BW SENSING BWM826 User manual

BWM826
*igital Dual-Axis Inclinometer
Technical Manual

BWM 826
Digital Dual-Axis Inclinometer
●Dual-axis inclination measurement
●Measuring range: ±30°
●Max accuracy: 0.005°
●Voltage input: 9~35V
●Output mode: RS485/RS232/TTL optional
●Operating temperature: -40℃~+85℃
●IP67 protection
●High vibration resistance>2000g
●High resolution: 0.001°
●Product size: L90*W40.5*H26（mm）
●Dangerous building monitoring
●Bridge monitoring
●Satellite antenna positioning
●Laser level
●Slope monitoring
●High-speed rail monitoring
●Piling monitoring
●Ancient building protection monitoring
Introduction
Features
Applications
Designed by Bewis Sensing Technology LLC, BWM826 is a cost-effective dual-axis inclinometer with MEMS
technology and digital output. It has a measuring range of ± 30° and a full-scale accuracy of 0.005° and a
operating temperature of -40℃~+85℃. The product uses a high-accuracy MEMS accelerometer and a high-
resolution differential digital-to-analog converter with built-in automatic compensation and filtering
algorithms to reduce errors caused by environmental changes. It measures the change of static gravitational
field and converts it into angle change. The change directly outputs the horizontal angle value through
digital mode. It has high long-term stability, small temperature drift, simple use and strong resistance to
external interference. It apply to military equipment, industrial automation, surveying and mapping, etc.
Bewis Sensing Technology LLC
www.bwsensing.com Tel: [phone]

2000g, 0.5ms, 3 times/axis
150(package excluded)
Conditions
Indoor
-40～85℃
25℃
BWM826-5
±5
X-Y
0.005
0.001
±0.001
0.005
100
BWM826-15
±15
X-Y
0.008
0.001
±0.001
0.008
100
according to GBT17626
≥100 MΩ
≥90000 hours/time
BWM826-30
±30
X-Y
0.01
0.001
±0.001
0.01
100
°
°
°/℃
Hz
Units
°
°
BWM 826
Digital Dual-Axis Inclinometer
Parameters
Power supply
Operating current
Operating temperature
Store temperature
Conditions
Non-loaded
Min
9
20
-40
-55
Typical
12
30
Max
35
40
+85
+100
Units
V
mA
℃
℃
Specifications
Electrical Specifications
25
25
Performance Specifications
Measuring range
Measuring axis
Accuracy
Resolution
Frequency response
Electromagnetic
compatibility
Insulation resistance
Shock resistance
Weight（g）
Zero temperature
drift
MTBF
Cross axis error
Parameters
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).
Bewis Sensing Technology LLC
www.bwsensing.com Tel: [phone]

90
78
29
40.5
4
11 26
4.5 hole
11
BWM 826
Digital Dual-Axis Inclinometer
Package size
Product Size: L90*W40.5*H26(mm)
Mechanical Characteristic
Connector
Protection level
Shell material
Installation
Metal connector（standard cable is 1.5m）
IP67
Magnesium alloy anodizing
Four M4 screws
Bewis Sensing Technology LLC
www.bwsensing.com Tel: [phone]
Hole Φ 2.1mm
3030
4141
4747
3636
Bare plate product size
Product size: L47*W36*H15(mm)
Note: ±1mm error for length and width dimensions, please refer to actual size.
RS232 output RS485/TTL output

BWM 826
Digital Dual-Axis Inclinometer
Installation direction
The correct installation method can avoid measurement error. The following points should be made
when installing the sensor:
First of all, to ensure that the sensor mounting surface and the measured surface completely close,
the measured surface should be as horizontal as possible, can not have the angle shown in Figure A
and Figure C, the correct installation is shown in Figure B and Figure D.
the measured surface
uneven surface
generates the
angle
the measured surface
C D
AB
the measured surface the measured surface
Secondly, the bottom cable of the sensor and the axis of the measured object shouldn't generate
the angle shown in E. When installing, the bottom cable of the sensor should be kept parallel or
orthogonal to the rotation axis of the measured object. This product can be installed horizontally
or vertically (vertical installation requires customization). The correct installation method is shown in
Figure F.
Finally, the installation surface of the sensor must be fixed with the measured surface tightly and
smoothly, to avoid measurement error that may be caused by the acceleration and vibration.
uneven surface
generates the
angle
Bewis Sensing Technology LLC
www.bwsensing.com Tel: [phone]

RS 485 Electrical interfaces
RED
1
VCC
DC 9-35V
BLUE
2
NC
BLACK
3
GND地
GREEN
4
B
485-
YELLOW
5
A
485+
1
5
4
3
Sensor
POWER+ POWER-
YELLOW: TXD
DC 9-35V
GREEN: RXD
BLACK: GND
12
3
4
5
67
485+
485-
Signal
acquisition
end
12.00V12.00V
POWER
9~35V
BWM 826
Digital Dual-Axis Inclinometer
Electrical connections
Cable color
&
Function
Bewis Sensing Technology LLC
www.bwsensing.com Tel: [phone]
RS232 Electrical interfaces
RED
1
VCC
DC 9-35V
BLUE
2
NC
BLACK
3
GND
GREEN
4
RXD
YELLOW
5
TXD
Cable color
&
Function
1
5
4
3
Sensor
POWER+ POWER-
YELLOW: TXD
RED DC 9-35V 1
6
7
8
9
3
2
4
5
POWER
GREEN: RXD
BLACK: GND
9~35V
12
3
4
5
67

BWM 826
Digital Dual-Axis Inclinometer
Debug software
Users can directly download serial assistant on official website (Supports-Download). You can also use
more convenient and intuitive PC software.
BWM826 supporting serial debugging software can be connected to the inclinometer on the computer
for angle display. The software debugging interface is as shown in the figure below. Using the debug
software, it can conveniently display the current X-direction tilt angle, and you can also modify and
set other parameters by yourself.
①
②
③
Correctly connect the inclinometer serial port hardware and connect the power supply.
Select the computer serial port and baud rate and click connect Serial Port.
Click Start and the tilt angle of the X, Y Axis will be displayed on the screen.
Software use steps:
Bewis Sensing Technology LLC
www.bwsensing.com Tel: [phone]

BWM 826
Digital Dual-Axis Inclinometer
(nbyte)
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
（2byte） Command
（1byte） Data Checksum
（1byte）
2 Command Format
2.1 Read angle of X axis Command：77 05 00 00 01 06
0x77 0x01
Command response：
0x77 0x81
Note: The data field is a 4-byte return angle value, which is a compressed BCD code, S is a sign bit (0 positive, 1
negative), XXX is a three-digit integer value, and YYY is a decimal value. The Data of other axis is the same
format. For example, 10 26 80 70 means -026.8070 °.
0x07
Frame Length
（1byte）
Address Code
（2byte） Command
（1byte）
Data
（0byte） Checksum
（1byte）
Frame Length
（1byte）
Address Code
（2byte） Command
（1byte）
Data
（4byte） Checksum
（1byte）
2.2 Read angle of Y axis Command：77 05 00 00 02 07
0x77 0x02
Command response：
0x77 0x82
Frame Length
（1byte）
Address Code
（2byte） Command
（1byte）
Data
（0byte） Checksum
（1byte）
Frame Length
（1byte）
Address Code
（2byte） Command
（1byte）
Data
（4byte） Checksum
（1byte）
SXXX.YYY0
SXXX.YYY0
Identifier
（1byte）
Identifier
（1byte）
Identifier
（1byte）
Identifier
（1byte）
Bewis Sensing Technology LLC
www.bwsensing.com Tel: [phone]

2.5 Set baud rate Command：77 06 00 00 0B 04 15
Note: 00:2400 01 :4800 02:9600 03:19200 04:115200, the default is 9600
Each time the communication baud rate is changed successfully, the response command is sent back at the
original baud rate, and then the device communication baud rate is changed immediately.
Note: If high frequency output is required, set the baud rate to 115200.
BWM 826
Digital Dual-Axis Inclinometer
2.3 Read angle of X,Y axis Command：77 05 00 00 04 09
0x77 0x04
Command response：
0x77 0x84
Frame Length
（1byte）
Address Code
（2byte） Command
（1byte）
Data
（0byte） Checksum
（1byte）
Frame Length
（1byte）
Address Code
（2byte） Command
（1byte）
Data
（12byte） Checksum
（1byte）
Note: The data field is a 12-byte return angle value, divided into three groups, each group of four compressed
BCD codes. They are the X-axis angle, the Y-axis angle, and the Z-axis (all 0). Each axis data format SXXX.YYY0, S is
a sign bit (0 positive, 1 negative) XXX is a three-digit integer value, YYY is a three-digit decimal value. The other
axis data is the same. For example, 10 26 87 60 means -026.8760°.
Such as: 77 11 00 00 84 00 02 01 30 10 00 51 20 00 00 00 00 49
Where 00 02 01 30 represents the X-axis angle of +2.013°, and 10 00 51 20 represents the Y-axis angle of -0.512°.
2.4 Set absolute/relative zero point Command：77 06 00 00 05 01 0C
Command response：
Note: absolute zero：Based on the factory-calibrated zero point.
relative zero: Reference to the zero after the current installation.
0x77 0x85 0x00: success
0xFF: failure
0x77 0x05
0x00: absolute zero
0x01: relative zero
Frame Length
（1byte） Address Code
（2byte） Command
（1byte）
Data
（1byte）
Checksum
（1byte）
Frame Length
（1byte）
Address Code
（2byte） Command
（1byte）
Data
（1byte）
Checksum
（1byte）
Command response：
0x77 0x8B 0x00: success
0xFF: failure
Frame Length
（1byte）
Address Code
（2byte） Command
（1byte）
Data
（1byte）
Checksum
（1byte）
0x77 0x0B
Frame Length
（1byte）
Address Code
（2byte） Command
（1byte）
Data
（1byte） Checksum
（1byte）
0x00
Identifier
（1byte）
Identifier
（1byte）
Identifier
（1byte）
Identifier
（1byte）
Identifier
（1byte）
Identifier
（1byte）
Bewis Sensing Technology LLC
www.bwsensing.com Tel: [phone]

Note: This command refers to whether the zero point reference used in the current state is relative zero or
absolute zero;
BWM 826
Digital Dual-Axis Inclinometer
Command response：
2.6 Save setting Command：77 05 00 00 0A 0F
0x77
Note: If Save setting command is not executed, all setting will be invalid after power off.
0x00: success
0xFF: failure
0x77 0x0A
0x8A
Frame Length
（1byte）
Address Code
（2byte） Command
（1byte）
Data
（1byte） Checksum
（1byte）
Frame Length
（1byte）
Address Code
（2byte） Command
（1byte）
Data
（1byte）
Checksum
（1byte）
Command response：
0x1F
0x77 0x1F
2.7 Query address Command：77 05 00 00 1F 24
Frame Length
（1byte）
Address Code
（2byte） Command
（1byte）
Data
（0byte） Checksum
（1byte）
Frame Length
（1byte）
Address Code
（2byte） Command
（1byte）
Data
（2byte）
Checksum
（1byte）
0x05
0x77
00x00
0x77
Command response：
2.8 Query relative / absolute zero Command：77 05 00 00 0D 12
0x0D
Frame Length
（1byte） Address Code
（2byte） Command
（1byte）
Data
（0byte）
Checksum
（1byte）
0x77 0x8D
0x00: absolute zero
0xFF: relative zero
Frame Length
（1byte） Address Code
（2byte） Command
（1byte）
Data
（1byte）
Checksum
（1byte）
Identifier
（1byte）
Identifier
（1byte）
Identifier
（1byte）
Identifier
（1byte）
Identifier
（1byte）
Identifier
（1byte）
Bewis Sensing Technology LLC
www.bwsensing.com Tel: [phone]