Rion HCM370B User manual

HCM370B&375B-MP HIGH ACCURACY 3D DIGITAL COMPASS
○Inclinometer ○3D compass ○Digital inclinometer ○Accelerometer ○Gyro ○North finder ○INS&IMU
SINCE2008 ·Inertial Attitude Measurement Manufacturer
V1.1
RION HCM370B/HCM375B-MP
HIGH ACCURACY 3D DIGITAL COMPASS
Technical Manual
Patent No.: ZL201730609573.9

HCM370B&375B-MP HIGH ACCURACY 3D DIGITAL COMPASS
○Inclinometer ○3D compass ○Digital inclinometer ○Accelerometer ○Gyro ○North finder ○INS&IMU
SINCE2008 ·Inertial Attitude Measurement Manufacturer
RION QUALIFICATION CERTIFICATION
○Enterprise quality system standard: ISO9001:2015 standard (Certification No.: 128101)
○High-tech Enterprise (Certificate No.: GR201844204379)
○China National Intellectual Property Appearance Patent (Patent No.: ZL 201730609573.9)
○Revision time: 2021-6-3
○Product functions, parameters, appearance, etc. will be adjusted as technology upgrades. Please
contact our pre-sales business to confirm when purchasing.

HCM370B&375B-MP HIGH ACCURACY 3D DIGITAL COMPASS
○Inclinometer ○3D compass ○Digital inclinometer ○Accelerometer ○Gyro ○North finder ○INS&IMU
SINCE2008 ·Inertial Attitude Measurement Manufacturer
▶INTRODUCTION
HCM370B/HCM375B-MP is a high-precision 3D compass with high resolution, strong anti-noise ability,
and stable temperature drift; it adopts advanced hard iron and soft iron calibration algorithms, and uses
high-precision accelerometers for tilt compensation, allowing it provide high accurate heading at any roll
angle in 360 °. In an environment with fixed interference, this product can provide high accurate
measurement.
Long strip shape, the width is only 1.95CM. It is IP67 grade and is more suitable for drilling measurement;
it is small and consumes low power, which can be quickly and conveniently integrated into various
products. Both complete product and PCBA of the senor are available.
This product integrates a three-axis magnetic field sensor and a three-axis acceleration sensor. It uses
an industrial single-chip computer with high reliability and strong anti-interference ability to calculate
heading data in real time, and uses a three-axis accelerometer to compensate for a wide range of tilt
angles. With high-performance, high-stability products, small size and low power consumption, make it
suitable for many fields such as handheld devices, mobile devices, antenna stability, vehicles, and
system integration.
▶MAIN FEATURE
★Heading Accuracy: 0.5° ★Roll Measure Range:±180°
★Tilt Resolution: 0.1° ★Tilt Accuracy: <0.2°(Full Range)
★Working Temp.: -40℃~+85℃★Size : L110×W19.5×H19.5mm
★With Hard And Soft Magnetic Calibration ★RS232/RS485/TTL Output
▶APPLICATION
★Satellite antenna search satellite ★Marine navigation surveying and mapping
★GPS integrated navigation ★Antenna servo control
★Gun emission system ★Infrared imager
★Laser range finder ★Map for plotter
★ROV underwater robot navigation ★Oceanography measurement instruments
★Special occasion robot ★Unmanned aircraft

HCM370B&375B-MP HIGH ACCURACY 3D DIGITAL COMPASS
○Inclinometer ○3D compass ○Digital inclinometer ○Accelerometer ○Gyro ○North finder ○INS&IMU
SINCE2008 ·Inertial Attitude Measurement Manufacturer
▶PRODUCT PARAMETERS
HCM370B / HCM375B PARAMETER
Heading
Heading Accuracy
0.5° Tilt < 10°
2.0° Tilt < 60°
3.0° Tilt < 80°
Resolution
0.1°
Tilt
Pitch Accuracy
0.1°<15°（Measure Range）
0.1°<30°（Measure Range）
0.1°<60°（Measure Range）
0.2°<85°（Measure Range）
Pitch Range
±85°
Roll Accuracy
0.1°<15°（Measure Range）
0.1°<30°（Measure Range）
0.1°<60°（Measure Range）
0.2°<180°（Measure Range）
Roll Range
±180°
Resolution
0.1°
Calibration
Hard Magnetic Calibration
Available
Soft Magnetic Calibration
Available
Magnetic Filed Interference
Calibration Method
Rotate 360° Horizontally;
Vertical Rotation(Optional)
RS-232/RS485/TTL
5Pin Quick Plug Connector
Interface
Start Delay
<50ms
Max Output Rate
20Hz/s
Communication Rate
2400~115200baud
Output Format
Binary High Performance Protocol
Power Supply
Power Voltage
（Default）DC+5V
Current(Max)
30ma
Ideal Current
26ma
Sleep Mode
TBD
Environment
Working Temp.
-40℃~+85℃
Storage Temp.
-40℃~+85℃
Anti-Shock Performance
100g
Protection Level
IP67
Electromagnetic
Compatibility
According TO EN61000 and BT17626
Mtbf
≥40000 Hour/Time
Insulation Resistance
≥100M.O.
Anit-Impact
100g@11ms、3 Axial Direction (Half Sinusoid)
Anti--Shock
10grms、10～1000Hz
Dimension
L110×W19.5×H19.5mm
Weight
70g(Not Include Cable)

HCM370B&375B-MP HIGH ACCURACY 3D DIGITAL COMPASS
○Inclinometer ○3D compass ○Digital inclinometer ○Accelerometer ○Gyro ○North finder ○INS&IMU
SINCE2008 ·Inertial Attitude Measurement Manufacturer
▶产品订购信息
E.g : HCM375B-232-MP: enclosure packaging / horizontal installation / RS232 digital interface / 24-point
calibration.
▶ELECTRICAL CONNECTION
HCM370B Single Board 232/TTL Output Wiring Definition
Cable
Color
Definition
BLACK
RED
YELLOW
GREEN
GND
Power negative
DC 5V
Power positive
TTL/RS232(RXD)
OR RS485(D-)
TTL/RS232(TXD)
OR RS485(D+)
HCM370B single board RS232/TTL output wiring map
HCM370B single board RS485 output wiring map
HCM375B Wiring Definition
Cable
Color
Definition
BLACK
PINK
BLUE
BROWN
GND
Power
negative
RS232(RXD)
OR
RS485(D+)
RS232(TXD)
OR
RS485(D-)
DC 5V
Power positive
MP
HCM37
Output interface
232 : RS232
485 : RS485
TTL : UART TTL
0: PCB single board
5: with housing
Sealed mode
B: Horizontal
V: Vertical
Installation method

HCM370B&375B-MP HIGH ACCURACY 3D DIGITAL COMPASS
○Inclinometer ○3D compass ○Digital inclinometer ○Accelerometer ○Gyro ○North finder ○INS&IMU
SINCE2008 ·Inertial Attitude Measurement Manufacturer
▶SINGLE BOARD SIZE CHART
SIZE : L76×W16.5×H9.3mm
▶SHELL SIZE CHART
SIZE : L110×W19.5×H19.5mm
▶MEASURING DIRECTIONS&FIX
HCM375B 3D electronic compass azimuth is using geomagnetic principle, so it is very important to select
a minimum magnetic interference environment for installation positon. Please place and install the it
away from the iron, magnets, engines and other magnetic objects as much possible as you can. Need
control over 30CM distance(different magnetic interfere with the compass in different distance ) at least
even there are these magnetic medium around . In order to ensure optimal measurement environment
please must use the M3 anti-interference screws for installation .
Although it can compensate the moderate deviation in the stable magnetic environment, but it can not
compensate the changed magnetic interference. Please pay much attention to the wire with DC will
generates a magnetic field , because if the DC change then the magnetic field will also change in size .
The battery also is another interference source of changing . Each installation is different, and the user
must evaluate the feasibility of installation under all possible operating environment.
The optimal heading accuracy of it can reach 0.3°~0.5°, this undergo a rigorous validation indisputable,
the most scientific test method is equally crucial. The test method we recommend is: Please install the
electronic compass to a vertical and erect aluminum pole (non-magnetic material), then proceed with

HCM370B&375B-MP HIGH ACCURACY 3D DIGITAL COMPASS
○Inclinometer ○3D compass ○Digital inclinometer ○Accelerometer ○Gyro ○North finder ○INS&IMU
SINCE2008 ·Inertial Attitude Measurement Manufacturer
heading accuracy measurement (of course the rotating rod perpendicular to the rotating platform, as
much as possible to avoid large external magnetic field interference). Doing so can reduce the
compass turning radius, to scientifically improve the measurement accuracy. This is just to provide the
installation of the laboratory, must be flexible to deal with the specific situation.E.g: is mounted in the car,
HCM505B should do its installation in the perpendicular to the movement direction.
HORIZONTAL INSTALLATION
VERTICAL INSTALLATION

HCM370B&375B-MP HIGH ACCURACY 3D DIGITAL COMPASS
○Inclinometer ○3D compass ○Digital inclinometer ○Accelerometer ○Gyro ○North finder ○INS&IMU
SINCE2008 ·Inertial Attitude Measurement Manufacturer
▶CALIBRATION DESCRIPTION
Calibration lemmas:
1) The accuracy of testing compass cannot reach the requirements.
2) compass installation environment has magnetic interference, the interference is fixed, and the
interference magnetic field and compass installation will not happen again in distance changes
(example: compass to be installed above an iron material, because the iron will have magnetic
interference, at this time then need to rotate and calibrate the iron and compass, and the iron and
compass will not be separated when using, once they are separated then need to recalibrate. If the iron
size is not fixed, or with a compass distance change is not fixed, the interference cannot be calibrated,
only can install it in a very far away, safe distance control in above 30cm).
1) correctly connect to the signal output interface, then power on.
2) Select automatic calibration mode or manual calibration mode:
Automatic calibration mode: send the command "68 04 00 44 48" (click the SET button after selecting
automatic calibration);
Manual calibration mode: send the command "68 04 00 43 47" (click the SET button after selecting
manual calibration);
Send the calibration start command in hexadecimal format: "68 04 00 08 0C" (click the start button).
3) The electronic compass will return a response command, and the compass will return a response
every time it takes a point. Please refer to the communication protocol.
4) After taking 24 calibration points according to the calibration procedure, send the stop calibration
command: "68 04 00 09 0D" (click the stop button), at this time the electronic compass pauses for about
1 second, the internal CPU automatically calculates the sampled data and returns a set of data which
represents the scoring value of the obtained data.
5) Save the calibration command: Send the command "68 04 00 0A 0E" (click the save button), the
compass will return a response command. If the save is successful, it can work normally. If the
unsuccessful message is returned, the user will recalibrate.
6) after 2) Send the calibration start command to start the calibration, keep the compass stable, and wait
for the first point to be sampled.
7) After the first point is sampled, rotate the module about 90° horizontally to keep the compass stable
and wait for the next point to be sampled.
8) Repeat the above steps until 24 points are sampled, and then send the calibration command and click
stop button.
9) Send the calibration save command to end the calibration.
When calibrating, if the distance between the magnetic interference source and the compass itself
changes, the accuracy will be affected.
Note: When starting to calibrate and take points, calibrate the compass corresponding to the following
series of calibration charts. Please note that these points are not absolute headings, but a relative
heading change value with reference to the heading which is sampled at the first point, and sampling
angle vaule error is allowed. Do not require strict accuracy.

HCM370B&375B-MP HIGH ACCURACY 3D DIGITAL COMPASS
○Inclinometer ○3D compass ○Digital inclinometer ○Accelerometer ○Gyro ○North finder ○INS&IMU
SINCE2008 ·Inertial Attitude Measurement Manufacturer
The calibration steps are as follows:
The starting point of the calibration can be in any point
in 360°, as long as it keeps about 90° for every change
of angle (accuracy is not required).
Example picture Pic.A: Starting point H=0°, R=0°,
P=+15° (first adjust the pitch value P) Please keep this
position for 2 to 3 seconds, and the system will take the
first point. After taking the first point, rotate it 90°
horizontally to sample 2nd point, so as for 3rd and 4th
point.
After taking the 4th point, both H and R remain
unchanged, and then increase the +P angle value.
Refer to Pic.B: Starting point H=0°, R=0°, P=+70° , the
same way to take point 5th,~8th.
After taking the 8th point, both H and R remain
unchanged, and then calibrate the -P angle. Refer to
Figure Pic.C: starting point H=0°, R=0°, P=-15°, and
take point from 9th to 12th.
After taking the 12th point, H and R remain unchanged,
and then increase the -P angle value.
Refer to Pic.D: Starting point H=0°, R=0°, P=-70° , and
take point from 13th to 16th as the same way.

HCM370B&375B-MP HIGH ACCURACY 3D DIGITAL COMPASS
○Inclinometer ○3D compass ○Digital inclinometer ○Accelerometer ○Gyro ○North finder ○INS&IMU
SINCE2008 ·Inertial Attitude Measurement Manufacturer
P calibration is completed after the 16th point is collected,
and then R, R (roll value) can be calibrated alternately.
Refer to Pic.E: Starting point H=0°, R=+15°, P=0° Please
keep this attitude for 2 to 3 seconds, the system will take
the 17th point. After taking the 17th point, rotate it
horizontally by 90° and change the negative roll value
R=-15°. Keep this posture for 2 to 3 seconds without
moving, and the system will take the 18th point. Finish
picking the 18th point.
Rotate it horizontally by 90°, change the positive and roll
value R=+15°, keep this posture for 2 to 3 seconds, and
the system will take the 19th point. After taking the 19th
point, rotate it horizontally by 90°, change the negative
roll value R=-15°, keep this attitude for 2 to 3 seconds, and the system will take the 20th point.
After taking the 20th point, increase R (roll value) for
calibration. Refer to the picture Pic.F: Starting point H=0°,
R=+70°, P=0° Please keep this attitude for 2 to 3 seconds,
the system will take the 21st point. After taking the 21st
point, rotate it horizontally by 90° and change the
negative roll value R=-70°. Keep this posture for 2 to 3
seconds without moving, and the system will take the
22nd point. After taking the 22nd point, rotate it
horizontally by 90°, change the positive roll value R=+70°,
keep this posture for 2 to 3 seconds, and the system will
take the 23rd point. After taking the 23rd point, rotate it
horizontally by 90°, change the negative roll value R=-70°,
keep this attitude for 2 to 3 seconds, and the system will
take the 24th point. Send stop command---compass response---send save command again---compass
response save successfully!

HCM370B&375B-MP HIGH ACCURACY 3D DIGITAL COMPASS
○Inclinometer ○3D compass ○Digital inclinometer ○Accelerometer ○Gyro ○North finder ○INS&IMU
SINCE2008 ·Inertial Attitude Measurement Manufacturer
▶COMMUNICATION PROTOCOL
1. DATA FRAME FORMAT：（8 Bits Date，1 Bit Stop，No Check，Default Baud Rate 9600）
Identifier
(1byte)
Date Length
(1byte)
Address code
(1byte)
Command word
(1byte)
Date
domain
Check sum
(1byte)
68
Identifier：Fixed68H
Data length：From data length to check sum（including check sum）length
Address code：Accumulating module address，Default :00
Date domain will be changed according to the content and length of command word
Check sum：Data length、Address code、Command word and data domain sum,No carry.
2. COMMAND WORD ANALYSIS
code
Meaning/example
explain
0X04
Read Pitch/Roll/Heading
angle command at the same
time 68 04 00 04 08
Data field （0byte）
No data field command
0X84
sensor repsond
Eg.: 68 0D 00 84 00 10 50 10
10 05 01 04 01 1C
Data field（9byte）
AA AB BB CC CD DD EE EF FF
AA AB BB:3 characters indicate Pitch.
CC CD DD: 3 characters indicate Roll.
EE EF FF: 3 characters indicate Heading.
The angle format has the same parsing method as Pitch,
Roll and Heading
The angle in the left example is
Pitch: +010.50°,
Roll:-010.05°，
Heading+104.01°
0X06
Set magnetic declination
command.
68 06 00 06 02 08 16
Data field (2byte): SA AB
S is the sign, 0 plus, 1 minus,
AA: two integers, B: one decimal
Example: 02 08 is +20.8°
0X86
sensor repsond
Eg.: 68 05 00 86 00 8B
Data field（1byte）
The number in the data field represents the result of the
sensor response.
00 setting succeeded FF setting failed
0X07
Read magnetic declination
command.
68 04 00 07 0b
Data field（0byte）
no data command
0X87
sensor repsond
Eg.: 68 06 00 87 02 08 97
Data field (2byte): SA AB
S is the sign, 0 plus, 1 minus,
AA: two integers, B: one decimal
Example: 02 08 is +20.8°
The number in the data field represents the result of the
sensor response
0X08
Start calibration command
68 04 00 08 0C
data field（0byte）
no data command
0X88
sensor repsond
Eg.: 68 05 00 88 00 8D
data field（1byte）
The number in the data field represents the result of the

HCM370B&375B-MP HIGH ACCURACY 3D DIGITAL COMPASS
○Inclinometer ○3D compass ○Digital inclinometer ○Accelerometer ○Gyro ○North finder ○INS&IMU
SINCE2008 ·Inertial Attitude Measurement Manufacturer
sensor response
00 start succeeded FF start failed
Note: compass will return data every point is take until calibration stop, format as below:
0X88
Compass reply calibration take
point number
Eg.: 68 05 00 88 07 94
Data field（1byte）
The number in the data field that represents the
calibration point picked up by the sensor (hexadecimal)
0X09
Stop calibration command
68 04 00 09 0D
data field（0byte）
no data command
0X89
sensor repsond
Eg.: 68 10 00 89 00 00 78 00
01 13 00 00 40 00 64 74 5B
Data field（12byte）
SA AA BB SC CD DD SE EF FF SG GG HH
SA AA BB: 3 characters represent the calibration residual
coefficient of the sampling point. < 1 is normal. The
smaller the value is, the more reliable the calibration is.
SC CD DD: The three characters represent the uniformity
of the distribution of sampling points in all directions of
the 3D calibration. The score should be less than 6%.
The smaller the value, the more uniform the distribution
of sampling points is.
SE EF FF: 3 characters represent the distribution range
of the tilt Angle of the 3D calibration sampling point, and
the score should be between 0 and 1. The smaller this
value is, the more extensive the spatial coverage of the
sampling point is.
SG GG HH: 3 characters represent the amplitude of the
single side of the maximum Angle of pitch Angle and roll
Angle of the compass calibration sampling point, and the
score should be > 45°. The larger this value is, the more
sufficient the spatial distribution of the calibration
sampling point will be.
Note: the above score values are for reference only. If the
above score requirements are met, it means that the
sampling conditions of this calibration are excellent and
the accurate azimuth accuracy is not necessarily
obtained.
The first byte high 4 bits is sign bit, 1 negative, 0 positive；
The first byte low 4 bits is hundreds.
The second byte high 4 bites are tens.
The second byte low 4 bites are ones.
The third byte high 4 bits are tenths.
The third byte low 4 bits are percentile.
In the left example, the Angle is
SA AA BB：0.78
SC CD DD：1.31%
SE EF FF：0.4
SG GG HH：64.74°
0X44
Auto calibration mode
command
68 04 00 44 48
Data field（0byte）
no data command
0XC4
sensor repsond
Data field（1byte）

HCM370B&375B-MP HIGH ACCURACY 3D DIGITAL COMPASS
○Inclinometer ○3D compass ○Digital inclinometer ○Accelerometer ○Gyro ○North finder ○INS&IMU
SINCE2008 ·Inertial Attitude Measurement Manufacturer
Eg.: 68 05 00 C4 00 C9
The number in the data field represents the result of the
sensor response
00 start succeeded FF start failed
0X43
Manual calibration mode
command
68 04 00 43 47
Data field（0byte）
no data command
0XC3
sensor repsond
Eg.: 68 05 00 C3 00 C8
Data field（1byte）
The number in the data field represents the result of the
sensor response
00 start succeeded FF start failed
0X45
Manual collecting command
68 04 00 45 49
data field（0byte）
no data command
0X88
24 points taken reply
command：
68 05 00 88 01 8E (1 )
68 05 00 88 02 8F (2 )
68 05 00 88 03 90 (3 )
...
68 05 00 88 18 A5 (24 )
data field（1byte）
The number in the data field that represents the
calibration point picked up by the sensor (hexadecimal)
0X0A
Save calibration command
68 04 00 0A 0E
Data field（0byte）
no data command
0X8A
sensor respond command
Eg.: 68 05 00 8A 00 8F
Data field（1byte）
The number in the data field represents the result of the
sensor response.
00 succeeded FF failed
0X0B
Set baud rate command
68 05 00 0B 02 12
Data field（1byte）
baud rate: defaulted as 9600
00 indicate 2400 01 indicate 4800
0 indicate 9600 03 indicate 19200
04 indicate 38400 05 indicate 115200
0X8B
sensor respond command
Eg.: 68 05 00 8B 00 90
Data field（1byte）
The number in the data field represents the result of the
sensor response.
00 succeeded FF failed
0X0F
Set sensor address
command
68 05 00 0F 01 15
Data field（1byte）
The address of XX module ranges from 00 to EF.
Note: Our products have a unified address:FF. If you
forget the address set during the operation, you can
use FF address to operate the product and still
respond normally.
0X8F
sensor respond command
Eg.: 68 05 00 8F 00 94
Data field（1byte）,
The number in the data field represents the result of the
sensor response.
00 succeeded FF failed
0X0C
Set angle output mode.
68 05 00 0C 00 11
Data Field (1byte)
00: Q&A 01: Automatic output
Factory default: Q&A
0X8C
sensor respond command
Data field（1byte）,

HCM370B&375B-MP HIGH ACCURACY 3D DIGITAL COMPASS
○Inclinometer ○3D compass ○Digital inclinometer ○Accelerometer ○Gyro ○North finder ○INS&IMU
SINCE2008 ·Inertial Attitude Measurement Manufacturer
Eg.:68 05 00 8C 00 91
The number in the data field represents the result of the
sensor response.
00 succeeded FF failed
0X2A
Set angle output mode
68 05 00 2A 00 2F
Data field（1byte）
00: Horizontal installation
01: Vertical installation (connector facing down)
Factory default: horizontal installation
Horizontal installation: When the compass is placed horizontally, the roll and pitch angle
output is zero degrees.
Vertical downward installation: When the compass is placed vertically downward, the roll
and pitch angle output is zero degrees.
0XAA
sensor respond command
Eg.:68 05 00 AA 00 AF
Data field（1byte）,
The number in the data field represents the result of the
sensor response.
00 succeeded FF failed
0X41
Query installation type
command
68 04 00 41 45
Data field（0byte）
0XC1
sensor respond command
Eg.:68 05 00 C1 00 C6
Data field（1byte）,
The number in the data field represents the result of the
sensor response
00 horizontal installation 01 vertical installation
0X42
Query output type command
68 04 00 42 46
Data field（0byte）
0XC2
sensor respond command
Eg.:68 05 00 C2 00 C7
Data field（1byte）,
The number in the data field represents the result of the
sensor response
00: Q&A 01: Automatic output

HCM370B&375B-MP HIGH ACCURACY 3D DIGITAL COMPASS
○Inclinometer ○3D compass ○Digital inclinometer ○Accelerometer ○Gyro ○North finder ○INS&IMU
SINCE2008 ·Inertial Attitude Measurement Manufacturer
Add：4th Floor Block 1, COFCO(FUAN) Robotics Industrial Park , Da Yang Road No. 90,
Fuyong Distict, Shenzhen City, China
Tel ：[phone] (86) 755-29761269
Fax：[phone]
E-mail：[email protected]
Web：www.rion-tech.net