BW SENSING BMR3300 User manual

BMR3300 Serials
Three-Axis Accelerometer
Three-Axis Magnetometer
High Accuracy Electronic Compass
Technical Manual

BMR3300
Three-Axis Accelerometer Three-Axis Magnetometer
High Accuracy Electronic Compass
The BMR3300 high-accuracy electronic compass is composed of an industrial-grade single-chip
microcomputer with high reliability and anti-interference ability, and a high-accuracy magnetic
sensor and driver chip. At the same time, it integrates the hard magnetic and soft magnetic
calibration algorithms of Bewis sensing patented technology, and compensates the tilt angle with a
three-axis accelerometer, which can provide accurate heading data in extremely harsh environments.
Through the optimized extended Kalman filter algorithm, the product outputs high-accuracy
attitude information in real time.
The BMR3000 is specifically designed to improve the static measurement accuracy of magnetic
compasses. For fixed interference, the BMR3000 can still maintain high measurement accuracy. It can
be customized according to customer requirements, and it is very convenient and quick to integrate
the electronic compass function into various products.
●Three-axis accelerometer three-axis
magnetometer
●Static measurements accuracy: 0.2°
●Offset tracking algorithm eliminates drift
●High accuracy, low cost
●Operating temperature: -40℃～+85℃
●Product size: L75 x W30.5 x H10 (mm)
●Hard magnetic, soft magnetic and tilt
compensation
●Standard RS232/RS485/TTL output interface
●Satellite tracking
●Petroleum geological exploration
●Optical range finder
●GPS-assisted navigation
●Individual combat equipment
●Ocean test
●Underwater navigation
●Mechanical control
Bewis Sensing Technology LLC www.bwsensing.com Tel：[phone]
Applications
Features
Introduction

BMR3300
Three-Axis Accelerometer Three-Axis Magnetometer
High Accuracy Electronic Compass
Compass heading
parameter
Compass tilt
parameter
Calibration
Physical
specifications
Interface
specifications
Environment
Power supply
Operating current
Operating temperature
Store temperature
9-35V DC
30mA（Max40mA）
-40~85℃
-55~100℃
Specifications
Electrical Specifications
Performance Specifications
High accuracy magnetic calibration
RS232/485/TTL optional
50Hz
<3s
100g
Package size: L107 x W38 x H25 (mm)
Bare size：L75 x W30.5 x H10 (mm)
Yes
Yes
Yes
0.01°
0.1°
0.1°
0.05°
0.01°
2400-115200 Baud rate
2000g
±45°
＜0.5 RMS（Pitch<30°）
0.2 RMS（Horizontal use）
Yes
Hard magnetic calibration
Soft magnetic calibration
Limited tilt user calibration
Size
Weight
Start delay
Frequency response
RS-232Communication rate
Anti-vibration performance
Output form
Resolution
Repeatability
Pitch accuracy
Roll accuracy
Resolution
Tilt range
Heading accuracy
Bewis Sensing Technology LLC www.bwsensing.com Tel：[phone]

BMR3300
Three-Axis Accelerometer Three-Axis Magnetometer
High Accuracy Electronic Compass
Resolution: The measured minimum change value that the sensor can detect and resolve within
the measurement range.
Accuracy: The error between the actual angle and the Root mean square(RMS) of the measured
angle of the sensor (≥16 times).
Mechanical Characteristic
Connector
Installation
Cable socket(30cm cable)
Four M2 screws
Bare plate product size
Product size: L75 x W30.5 x H10 (mm)
Note: ±1mm error for length and width dimensions, please refer to actual.
holeΦ 2.1
Bewis Sensing Technology LLC www.bwsensing.com Tel：[phone]

BMR3300
Three-Axis Accelerometer Three-Axis Magnetometer
High Accuracy Electronic Compass
Calibration
Method 1 - Plane calibration:
1.Fix the electronic compass in the use environment, and try not to carry magnetic items such as keys
and mobile phones during calibration;
2.Connect the product to the system and put it in a horizontal state(within ±5°);
3.Open the serial debugging assistant and send the start calibration command in hexadecimal format:
77 04 00 11 15;
4.Rotate the product 2-3 turns around the z-axis (the vertical direction of the z-axis) in the horizontal
plane (with the pitch angle and roll angle within ±5°). The rotation process should be as slow as
possible and rotate at a uniform speed. The time of one rotation is about 10~15 seconds;
5.Rotate the product about 2-3 turns around the X-axis or Y-axis. The rotation process should be as
slow as possible and rotate at a uniform speed. The time of one rotation is about 10~15 seconds.
6.Complete the calibration and send the save calibration command: 77 04 00 12 16.
The main sensitive components of the BMR3300 sensor are magnetometers and accelerometers.
The compass uses a magnetometer to sense the geomagnetic field to calculate the direction of the
sensor. The accelerometer is used to measure the angle between the compass and the gravity, and
provides the tilt compensation when the compass calculates the azimuth. The earth's magnetic
field is easily interfered by the external magnetic field. Users should pay attention to the surrounding
magnetic field during installation to ensure that the sensor is exposed to the earth's magnetic field
and avoid using it near ferromagnetic materials and changing magnetic fields, Such as engines,
iron plates, iron bolts and nuts, wires, motors, speakers, antennas, etc. It is important to strictly avoid
magnets, motors and other strong magnetic substances within 10cm of the compass, which may
cause the measurement accuracy of the compass to irreversibly decrease. We strongly recommend
magnetic field calibration after installation and every time the magnetic field environment
changes. After the calibration in accordance with the manual, the firmware and program in the
BMR3300 can effectively eliminate the interference of the magnetic field. As long as the position
of the compass and the surrounding magnetic field environment have not changed, it is no longer
necessary to compensate the sensor.
Tests have shown that if the user performs the calibration operation according to the requirements of
the user manual so that the compass can meet the above requirements during installation and
correctly calibrate the sensor, the heading accuracy of the sensor will be less than 0.5 degrees (RMS).
The recommended test method is to mount the BMR3300 sensor horizontally on a non-
magnetic material away from interference for heading angle measurement. Avoid extra
magnetic field interference during measurement.
Measurement & Installation
The electronic compass has been calibrated at the factory. In places where the influence of the
magnetic field environment is small, it is not necessary to perform environmental calibration and can
be used directly. During actual use, it is recommended to perform calibration.
Azimuth calibration step:
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High-precision magnetometer calibration is suitable for products that have already been packaged,
and other methods are used for bare boards.
1.Fix the electronic compass in the use environment, and try not to carry magnetic items such as keys
and mobile phones during calibration;
2.Connect the product to the system and put it in a horizontal state(within ±5°);
3.Open the serial debugging assistant and send the start calibration command in hexadecimal format:
77 04 00 08 0C.The rotation process should be as slow as possible and rotate at a uniform speed. The
time of one rotation is about 10~15 seconds;
4.Starting from 0 degrees defined by yourself, the acquisition command is sent every 30 degrees,
waiting to receive the return command and then continuing to rotate until the product rotates
around the Z axis for a total of 13 points.
[Acquisition command: 77 04 00 A1 A5, return command: 77 05 00 A1 XX YY, XX is the hexadecimal
number corresponding to the collection point, and the return value corresponding to the last point is
0D.]
5.Send end calibration command: 77 04 00 A2 A6, received return value: 77 05 00 A2 00 A7.
6.Wait for about 20~30s until the sensor returns to the end command: 77 05 00 A2 01 A8, the
calibration is completed.
无锡北微传感科技有限公司
www.bwsensing.com Tel: [phone]
BMR3300
Three-Axis Accelerometer Three-Axis Magnetometer
High Accuracy Electronic Compass
Method 2 - Multi-face calibration:
1.Fix the electronic compass in the use environment, and try not to carry magnetic items such as keys
and mobile phones during calibration;
2.Connect the product to the system and put it in a horizontal state(within ±5°);
3.Open the serial debugging assistant and send the start calibration command in hexadecimal format:
77 04 00 08 0C, return value 77 05 00 88 00 8D;
4.The product is placed horizontally, face up (pitch and roll are within ±5°), rotate one revolution at a
constant speed approximately and use for more than 10 seconds.
5.The product is placed horizontally, with the mounting surface facing up (pitch and roll are within ±5°),
rotate one revolution at a constant speed approximately and use for more than 10 seconds.
6.The product is placed in a vertical state, the smooth side of the casing is facing downward (the pitch
and the roll are both within ±5°), rotate one revolution at a constant speed approximately and use for
more than 10 seconds.
7.The product is placed in a vertical state, and the other smooth side of the casing faces downward
(the pitch and the roll are both within ±5°), rotate one revolution at a constant speed approximately
and use for more than 10 seconds.
[Where step 4.5.6.7 can be exchanged];
8.After the four faces have been rotated, send the hexadecimal command 77 04 00 09 0D to save the
calibration and return to 77 05 00 89 XX YY. (XX represents the calibration error coefficient, the
smaller the value, the better, less than 1 is ideal, FF indicates calibration failure, and YY is the
checksum of the command);
9.Calibration completed
Method 3 - High-accuracy magnetometer calibration＞
Note: Do not power off or send other commands before receiving the end command to prevent the
sensor from losing data.
Bewis Sensing Technology LLC www.bwsensing.com Tel：[phone]

BMR3300
Three-Axis Accelerometer Three-Axis Magnetometer
High Accuracy Electronic Compass
1
3
4
5
GND
DC 9-35V
1
5
4
2
3
6
7
8
9
BLACK GND
YELLOW TXD
RED VCC
GREEN RXD
Electrical interfaces
RED
1
VCC
DC 9-35V
BLUE
2
NC
BLACK
3
GND
GREEN
4
RXD
（B、D-）
YELLOW
5
TXD
（A、D+）
Sensor
1
3
7
RED VCC DC 9-35V
485A/485+
485B/485-
GND
Electronic
compass
1
3
4
5
GREEN
Electrical connectionss
Cable color
&
function
YELLOW
33
44
55
88
99
Signal 66
22
acquisition
end
BLACK GND
RS 485 wiring diagram
Electronic
compass
RS 232 wiring diagram
Bewis Sensing Technology LLC www.bwsensing.com Tel：[phone]

BMR3300
Three-Axis Accelerometer Three-Axis Magnetometer
High Accuracy Electronic Compass
2.1 Read PITCH angle Command：77 04 00 01 05
2.2 Read ROLL angle Command： 77 04 00 02 06
Protocol
1Data Frame Format： （8 data bits，1 stop bit，No parity check，default baud rate 9600）
Identifier
（1byte
0x77
Frame Length
（1byte）
Address Code
（1byte）
Command
（1byte）
Data Checksum
（1byte）
（Xbyte）
Data Format: Hexadecimal
Identifier: Fixed to 77
Frame Length: Length from Frame Length to Checksum（included）
Address Code: Address of acquiring module, default 0x00
Data: Content and length variable according to Command
Checksum: Sum of Frame Length, Address Code, Command and Data. (Please pay attention
that when the command or data changes, the checksum will change. )
2 Command Format:
0x77 0x01
Command response：
0x77 0x81 SXXX.YY
0x07
Identifier
（1byte Frame Length
（1byte）
Address Code
（1byte）
Command
（1byte）
Data
（0byte） Checksum
（1byte）
Identifier
（1byte Frame Length
（1byte）
Address Code
（1byte）
Command
（1byte）
Data
（3byte） Checksum
（1byte）
Note: Data represents 4 byte angle value in format of compressed BCD code. S is the sign bit (0 means positive,
1 means negative), XXX is the three digit integer part, YY is the fractional part. The Data of other axis is the same
format. For example, 10 26 87 means -026.87 °.
0x04 0x05
0x77 0x02
Command response：
0x77 0x82 SXXX.YY
0x07
Identifier
（1byte Frame Length
（1byte）
Address Code
（1byte）
Command
（1byte）
Data
（0byte） Checksum
（1byte）
Identifier
（1byte Frame Length
（1byte）
Address Code
（1byte）
Command
（1byte）
Data
（3byte） Checksum
（1byte）
0x04 0x06
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Bewis Sensing Technology LLC www.bwsensing.com Tel：[phone]

BMR3300
Three-Axis Accelerometer Three-Axis Magnetometer
High Accuracy Electronic Compass
2.3 Read Heading azimuth angle Command： 77 04 00 03 07
2.4 Read PITCH,ROLL,HEADING axis angle Command： 77 04 00 04 08
Identifier;
fixed as 77
Frame Length The
length of all bytes
exclude identifier
00 device address;
00 by default
Command code，0X84
means return simultaneously
Pitch，Roll，heading
Angel of Roll，33.65°
Angel of Heading，313.71°
Checksum
Angle of Pitch, format is SXXX.YY. S is the sign bit
( 0 means positive, 1 means negative), XX are the
digit integer part, YY are the fractional part . The
data of other axis is the same format. For example,
10 27 70 means -26.70 ° .
Note: The data field contains 9 bytes of Pitch, Roll and Heading angle values, which are compressed BCD codes,
each of which is a group of three bytes. For example, the return command is 77 0D 00. 84 10 26 80 00 33 65 03
13 71 66, where Pitch is 10 26 80, Roll is 00 33 65, Heading is 03 13 71. For the three bytes of the return value for
each angle, the format is SX XX YY, S is the sign bit (0 positive, 1 negative) XXX is a three-digit integer value, and
YY is a decimal value. The corresponding three angle readings for this example are: -26.8°, 33.65°, 313.71°.
77 0D 00 84 10 26 80 00 33 65 03 13 71 66
0x77 0x03
Command response：
0x77 0x83SXXX.YY
0x07
Identifier
（1byte Frame Length
（1byte）
Address Code
（1byte）
Command
（1byte）
Data
（0byte） Checksum
（1byte）
Identifier
（1byte Frame Length
（1byte）
Address Code
（1byte）
Command
（1byte）
Data
（3byte） Checksum
（1byte）
0x04
0x77 0x04
Command response：
0x77 0x84 *
0x07
Identifier
（1byte Frame Length
（1byte）
Address Code
（1byte）
Command
（1byte）
Data
（0byte） Checksum
（1byte）
Identifier
（1byte Frame Length
（1byte）
Address Code
（1byte）
Command
（1byte）
Data
（9byte） Checksum
（1byte）
0x04
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Note: The format of the SX XY is the same as the format of the magnetic declination to be set in the 2.5 command.
BMR3300
Three-Axis Accelerometer Three-Axis Magnetometer
High Accuracy Electronic Compass
2.5 Set the magnetic declination Command： 77 06 00 06 02 08 16
0x77 0x06
Command response：
0x77 0x86
SXXX.YY
0x05
Identifier
（1byte
Frame Length
（1byte）
Address Code
（1byte）
Command
（1byte）
Data
（2byte） Checksum
（1byte）
Identifier
（1byte
Frame Length
（1byte）
Address Code
（1byte）
Command
（1byte）
Data
（1byte）
Checksum
（1byte）
0x060x06
0x00: success
0xFF: failure
Note: S indicates a symbol, 0 is positive 1 is negative, XX is a two-digit integer, and Y is 1 decimal. For example, 02
08 is +20.8°. The checksum of the command is 16 (hex).16 = 06+00+06+02+08. If the declination is set to -3.2°,
the command is 77 06 00 06 10 32 4E, where 4E = 06+00+06+10+32. Other magnetic declinations are analogous.
2.6 Read magnetic declination Command： 77 04 00 07 0B
Command response：
0x87
0x77 0x07
00xx7777
Identifier
（1byte
Frame Length
（1byte）
Address Code
（1byte）
Command
（1byte）
Data
（0byte） Checksum
（1byte）
Identifier
（1byte
Frame Length
（1byte）
Address Code
（1byte）
Command
（1byte）
Data
（2byte） Checksum
（1byte）
0x04
0x05SXXY
2.7 Set baud rate
Note: 00:2400,01:4800,02:9600,03:19200,04:115200,05:38400,6:57600. If the baud rate is set to 19200, the
command is 77 05 00 0B 03 13, where 13 = 05+ 00+ 0B+ 03, and so on when setting other baud rates.
Note: After setting the baud rate, the device will return the response command at the original baud rate. After
that, the baud rate setting will take effect and the host computer needs to make the corresponding baud rate
change to re-communicate with the device.
Command： 77 05 00 0B 02 12
0x77 0x0B
Command response：
0x77 0x05
Identifier
（1byte
Frame Length
（1byte）
Address Code
（1byte）
Command
（1byte）
Data
（1byte） Checksum
（1byte）
Identifier
（1byte
Frame Length
（1byte）
Address Code
（1byte）
Command
（1byte）
Data
（1byte）
Checksum
（1byte）
0x05
0x00: success
0xFF: failure
Bewis Sensing Technology LLC www.bwsensing.com Tel：[phone]

BMR3300
Three-Axis Accelerometer Three-Axis Magnetometer
High Accuracy Electronic Compass
Note: The default address of the sensor is 0x00. When the query address command is sent, the returned data
field is the hexadecimal device address.
2.10 Set output mode Command：77 05 00 0C 00 11
0x77 0x0C
0x00: question and answer Mode
0x01: 5Hz Data Rate
0x02: 10Hz Data Rate
0x03: 20Hz Data Rate
0x04: 25Hz Data Rate
0x05: 50Hz Data Rate
0x06: 100Hz Data Rate
（1byte
Frame Length
（1byte）
Address Code
（1byte）
Command
（1byte） Data
（1byte） Checksum
（1byte）
Identifier
Note: The default output mode is 00(when setting 100HZ output frequency.
Set baud rate to 115200 in high speed mode.
0x05
Command response：
0x1F
0x77 0x1F
2.9 Query address Command：77 04 00 1F 23
00xx7777
Identifier
（1byte
Frame Length
（1byte）
Address Code
（1byte）
Command
（1byte）
Data
（0byte） Checksum
（1byte）
Identifier
（1byte
Frame Length
（1byte）
Address Code
（1byte）
Command
（1byte）
Data
（1byte） Checksum
（1byte）
0x04
0x05
0x77
Command response：
2.8 Set address Command: 77 05 00 0F 01 15
0x0F
0x77 0x8F0x00: success
0xFF: failure
XX Address
Identifier
（1byte
Frame Length
（1byte） Address Code
（1byte）
Command
（1byte） Data
（1byte）
Checksum
（1byte）
Identifier
（1byte
Frame Length
（1byte）
Address Code
（1byte）
Command
（1byte） Data
（1byte）
Checksum
（1byte）
0x05
0x05
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2.12 Switch calibration output Command: 77 04 00 A3 A7
BMR3300
Three-Axis Accelerometer Three-Axis Magnetometer
High Accuracy Electronic Compass
Note: 5Hz Data Rate means that 5 sets of angle data are automatically output every second, and so on.
When the product with the half-duplex RS485 interface is set to automatically outputs data to the outside, it
may not be able to receive the input command effectively. At this point you may need to repeatedly send the
command so that product can receive it. Therefore, if you need to send commands to interact with the product,
it is recommended to set the product to work in Q&A mode. In addition, when the product is set to the
automatic output mode, there will be no output within 10 seconds after the product is powered on, and the
product can effectively receive the external setting command.
0x77 0x8C 0x00: success
0xFF: failure
0x05
Identifier
（1byte
Frame Length
（1byte）
Address Code
（1byte）
Command
（1byte）
Data
（1byte） Checksum
（1byte）
Command response：
Command response：
2.11 Save setting Command：77 04 00 0A 0E
0x77
Note: If Save setting command is not executed, all setting will be invalid after power off.
0x00: success
0xFF: failure
0x77 0x0A
0x8A
0x05
Identifier
（1byte Frame Length
（1byte）
Address Code
（1byte） Command
（1byte）
Data
（0 byte） Checksum
（1byte）
Identifier
（1byte
Frame Length
（1byte）
Address Code
（1byte） Command
（1byte）
Data
（1byte）
Checksum
（1byte）
0x04
Command response：
0x77 0x00: (close)
0x01: (open)
0x77 0xA3
0xA3
0x05
Identifier
（1byte Frame Length
（1byte）
Address Code
（1byte） Command
（1byte）
Data
（0 byte） Checksum
（1byte）
Identifier
（1byte
Frame Length
（1byte）
Address Code
（1byte） Command
（1byte）
Data
（1byte）
Checksum
（1byte）
0x04
0x00
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Product number Package condition
BMR3300-232
BMR3300-485
BMR3300-TTL
Bare board
Way of communication
R 232
RS485
TTL
S
BMR3300
Three-Axis Accelerometer Three-Axis Magnetometer
High Accuracy Electronic Compass
Bare board
Bare board
Ordering Information
Executive standard
●Enterprise Quality System Standard: ISO9001:2008 Standard (Certificate No.:10114Q16846ROS)
●CE certification (certificate number: 3854210814)
●ROHS (certificate number: SO81426003)
●GB/T 191 SJ 20873-2003 General specifications for tiltmeters and spirit levels
●GBT 18459-2001 sensor main static performance index calculation method
●JF 1059-1999 Evaluation and Expression of Measurement Uncertainty
●GBT 14412-2005 mechanical vibration and shock mechanical installation of accelerometer
●General requirements for GJB 450A-2004 equipment reliability
●Quality control of key parts and important parts of GJB 909A
●GJB 899 Reliability Qualification and Acceptance Test
●GJB 150-3A high temperature test
●GJB 150-4A low temperature test
●GJB 150-8A rain test
●GJB 150-12A dust test
●GJB 150-16A vibration test
●GJB 150-18A impact test
●GJB 150-23A Tilt and Swing Test
●GB/T 17626-3A RF electromagnetic radiation immunity test
●GB/T 17626-5A surge (hit) impulse immunity test
●GB/T 17626-8A power frequency magnetic field immunity test
●GB/T 17626-11A voltage dips, short interruptions and voltage changes immunity
Bewis Sensing Technology LLC www.bwsensing.com Tel：[phone]

BMR3300
Three-Axis Accelerometer
Three-Axis Magnetometer
High Accuracy Electronic Compass
Wuxi Bewis Sensing Technology LLC
Address: Building 30, No. 58 Xiuxi Road, Binhu District, Wuxi City
Hotline: [phone]
Tel: [phone]-801
Email: [email protected]
Website: www.bwsensing.com