BW SENSING LEC315 Series User manual

LEC315 Serials
Inclination Compensation
3D Electronic Compass
Technical Manual

LEC315 is a cost-effective 3D electronic compass developed by Bewis Sensing Technology LLC.
The product adopts the patented hard iron and soft iron calibration algorithm of Beiwei
Sensing Technology LLC, which can provide high-precision heading information when its inclination
reaches 30°. It has the advantages of small size and low power consumption, and is suitable for
sensitive measurement systems with mini and high precision.
The LEC315 integrates a three-axis magnetic sensor that compensates for the tilt angle with a three-
axis accelerometer when the heading is solved in real time by the central processor, providing
accurate heading data in very harsh environments. The LEC315 supports RS232, RS485 and TTL level
output interfaces. The output baud rate is 2400-115200, and the output angle is 0°~360°. There
are two types--hexadecimal and Modbus protocols for optional. It can be adapted to
different application scenarios and can integrate the electronic compass function into various
systems very conveniently and quickly.
●Accuracy: 2° (RMS)
●Operating temperature: -40 ° C ~ +85 ° C
●Small size: L55 x W37 x H24(mm)
●Supply voltage: 5V
●Hard magnetic, soft magnetic and
inclination compensation
●Resolution: 0.1°
●Rolling pitch accuracy: 0.2°
●RS232/RS485/TTL interface optional
LEC315
Inclination compensation 3D
electronic compass
●Satellite tracking
●Petroleum geological exploration
●Optical range finder
●GPS-assisted navigation
●Individual combat equipment
●Ocean test
●Underwater navigation
●Mechanical control
/TZXUJ[IZOUT
,KGZ[XKY
'VVROIGZOUTY
Bewis Sensing Technology LLC www.bwsensing.com Tel：[phone]

Power supply
Operating current
Operating temperature
Store temperature
+5V DC
30mA（Max40mA）
-40~85℃
-55~100℃
Compass heading
parameter
Compass tilt
parameter
Calibration
Physical
specifications
Interface
specifications
Environment
LEC315
Inclination compensation 3D
electronic compass
Specifications
Electrical Specifications
Performance Specifications
Heading accuracy
Resolution
Repeatability
Dip resolution
Hard magnetic calibration
Soft magnetic calibration
Tilt calibration
Size
Weight
Start delay
Frequency response
RS-232Communication rate
Tilt range
Pitch accuracy
Rolling accuracy
Output form
Anti-vibration performance
RS232/485/TTL Optional
50Hz
<3s
115g
L55 x W37 x H24 (mm)
Yes
Yes
Yes
0.01°
0.5°
0.1°
2°（RMS，Pitch <85°）
2400-115200 Baud rate
±30°
0.15°
0.15°
2000g
Bewis Sensing Technology LLC www.bwsensing.com Tel：[phone]

LEC315
Inclination compensation 3D
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
Package size
Product Size: L55*W37*H24(mm)
Connector
Protection level
Shell material
Installation
Metal connector（standard cable is 1.5m）
IP67
Magnesium alloy anodizing
Four M4 screws
55
48
29
37
4
11 24
4 HOLE
Bewis Sensing Technology LLC www.bwsensing.com Tel：[phone]

Calibration
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.
Method 1 - Plane calibration:
1.Connect the product to the system and place the product in a horizontal state;
2.Open the serial port debugging assistant and send 77 04 00 11 15;
3.Rotate the product in the horizontal plane (with the pitch and roll angles within ±5°) around the z-
axis (z-axis is vertical) and rotate 2-3 turns. The rotation process is as slow as possible and rotates at a
constant speed. The time of one rotation is controlled between 10 seconds and 15 seconds;
4.Rotating the compass around the X-axis or the Y-axis, the rotation process is as slow as possible and
rotates at a constant speed, rotating 2-3 turns around each axis, and the time of one rotation is about
15 seconds;
5.Complete calibration, send 77 04 00 12 16 to save calibration.
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.Place the compass in a horizontal state (within ±5°);
3.Send the following 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.
The main sensitive components of the LEC315 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
LEC315 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 2 degrees (RMS).
The recommended test method is to mount the LEC315 sensor horizontally on a non-
magnetic material away from interference for heading angle measurement. Avoid extra
magnetic field interference during measurement.
LEC315
Inclination compensation 3D
electronic compass
Measurement & Installation
Azimuth calibration step:
Bewis Sensing Technology LLC www.bwsensing.com Tel：[phone]

1
3
4
5
GND
DC 5V
1
5
4
2
3
6
7
8
9
BLACK GND
YELLOW TXD
RED VCC
GREEN RXD
Electrical interfaces
RED
1
VCC
DC 5V
BLUE
2
NC
BLACK
3
GND
GREEN
4
RXD
（B、D-）
YELLOW
5
TXD
（A、D+）
Sensor
1
3
7
RED VCC DC 5V
485A/485+
485B/485-
BLACK GND GND
Electronic
compass
1
3
4
5
GREEN
LEC315
Inclination compensation 3D
electronic compass
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
Electrical connectionss
Cable color
&
function
YELLOW
33
44
55
88
99
Signal 66
22
acquisition
end
RS 485 wiring diagram
Electronic
compass
RS 232 wiring diagram
Bewis Sensing Technology LLC www.bwsensing.com Tel：[phone]

2.1 Read PITCH angle Command：77 04 00 01 05
2.2 Read ROLL angle Command： 77 04 00 02 06
LEC315
Inclination compensation 3D
electronic compass
Protocol
1Data Frame Format：
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. )
（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）
（0byte）
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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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
LEC315
Inclination compensation 3D
electronic compass
0x77 0x03
Command response：
0x77 0x83 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
0x77 0x04
Command response：
0x77 0x84 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
（9byte） Checksum
（1byte）
0x04 0x06
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2.5 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.
2.6 Set the magnetic declination Command： 77 06 00 06 02 08 16
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.
2.7 Read magnetic declination Command： 77 04 00 07 0B
LEC315
Inclination compensation 3D
electronic compass
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
0x06 SXXY
Command： 77 05 00 0B 02 12
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）
0x06 0x06
0x00: success
0xFF: failure
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
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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.
LEC315
Inclination compensation 3D
electronic compass
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 0x8F 0x00: 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
Bewis Sensing Technology LLC www.bwsensing.com Tel：[phone]

LEC315
Inclination compensation 3D
electronic compass
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
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
Note: 5Hz Data Rate means that 5 sets of angle data are automatically output every second, and so on.
0x8C 0x00: success
0xFF: failure
0x05
Identifier
（1byte
Frame Length
（1byte）
Address Code
（1byte）
Command
（1byte）
Data
（1byte） Checksum
（1byte）
Command response：
Bewis Sensing Technology LLC www.bwsensing.com Tel：[phone]

LEC315
Inclination compensation 3D
electronic compass
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
Ordering Information
Product number Package condition
IP67 Package/Metal Connector
IP67 Package/Metal Connector
IP67 Package/Metal Connector
Way of communication
LEC315-232
LEC315-485
LEC315-TTL
R 2
S
32
RS485
TTL
Bewis Sensing Technology LLC www.bwsensing.com Tel：[phone]

L
Inclination compensa
EC315
tion
3D 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