1.Product Features
1. Through two-axis magnetoresistive sensor measures plane Earth's magnetic field, and translates the measurements into heading information.
2. High-speed and high-precision A / D conversion. The accuracy of magnetic field measurement is 100μGuass.
3. Embedded microprocessors calculate the angle between sensor and Magnetic North.
4. Operating temperature is -40℃to+85℃. Storage temperature is -55℃to+100℃.
2. Specifications
1. Heading output
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Response rate
|
3Hz
|
|
Accuracy
|
±1°
|
|
Resolution
|
±0.2°
|
|
Repeatability
|
±0.4°
|
2. Other Parameters
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Magnetic field measurement range
|
0.1Guass to 3Guass
|
|
Magnetic interference(Max)
|
20Guass
|
|
Supply Voltage
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+5VDC or 9-12VDC(Only choose a model and not compatible)
|
|
Current
|
50MA
|
|
Size
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Φ 35mm×5mm or Φ 50mm×5mm
|
|
Limit of operating temperature
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-50℃to+85℃
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3. FNN output is RS-232 data format, "9600, n, 8, 1." Each frames output 16 decimal numbers of 20 byte.
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Byte position
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Data Types
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Data content
|
|
1
|
Single byte 16 decimal numbers
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“0xaa” Header
|
|
2 3
|
Reservations
|
|
|
3 4
|
Single byte 16 decimal numbers
|
Show implementation of the command
|
|
5 6
|
Reservations
|
|
|
7 8
|
Reservations
|
|
|
9 10
|
Reservations
|
|
|
11 12
|
Double byte signed integers
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Magnetic field intensity of X
|
|
13 14
|
Double byte signed integers
|
Magnetic field intensity of Y
|
|
15 16
|
Reservations
|
|
|
17 18
|
Double- byte unsigned integers
|
the angle between sensor and Magnetic North.( Integers/100)
|
|
19
|
Reservations
|
|
|
20
|
Single byte
|
The above data checksum
|
5. Command Table
|
|
Commands
|
Meaning
|
|
1
|
0xf5
|
Start compass calibration
|
|
2
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0xf8
|
Stop compass calibration
|
|
3
|
0xf7
|
Save data
|
|
4
|
0xa5
|
Allow to Calibrate Magnetic North
|
|
5
|
0xe5
|
Calibrate Magnetic North
|
|
6
|
0xe8
|
Cancel Magnetic North calibration
|
Explanation of command
FNN compass provides users with the six commands. Compass after receiving the command, will show implementation of the command at the fourth byte, if the show is the same with the command, means the command have been already implemented, if the show is “0xee”, means the command can not be implemented.
(1) Compass Calibration: 0xf5, 0xf8, 0xf7
Send 0xf5 and rotate the compass slowly, rotational range exceed 360 degrees (the compass’s pitch range do not exceed 1 degree).Send 0xf8 to stop compass calibration. Send 0xf7 to save the date of calibration.
(2) Calibrate Magnetic North: 0xa5, 0xe8, 0xe5
Send 0xa5 to enter into the state of calibrating Magnetic North, send 0xe8 to cancel previous setting, send 0xe5 to set the current direction as the zero-angle.
3 Pin diagram
1. 12V Interface
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Pin
|
Name
|
Description
|
|
1
|
+12V
|
Power input
|
|
2
|
GND
|
Power ground
|
|
3
|
TXO
|
RS-232 transmit out
|
|
4
|
RXI
|
RS-232 receive in
|
|
5
|
GND
|
Signal ground
|
|
6
|
PRO
|
Linking Ban
|
2. 5V Interface
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Pin
|
Name
|
Description
|
|
1
|
+5V
|
Power input
|
|
2
|
GND
|
Power ground
|
