tilt
compensation
● Standard RS232/RS485/TTL Output optional
● Individual combat equipment
● Marine survey
● Underwater navigation
● Mechanical control
Application

SEC380
Inclination compensation
3D electronic compass
Bewis Sensing Technology LLC www.bwsensing.com Tel：[phone]
Electrical Index
Performance Index
Power voltage 9-36V DC
Working current 30mA（40mA max）
Operating temperature -40℃~85℃
Storage temperature -55℃~100℃
Compass
heading
parameters
Heading accuracy
0.5°（Pitch<40°）
0.7°（Pitch<60°） 1°
（Pitch<80°）
Resolution 0.01°
Repeatability 0.1°
Compass tilt
parameters
Pitch accuracy 0.1º
Roll accuracy 0.1° for pitch ＜80°
Resolution 0.01°
Tilt range ±80°
Calibration Hard magnetic calibration
Yes
Soft magnetic calibration Yes
Limited tilt user calibration Yes
Physical
properties
Dimension L33 x W27 x H5 (mm)
Weight 25g
Output form RS232/485/TTL interface
Interface
characteristics
Start-up delay <3s
Maximum output frequency 50Hz
RS232 communication rate 2400 to 115200 baud rate
Environment Anti-vibration performance
2000g
Resolution: The smallest change value of the measured value that the sensor can detect
and distinguish within the measurement range.
Accuracy: The root mean square error of the actual angle and the sensor measuring
angle for multiple (≥16 times) measurements.
Product Feature

SEC380
Inclination compensation
3D electronic compass
Bewis Sensing Technology LLC www.bwsensing.com Tel：[phone]
PCBA size
Connector Cable socket (30cm cable)
Installation Four M2 non-magnetic screws
Product size：L45*W36*H13（mm）
Mechanical properties

SEC380
Inclination compensation
3D electronic compass
Bewis Sensing Technology LLC www.bwsensing.com Tel：[phone]
Signal
acquisition
terminal
RS485 Wiring diagram
RS232 Wiring diagram
Electronic
compass
Electronic
compass
Measurement installation
Wiring definition
Wiring color
function
RED BLUE BLACK GREEN YELLOW
1 2 3 4 5
VCC
DC 9-36V
NC GND
RXD
（B、D-）
TXD
（A、D+）
The main sensitive devices of SEC380 sensor are magnetometer and accelerometer. The
compass uses a magnetometer to sense the earth's magnetic field to calculate the sensor's
pointing, uses an accelerometer to measure the angle between the compass and gravity, and
provides inclination compensation when the compass calculates the azimuth angle. The
geomagnetic field is easily interfered by external magnetic fields. Users still need to pay
attention to the surrounding magnetic field when installing, ensure that the sensor is exposed
to the geomagnetic field, and try to avoid using it near ferromagnetic materials and changing
magnetic fields, such as engines, iron plates, Install sensors near ferrous bolts and nuts, wires,
motors, horns, and antennas. Be sure to strictly avoid magnets, motors and other strong
magnetic materials within 10cm of the compass, which may cause an irreversible decrease in
the measurement accuracy of the compass.
Electrical Interface

Bewis Sensing Technology LLC www.bwsensing.com Tel：[phone]
SEC380
Inclination compensation
3D electronic compass
Calibration
We strongly recommend to calibrate the magnetic field after the installation is complete
and after each change in the magnetic field environment. After the calibration is completed
according to the method in the manual, the firmware and program in SEC380 can effectively
eliminate the interference of the magnetic field after calibration. As long as the position of the
compass and the surrounding magnetic field environment do not change, there is no need to
compensate the sensor.
The test shows that if the user performs the calibration operation in accordance with the
requirements of the user manual, the compass can meet the above requirements when
installing, and the sensor is calibrated correctly, the heading accuracy of the sensor will be less
than 0.5 degrees (RMS). Our recommended test method is to install the SEC380 sensor
horizontally on a non-magnetic material away from the interference to measure the heading
angle. Please avoid additional magnetic field interference during the measurement.
The electronic compass has been calibrated in the factory. In places where the magnetic field
environment has little influence, there is no need to perform environmental calibration during
use, and it can be used directly. In actual use, it is recommended to calibrate.
Azimuth calibration steps:
Plane calibration:
1. Connect the product to the system and place the product in a horizontal state;
2. Open the serial debugging assistant and send 77 04 00 11 15;
3. Rotate the product in the horizontal plane (both pitch and roll angles are within ±5°) around
the z-axis (z-axis is the vertical direction), and rotate 2-3 times. The rotation process should be
as slow and close as possible Rotate at a constant speed, and the time for one revolution is
controlled between 10 seconds and 15 seconds;
4. Rotate the compass around the X-axis or Y-axis. The rotation process can be slow and nearly
uniform. It rotates 2-3 times around each axis, and the time for one rotation is about 15
seconds;
5. After completing the calibration, send 77 04 00 12 16 to save the calibration.
Multi-faceted calibration
1. Fix the electronic compass in the use environment, and try not to carry magnetic objects
such as keys and mobile phones during calibration;
2. Place the compass in a horizontal state (within ±5°);
3. Send the following calibration command in hexadecimal format: 77 04 00 08 0C, the return
value is 77 05 00 88 00 8D;
4. The product is placed in a horizontal state, the front is facing upwards (both pitch and roll
are within ±5°), the myopia rotates one circle at a constant speed, and it takes more than 10
seconds to rotate one circle;
5. The product is placed on the screen with the installation side facing up (both pitch and roll
are within ±5°), and the myopia rotates at a constant speed, and it takes more than 10 seconds
to rotate once;
6. The product is placed in a vertical position, with the smooth side of the shell facing down
(both pitch and roll are within ±5°), and the myopia rotates one circle at a constant speed, and
it takes more than 10 seconds to rotate one circle;
7. The product is placed in a vertical state, the other smooth side of the shell faces downwards
(both pitch and roll are within ±5°), and the myopia rotates at a constant speed, and it takes
more than 10 seconds to rotate once; among them, 4, 5, 6, 7 Steps can be exchanged;
8. After the four faces are rotated, send the hexadecimal command 77 04 00 09 0D to save the
calibration and return to 77 05 00 89 XX YY. Where XX represents the calibration error
coefficient, the smaller the value, the better, less than 1 is ideal, FF represents the calibration
failure, YY is the checksum of the command;
9. The calibration is complete.

Bewis Sensing Technology LLC www.bwsensing.com Tel：[phone]
SEC380
Inclination compensation
3D electronic compass
Executive standard
Product model
Communication mode
Package situation
SEC380-232 RS232 PCBA
SEC380-485 RS485 PCBA
SEC380-TTL TTL PCBA
● Enterprise Quality System Standard: ISO9001:2015 Standard (Certificate No.064-
21-Q-3290-RO-S)
● CE certification (certificate number: M.2019.103. U Y1151)
● ROHS (certificate Number: G 190930099)
● GB/T 191 SJ 20873-2003 General specification for inclinometer and level
● GBT 18459-2001 The calculation method of the main static performance index of
the sensor
● JJF 1059.1-2012 Evaluation and expression of measurement uncertainty
● GBT 14412-2005 Mechanical vibration and shock Mechanical installation of
accelerometer
● GJB 450A-2004 General requirements for equipment reliability
● GJB 909A Quality control of key parts and important parts
● GJB899 Reliability appraisal and acceptance test
● GJB150-3A High temperature test
● GJB150-4A Low temperature test
● GJB150-8A Rain test
● GJB150-12A Sand and dust experiment
● GJB150-16A Vibration test
● GJB150-18A Impact test
● GJB150-23A Tilt and rock test
● GB/T 17626-3A Radio frequency electromagnetic field radiation immunity test
● GB/T 17626-5A Surge (impact) immunity test
● GB/T 17626-8A Power frequency magnetic field immunity test
● GB/T 17626-11A Immunity to voltage dips, short-term interruptions and voltage
changes
Order information

SEC380 Series
Inclination compensation
3D electronic compass
Wuxi Bewis Sensing Technology LLC
Add：Building 30, NO. 58, Xiuxi Road, Binhu District,
Wuxi City, Jiangsu Province, China
Tel：[phone]
Mail：[email protected]
Web：www.bwsensing.com