Rion HCM705B User manual

HCM705B-High Accuracy Gyro Compass
SPECIFICATIONS
Item No.：HCM705B
Desc.：High Accuracy Gyro Compass
Production implementation standard reference
● Enterprise quality system standards: ISO9001: 2008 standard (certification number: 128101)
● Tilt sensor production standards: GB / T 191 SJ 20873-2003 inclinometer general specification of Level
● Gyro accelerometer test standard: QJ 2318-92 Gyro accelerometer test methods
● Software development reference standard: GJB 2786A-2009 military software development General
requirements
● Product environmental testing standards: GJB150
● Electromagnetic anti-interference test standards: GB / T 17626
●Version：Ver.01
●Date: Jul.22nd,2015

HCM705B-High Accuracy Gyro Compass
General Description
HCM705B is a high accuracy triaxial electronic compass, using the the US patent technology of hard
magnetic and soft magnetic calibration algorithm, to make sure the compass in a magnetic field
interference environments has best effect through 3D calibration method , HCM705B integrated
three-axis flux-gate sensor, through the CPU real-time calculating heading , and use triaxial
accelerometer to compensate the heading Angle of large scope inclination.Electronic compass integrates
high precision MCU control, output way various, in which the standard interface including RS232 / RS485
/ TTL interface...etc, also can accept other communication interface customization.
HCM705B with small volume, low power consumption, can be applied in antenna stable, vehicles,
systems integration, and many other fields, high shock resistance and high reliability make compass
work normally under the extremely harsh environment, more suitable for the miniaturization of today's
military precision measuring integrated control system.
Features
●Heading accuracy: 0.3°～0.5° ●Roll angle measuring range :±180°
●Tilt angle resolution: 0.1° ●Tilt angle accuracy: 0.2°
●With hard magnetic ,soft magnetic and angle compensation ●Size: L94×W31×H24mm
●Standard RS232/RS485/TTL output interface ●Wide temperature : -40℃～+85℃
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

HCM705B-High Accuracy Gyro Compass
Ordering information
E.g：HCM705B-232：360tilt 3D sealed with enclosure /RS232 output
Electrical Characteristics
Compass
heading
parameter
The best heading accuracy
0.3° tilt <10°
1.0° tilt <180°
Resolution
0.1°
Compass tilt
parameter
Pitch accuracy
0.1°<15°（Measuring range）
0.1°<30°（Measuring range）
0.1°<60°（Measuring range）
0.2°<90°（Measuring range）
Pitch tilt range
±85°
Roll accuracy
0.1°<15°（Measuring range）
0.1°<30°（Measuring range）
0.1°<60°（Measuring range）
0.2°<180°（Measuring range）
Roll tilt range
±180°
Resolution
0.1°
Calibration
Hard iron calibration
Yes
Soft iron calibration
Yes
Magnetic field interference calibration
method
24 points(3D calibration)
Physical
features
Dimension
L94×W31×H24mm
Weight
20g
RS-232/RS485/TTL interface connector
5PIN connector
Interface
features
Start delay
<50MS
Maximum output rate
20Hz/s
Communication rate
2400 to19200baud
Output format
Binary high performance protocol
Power
Power supply
（Default）DC+5V
（Customized）DC9～36V
Current(Maximum)
20mA
HCM705B Technical Data

HCM705B-High Accuracy Gyro Compass
Ideal mode
18mA
Sleep Mode
TBD
Enviroment
Operating range
-40℃～+85℃
Storage temperature
-40℃～+100℃
Resistance shock performance
2500g
Electromagnetic
compatibility
According to EN61000 and GBT17626
MTBF
≥40000 hours/times
Insulation
resistance
≥100M
Shock
resistance
100g@11ms、3Times/Axis(half sinusoid)
Anti-vibration
10grms、10～1000Hz
Weight
80g(without cable)
Electrical Connection
Line
color
function
BLACK
WHITE
GREEN
RED
GRAY
GND
Power
Negative
RS232(RXD)
Or RS485(D+)
RS232(TXD)
Or RS485(D-)
Vcc 5V
Power supply positive
FACTORY
Use only
HCM705B Measuring Directions&Fix
The azimuth of HCM705B 3D electronic compass is using geomagnetic principle, so it is very important
to select a minimum magnetic interference environment for installation . Please install the HCM505B
away from the iron, magnets, engines and other magnetic objects as much possible as you can. Need
control over 30CM distance(different magnetic interfere the compass in different distance ) at least even
there are these magnetic medium around . In order to ensure best measurement environment please
must use the M3 anti-interference screws for installation .
HCM705B electronic compass with 1 meter cable, RION company optional cable can be 10
meters.The sensor cable as short as possible to get minimum noise. Although HCM705 to compensate
the moderate deviation in the stable magnetic environment, but it CAN NOT compensate the changeable
magnetic interference. Please special pay much more attention to the wire carry with a direct current to
create the magnetic field , because if the direct current change, size of the magnetic field will also change.
Battery is also another change of interference sources. Every installation is different and the user must
evaluate the installation feasibility of all possible operating conditions.

HCM705B-High Accuracy Gyro Compass
The best heading accuracy of HCM705B 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 HCM705B electronic compass to a vertical and erect aluminum pole (non-magnetic material),
then proceed with 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, HCM705B should do its installation in the perpendicular to the movement direction.

HCM705B-High Accuracy Gyro Compass
Dimension
Size：L*W*H:94*31*24MM

HCM705B-High Accuracy Gyro Compass
HCM705B Calibration methods:
Calibration lemmas:
1) The accuracy of testing compass can not reach the requirements;
2) compass installation environment have 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 compass distance change is not fixed, the
interference can not be calibrated,only can install it in a very far away , safe distance control in
over 30cm).
1）Correctly connect the HCM compass to the RS232 communication port , turn on the power.Correctly
2）Select automatic calibration mode or manual calibration mode; Automatic calibration MODE:
send commands "6804 004448" (or click on the software A - MODE)
Manual calibration MODE: send commands ", 6804, 004347 "(or click on the software M - MODE)
using hexadecimal format send calibration START command:" 68 00 04 08 0C "(or click RION’ s
3D debugging software" CALI - START ")
3）HCM compass will return the response command, at the same time the compass take each point will
return a response, please refer to the communication protocol.
4）With the following rotation rules after minimum taking the 12 calibration points, then send the stop
calibration command: 68 04 00 09 0D (or click the RION 3D debugging software "CALI-STOP"
button), the compass will pause about 2 seconds, the internal CPU automatically calculate just
sampling data, after the calculation will return a set of data, is the percentage value of the data just gain.
5)Then send the save calibration command: 68 04 00 0A 0E "(or click RION 3D debugging
software" CALI-SAVE "Save button), the compass will return the answer reply command, you can work
properly if successfully saved, if return unsuccessful information, the user can repeat the above
calibration steps also can return to the compass factory default calibration data work.
6) Following 2) Send a calibration start command to begin calibration, keep the stability of the module
posture, waiting for the first point is sampled.
7) after the first point sampling, rotate module around 90 degrees horizontally,to keep the module stability,
wait for the next point is sampled. (Refer to the below diagram calibration steps)
8) Repeat the above steps until the sample to 18 points, and then send the calibration stop button.
9) Send calibration save command to end the calibration .
When calibrate, if the distance of the magnetic interference source with the compass occur
change , the percentage of the calibration will be lower, the precision will be weaker.
Note: When you start the calibration and take points, move the compass to the following location, please
note that these points are not absolute heading orientation, but with reference to the first point sampling
heading orientation relative orientation change value. That is, you do not need to know which position the
real North Pole is in.Further for example, the 90degree rotation and 15 degrees pitch only one reference
value, to allow a certain sampling angle value error, unnecessarily strictly require very precise. Take at
least below12 points calibration, it is recommended that 24 points ,the user can sample more points in

HCM705B-High Accuracy Gyro Compass
order to improve the accuracy, up to 50 points at most, the same sampling principle with the following
methods, just a sampling of the pitch angle and roll angle point will increase.
Note: When you start the calibration and take points, move the compass to the following location, please
note that these points are not absolute heading orientation, but with reference to the first point sampling
heading orientation relative orientation change value. That is, you do not need to know which position the
real North Pole is in.Further for example, the 90degree rotation and 15 degrees pitch only one reference
value, to allow a certain sampling angle value error, unnecessarily strictly require very precise. Take at
least below12 points calibration, it is recommended that 24 points ,the user can sample more points in
order to improve the accuracy, up to 50 points at most, the same sampling principle with the following
methods, just a sampling of the pitch angle and roll angle point will increase.
The calibration steps are as follows:
The standard starting point can be anyone azimuth of
360 °, as long as each change angle to keep the basic
level about 90 ° to change (do not require too precise).
Example as left Pic.A: starting point for H = 0 °, R = 0 °,
P = +15 ° (firstly calibrate the pitch value P) please
keep this posture for 2 to 3 seconds don’t move, the
system will take the first point .
After took the first point, again rotate 90 ° horizontally,
please keep this posture for 2 to 3 seconds don’t
move, the system will take the second point.
After took the second point, again rotate
90 °horizontally, please keep this posture for 2 to 3 seconds don’t move, the system will take
the third point.
After took the third point, again rotate 90 ° horizontally, please keep this posture for 2 to 3
seconds don’t move, the system will take the fourth point.
After took the fourth point, H and R are the same, and
then increase + P angle value.
Refer to the left Pic.B: starting point H = 0 °, R = 0 °, P =
+55 ° ,please keep this posture for 2-3 seconds don’t
move, the system will take the fifth point.
After took the fifth point, again rotate 90 °horizontally,
please keep this posture for 2 to 3 seconds don’t
move,
the system will take the sixth point.
After took the sixth point, again rotate 90 °horizontally,
please keep this posture for 2 to 3 seconds don’t move, the system will take the seventh point.
After took the seventh point, again rotate 90°horizontally, please keep this posture for 2 to 3
seconds don’t move, the system will take the eighth point.

HCM705B-High Accuracy Gyro Compass
After took the eighth point, H and R are the same , then
calibrate –P angle .
Refer to the left Pic.C: starting point H=0°，R=0°,
P=-15°,please keep this posture for 2-3 seconds don’t
move, the system will take the ninth point.
After took the ninth point, again rotate 90 °horizontally,
please keep this posture for 2 to 3 seconds don’t move,
the system will take the tenth point.
After took the tenth point, again rotate 90 °horizontally,
please keep this posture for 2 to 3 seconds don’t move,
the system will take the eleventh point.
After took the eleventh point, again rotate 90 °horizontally, please keep this posture for 2 to 3
seconds don’t move, the system will take the twelfth point.
After took the twelfth point, H and R are the same , then
increase –P angle value .
Refer to the left Pic.D: starting point H=0°，R=0°,
P=-55°,please keep this posture for 2-3 seconds don’t
move, the system will take the thirteenth point.
After took the thirteenth point, again rotate
90 °horizontally, please keep this posture for 2 to 3
seconds don’t move, the system will take fourteenth
point.
After took the fourteenth point, again rotate
90 °horizontally, please keep this posture for 2 to 3 seconds don’t move, the system will take
the fifteenth point.
After took the fifteenth point, again rotate 90 °horizontally, please keep this posture for 2 to 3
seconds don’t move, the system will take the sixteenth point.
After took the sixteenth point then finished P
calibration, then calibrate R,R(Roll value)can calibrate
alternately .
Refer to the left Pic.E: starting point H=0°，R=+15°,
P=0°,please keep this posture for 2-3 seconds don’t
move, the system will take the seventeenth point.
After took the seventeenth point, again rotate
90°horizontally, alternate the negative Roll value
R=-15°,please keep this posture for 2 to 3 seconds
don’t move, the system will take the eighteenth point.
After took the eighteenth point, again rotate
90°horizontally, alternate the positive Roll value R=+15°,please keep this posture for 2 to 3

HCM705B-High Accuracy Gyro Compass
seconds don’t move, the system will take the nineteenth point.
After took the nineteenth point, again rotate 90 °horizontally,alternate the negative Roll value
R=-15°,please keep this posture for 2 to 3 seconds don’t move, the system will take the
twentieth point.
After took the twenty second point, again rotate
90°horizontally, alternate the positive Roll value
R=+55°,please keep this posture for 2 to 3 seconds
don’t move, the system will take the twenty third point.
After took the twenty third point, again rotate
90 °horizontally,alternate the negative Roll value
R=-55°,please keep this posture for 2 to 3 seconds
don’t move, the system will take the twenty fourth point.
Sending stop command---compass
response---Re-sending save command---compass
response save successfully.
RION’s 3D Software
You can download the RION angle debugging software from RION’s official website for the
preliminary angle debugging, also you Can download public version of the comassistant
software on line for using
Open/Close：Open and close COM port;
Com: Select the the device corresponding to the COM port
Address: Fill in the sensor current address code, the factory default is 00

HCM705B-High Accuracy Gyro Compass
Set Address: Set the sensor address code input box on the right to enter the desired address code, click
Set Addr button
Save Data: Save the data, click here data can be synchronized Save angle data, the file is stored by
default in the C: ---- COMDATA file
Set Zero: Set relative zero, the sensor current angle is 00.00 degrees
Cancel Zero: Unset the relative zero, to restore the sensor to the factory absolute zero;
Baud Rate: Select the sense baud rate , the factory default is 9600;
Set Baud Rate: Set the sensor baud rate, on the right of the selection box to select corresponding baud
rate then click SetB.R. button;
Auto Output: Switch the sensor to automatically output mode, in the automatic output mode can be filled
with different output frequency in Hz;
Catechism: The sensor switch to answer pattern, such as choosing the answer type, must input “send
command ”( command, please refer to the specification ) on the left of “Send Command”
input box, but also can fill in the transmit frequency in the Send Data, the unit Hz;
Mag. Dec.: Magnetic declination setting, in the right box directly enter the local magnetic declination, click
“Mag.Dec.” Button to confirm .
Calibration: compass calibration forum
Start: Start calibration
Stop: Stop the calibration (Click this button, keep the compass shaking state to avoid incorrect calibration
of the acquisition)
Save: stop calibration and save data. (Specific calibration method please refer to this specification
calibration description)
Note: after install the RION’s debugging software, if can not open, please operate by the following steps
( please appear to the administrator status to operate ):
1）Copy these three files mscomm.srg、mscomm32.ocx、mscomm32.dep from the folder to
C:/Windows/system32 path below。
2）Click “Start” –“run” --regsvr32 mscomm32.ocx，You are prompted to install successful dialog。
Product Communication Protocol
HCM705B is based on TRAX, increase the communication protocol of RION.
MCU read TRAX azimuth, roll, pitch, magnetic field X, magnetic field Y, magnetic field Z, azimuth Status.
Through a serial port output azimuth, roll, pitch and azimuth state data of four parameters.Magnetic field
is used to determine the coefficient of magnetic interference.
一、Data Frame Format ：（8 bits of data bits，1 stop bit,no check, the default rate 9600）
Identifier
(1byte)
Data Length
(1byte)
Address code
(1byte)
Command
word
(1byte)
Data
Domains
Checksum
(1byte)
68h
Identifier：Fixed 68H
Data length：From data length to checksum（including checksum）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.

HCM705B-High Accuracy Gyro Compass
二、Command word analysis
Desc.
Meaning/Example
Description
0X04
Meanwhile read
Pitch、Roll、Heading、
Angle command
68 04 00 04 08
Data domain（0byte）
No Data domain command
0X84
Sensor answer reply
E.g
68 0D 00 84 00 10 50 10 10 05 01
04 01 23
Data domain（9byte）
AA AB BB CC CD DD EE EF FF
AA AB BB:3 Characters is Pitch Axis
CC CD DD: 3 Characters is Roll Axis
EE EF FF: 3 Characters is Heading angle
Angle format with same analytic method as Pitch、Roll、
Heading
On the left example , the angle is
: Pitch: +010.50°,Roll:-010.05°，Heading+104.01°
0X06
Setting declination command
68 06 00 06 02 08 16
Data domain(2byte）SA AB
S is symbol 0 positive 1 negative
AA: two digits integer，B: two digits decimals
E.g：02 08 is +20.8 deg
0X86
Sensor answer reply
E.g: 68 08 00 86 00 8E
Data domain（1byte）
Data domain in the number means the sensor response
result
00 Setting successfully
FF Setting failure
0X07
Read declination command
68 04 00 07 0b
Data domain（0byte）
No Data domain command
0X87
Sensor answer reply
E.g: 68 06 00 87 02 08 97
Data domine（2byte）
Data domain in the number means the sensor response
result
0X08
Start calibration command
68 04 00 08 0C
Data domain（0byte）
No Data domain command
0X88
Sensor answer reply
E.g: 68 05 00 88 00 8D
Data domain（1byte）
Data domain in the number means the sensor response
result
00 Start success FF Start failure
Note: after each module take a point returns data at a time, until the stop calibration, format as below
0X88
Sensor replay calibration points
E.g: 68 05 00 88 07 94
Data domain（1byte）
The number in the data domain indicates the number
sensor collects the calibration points (hexadecimal)
0X09
top calibration command
68 04 00 09 0D
Data domain（0byte）
No Data domain command
0X89
Sensor answer reply command
E.g: 68 05 00 89 XX CS
Data domain（4byte）
XX is 00 can receive，FF can not receive
0X0A
Save calibration command
68 04 00 0A 0E
Data domain（0byte）
No Data domain command
0X8A
Sensor answer reply command
Data domain（1byte）

HCM705B-High Accuracy Gyro Compass
E.g: 68 05 00 8A 00 8F
Data domain in the number means the sensor response
result
00 Success FF Failure
0X0B
Setting communication
baud rate command
68 05 00 0B 02 12
Data domain（1byte）
Baud rate：default 02: 9600
00 means 9600
01 means 9600
02 means 9600
03 means 19200
04 means 38400
05 means 115200
0X8B
Sensor answer reply command
E.g: 68 05 00 8B 00 90
Data domain（1byte）
Data domain in the number means the sensor response
result
00 Success FF Failure
0X0F
Setting module address
command
68 05 00 0F 01 15
Data domain（1byte）
XX module address, address from 00 to EF range
Note: Our products have a unified address: FF, If forgot
the set address when operating ,can use the FF
address to operate the product, still normal response.
0X8F
Sensor answer reply command
E.g: 68 05 00 8F 94
Data domain（1byte）
Data domain in the number means the sensor response
result
00 Success FF Failure
0X0C
Setting angle output mode
68 05 00 0C 00 11
Data domain（1byte）
00：answer reply mode 01：Auto output mode
Default : answer reply mode
0X8C
Sensor answer reply command
E.g: 68 05 00 8C 00 91
Data domain（1byte）,
Data domain in the number means the sensor response
result
00 Success FF Failure
0X2A
Setting angle output mode
68 05 00 2A 00 2F
Data domain（1byte）
00：Horizontal mounting measurement
01：Vertical mounting measurement（connector down）
Factory default：Horizontal mounting measurement
Horizontal mounting mode: mounting the compass horizontally, the roll and pitch angle output 0
Vertical mounting mode: mounting the compass vertically，the roll and pitch angle output 0
0XAA
Sensor answer reply command
E.g: 68 05 00 AA 00 AF
Data domain（1byte）,
Data domain in the number means the sensor response
result
00 Success FF Failure
0X41
Query mounting mode command
68 04 00 41 45
Data domain（0byte）
0XC1
Sensor answer reply command
E.g: 68 05 00 C1 00 C6
Data domain（1byte）
Data domain in the number means the sensor response
result
00 Horizontal mounting mode 01 Vertical mounting
mode

HCM705B-High Accuracy Gyro Compass
0X42
Query mounting mode command
68 04 00 42 46
Data domain（0byte）
0XC2
Sensor answer reply command
E.g: 68 05 00 C2 00 C7
Data domain（1byte）
Data domain in the number means the sensor response
result
00：answer reply mode 01：Auto output mode
0X43
Set manual calibration mode
command
68 04 00 43 47
Data domain（0byte）
0XC3
Sensor answer reply command
E.g: 68 05 00 C3 00 C8
Data domain（1byte）,
Data domain in the number means the sensor response
result
00 Success FF Failure
0X44
Set auto calibration mode
command
68 04 00 44 48
Data domain（0byte）
0XC4
Sensor answer reply command
E.g: 68 05 00 C4 00 C9
Data domain（1byte）,
Data domain in the number means the sensor response
result
00 Success FF Failure
0X45
manual calibration mode
command
68 04 00 45 49
Data domian（0byte）
Each node must send one time
0X88
Sensor answer reply command
68 05 00 88 xx cs
Data domain（1byte）,
Data domain in the number means the sensor response
result xx=0~18
00：0 point，01：1 point，02：2 points … 0F：15 points
0X46
Set auto calibration mode
68 05 00 46 00 4B
Data domain（1byte）
00：compass mode 01：AHRS mode
02：MIX Mixture mode
0XC6
Sensor answer reply command
E.g:68 05 00 C6 00 CB
Data domain（1byte）,
Data domain in the number means the sensor response
result
00 Success FF Failure
0X4F
Set auto calibration mode
command
68 04 00 4F 53
Data domain（1byte）
0XCF
Sensor answer reply command
E.g: 68 05 00 CF 00 54
Data domain（1byte）,
Data domain in the number means the sensor response
result
00：compass mode 01：AHRS mode
02：MIX Mixture mode
Default is compass mode
When test has the magnetic interference automatically
switch to the AHRS mode, non-magnetic interference is
detected, then switch to the compass mode
0X47
When calibration if output HPR
data command
Data domain（1byte）
00：Calibration no HPR data output

HCM705B-High Accuracy Gyro Compass
68 05 00 47 00 4C
01：Calibration has HPR data output
0XC7
Sensor answer reply command
E.g: 68 05 00 C7 00 CC
Data domain（1byte）,
Data domain in the number means the sensor response
result
00 Success FF Failure
0X48
Choose specific parameters
command（this command usually
don’t need customers operation ）
E.g：68 07 00 48 02 05 18 6E
Choose HEADING and PITCH
Data domain（1-10byte）
Byte4 : Choose the number of parameters，BYTE5~BYTE
14: Parameter ID，number optional。
05: heading 18H:PITCH 19H:ROLL
15H:AccelX 16H:AccelY 17H: AccelZ
1BH:MAGX 1CH:MAGY 1DH:MAGZ
4AH:GyroX 4BH:GyroY 4BH:GyroZ
0XC8
Sensor answer reply command
E.g: 68 05 00 C8 00 CC
Data domain（1byte）,
Data domain in the number means the sensor response
result
00 Success FF Failure
0X14
Read specific parameter data
command ( this command can be
used after OX48 command be
used )
68 04 00 14 18
Data domain（0byte）
0X94
Sensor answer reply command
E.g: 68 YY 00 94 XX ID1 DA1
DA2 DA3 DA4 ID2 DB1 DB2
DB3 DB4 .... CE
Data domain（5-46byte）,
Data domain in the number means the sensor response
result
BYTE4: XX ; Read the number of parameter，
BYTE5:corresponding the paramterID number。
ParameterID number as below：
05: heading 18H:PITCH 19H:ROLL
15H:AccelX 16H:AccelY 17H: AccelZ
1BH:MAGX 1CH:MAGY 1DH:MAGZ
4AH:GyroX 4BH:GyroY 4BH:GyroZ
DA1,DA2,DA3,DA4 is FLOAT 32 the big end of data
storage mode
。ParameterID（1BYTE）+ Floating-point number
data(4BYTES) indicate one group number.
0X49
The reference magnetic reset
command
68 04 00 49 4D
Data domain（0byte）
0XC9
Sensor answer reply command
E.g:68 05 00 C9 00 CE
Data domain（1byte）,
Data domain in the number means the sensor response
result
00 Success FF Failure
0X4B
Module reset command
68 04 00 4B 4F
Data domain（0byte）
The module to reset
0XCB
Sensor answer reply command
例:68 05 00 CB 00 CE
Data domain（1byte）,
Data domain in the number means the sensor response
result
00 Success FF Failure

HCM705B-High Accuracy Gyro Compass
0X05
Set relative ZERO command
68 05 00 05 00 0A
Data domain（1byte）
00：Cancel relative ZERO enter absolute ZERO
01：Set relative ZERO
0X85
Sensor answer reply command
E.:68 05 00 85 00 8A
Data domain（1byte）,
Data domain in the number means the sensor response
result
00 Success FF Failure
0X50
Set the geomagnetic threshold
judgment command
68 06 00 50 24 16 CS
Data domain（2byte）
MAX(BYTE4) ：AB/100 ,E.g 24 ，is 24/100=0.24
MIN(BYTE5) same as above 16/100=0.16
0XD0
Sensor answer reply command
E.g: 68 05 00 D0 00 D5
Data domain（1byte）,
Data domain in the number means the sensor response
result
00 Success FF Failure

HCM705B-High Accuracy Gyro Compass
（RION Compass data forma）
一Data format：
Baud rate：(9600 , 8 data bits，1data top，No check)
二, Angle output format：
For example：
Pitch：+020.10 ° Roll：-005.25°
Heading:180.00°
68 0D 00 84 00 20 10 10 05 25 01 80 00 7C
More production information please visit RION’s official website :www.rion-tech.net
（All Products are subject to change or update without notice.）
Prefix,Fixed68
Length
data,Fixed “0D”
Sensor address,
Default is “00”
Command
word,Fixed”84”
Pitch angle :
The first byte is the sign bit, 00 is
positive angle , 10 is negative angle .
The second byte is the integer bit, Is
compressed BCD code.
The third byte is decimal bytes,
Is compressed BCD code .
Roll Angle ：
Format same as pitch
The last byte is the sum of
all previous data and, If
carry ,Get low data.
Heading angle :
The first byte is low for the azimuth Angle of a one
hundred - bit integer，High byte is plus or minus，
“0”is positive，heading no negative
The second byte of azimuth bits, 10 integers, Is
compressed BCD code.
The third byte is Angle of decimal places,is
compressed BCD code.

HCM705B-High Accuracy Gyro Compass