RS485 Wind Vane Direction Sensor (แท้จาก DFRobot)

The wind direction sensor is a professional meteorological instrument used to measure horizontal wind direction. It integrates a hall sensor inside. The shell and weather vane is made of aluminum alloy material and uses special mold precision die casting process, featuring small dimension tolerance and high surface accuracy. The sensor internal circuit is protected, which makes the sensor have the properties of high strength, weather resistance, anti-corrosion, and waterproof. The cable connector adopts a corrosion-resistant military plug that ensures the long service life of the product.

A low-inertia wind vane is used to sense the wind direction. When the wind direction changes, the tail wing rotates to drive the axle magnet to rotate through the shaft, thereby obtaining accurate wind direction information. It can detect the 16 azimuths' natural wind directions. This high-cost performance sensor can be widely used in meteorology, ocean, environment, airports, ports, laboratories, industry, agriculture, and transportation.

FEATURES 

• High measurement accuracy, fast response, good interchangeability
• Easy to install and operate
• High sensitivity: start-up wind speed≤0.3m/s
• Suitable for various harsh environments, high wind resistance

SPECIFICATION 

• Measuring Range: 16 directions
• Start-up Wind Speed: 0.3m/s
• Lead Length: 2.5m/98.43”
• Power Voltage: 7-24V
• Communication Protocol: RS485 interface Modbus protocol

 DOCUMENTS 

• Product wiki

SHIPPING LIST 

• RS485 Wind Direction Transmitter x1
• 2.5m Wire x1

Tutorial

1. Wire Color Description

2. Installation Instruction

The white dot on the sensor must face true north in installation.

3. Modbus Protocol

• The default communication parameters are: baud rate 9600bps, one start bit, 8 data bits, no parity, and one stop bit.

• Modbus Register

• Modbus Register Parameter Instruction

Modbus address, can be set to 0-255. Use 0 address to set any address, after setting, you need to re-power on and restart the module to make this address take effect

• Example

1. Read register 0x0000, that is the measuring value of the wind direction

Host query frame (hexadecimal): 02 03 00 00 00 01 84 39 (8byt)

Slave response frame (hexadecimal): 02 03 02 00 03 BC 45 (7byt)

16 azimuth value=00 03=3, corresponding to the table below to get the azimuth as northeast by east.

2. Modify register 0x1000, which is the Modbus slave address (ADDRESS)

Slave response frame (hexadecimal): 00 10 10 00 00 01 04 D8 (7byt), that is, the modification is successful. After setting, you need to re-power on and restart the transmitter to make this address take effect.

Using in Raspberry Pi

1. Connection

Here USB to RS485 Module is used.

2. Install libraries and download routines

Type the following commands in the terminal one by one

cd /tmp
wget https://project-downloads.drogon.net/wiringpi-latest.deb //Download wiringpi library
sudo dpkg -i wiringpi-latest.deb //Install wiringpi library
cd ..... //Enter the content you want to save file in
git clone https://github.com/DFRobotdl/RS485_Wind_Direction_Transmitter.git //Download program in github
cd RS485_Wind_Direction_Transmitter/

3. API Function List

/**
@brief initialize serial port
@param device Address of serial port，In Linux, it is the directory where the device is located.
@return Return 1 for initialization failure, and return 0 for initialization success
*/
unsigned char Init(char *device);

/**
@brief Modify address
@param Address1 For the current address, you can set any address with 0 address
@param Address2 The modified address.
@return A return value of 1 indicates success, and a return value of 0 indicates failure
*/
unsigned char ModifyAddress(unsigned char Address1, unsigned char Address2);

/**
@brief Read wind direction
@param Address The address where you want to read the data
@return The return value ≥0 indicates successful reading, the return value is the wind direction corresponding to the following table, and the return value is -1 indicates failed reading
Return the value to the direction correspondence table
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
| value | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 |
|-----------|-------|-----------|-----------|-----------|------|-----------|-----------|-----------|-------|-----------|-----------|-----------|------|-----------|-----------|-----------|
| Direction | North | Northeast | Northeast | Northeast | East | Southeast | Southeast | Southeast | South | Southwest | Southwest | Southwest | West | Northwest | Northwest | Northwest |
| | | by north | | by east | | by east | | by south | | by south | | by west | | by west | | by north |
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

*/
int readWindDirection(unsigned char Address);

4. Check the device

Type this in the terminal:

 sudo ls -l /dev

Find out the device you just connected in.

5. Open the previously downloaded min.c file, change the device port in the program to the actual one and save it

6. Use the terminal to open the folder where the program is located, compile and run

gcc -Wall -lwiringPi -o Wind_Direction *.c
sudo ./Wind_Direction

You can see the accurate wind direction information