RS485 Wind Direction Sensor/Transmitter V2 Wiki - DFRobot

Introduction

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 are made of aluminum alloy material and use 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 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 natural wind directions. This sensor with high cost performance 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, strong wind resistance

Specification

• Measuring Range: 16 directions & wind direction of 360°
• Start-up Wind Speed: 0.3m/s
• Lead Length: 2.5m/8.20"
• Power Voltage: 7-24V
• Communication Protocol: RS485 interface Modbus protocol

Dimension

User Guide

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

Indication: the wind direction measured in degrees (°) from 0° to 360°
Example: If the returned value is 02 8F (hexadecimal) = 655 (decimal) ÷ 10 = 65.5°, the degree is the angle with the true north (i.e. 0°).

Indication: the wind value of 16 directions
Example: If the returned value is 00 04 (hexadecimal, true form), the high byte of the first byte is 00, the low byte of the second byte is 04, and the measured wind direction value is (00*256+04)=4, 0 for true north and clockwise 4 for true east.

Modbus address can be set to 0-255. You can use 0 address to set any address.

• Example

1. Read the 360° wind direction angle (Modbus slave address 0x02)

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

Slave response frame (hexadecimal): 02 03 02 02 8F BC 80 (7byt)

Wind angle value = 02 8F (hex) = 655 (decimal) ÷ 10 = 65.5°, which is the angle with the true north (i.e. 0°).

2. Read the 16 wind directions (Modbus slave address 0x02)
   

Host query frame (hexadecimal): 02 03 00 01 00 01 D5 F9（8byt）

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

16 directions value = 00 03 = 3, the direction is east-northeast according to the table below.

Correspondence Table

3. Read device Modbus slave address
   

You can query the devices at any address using 0x00 address (broadcast address).
Host query frame (hexadecimal): 00 03 10 00 00 01 81 1B (8byt)

Slave response frame (hexadecimal): 00 03 02 00 15 8C D8 (7byt)

Current device Modbus slave address = 00 15 (hex), i.e. the current device Modbus slave address is 0x15.

4. Change register 0x1000, i.e. change Modbus slave address (ADDRESS)
   

Change Modbus slave address to 03
You can set the devices at any address using the 0x00 address (broadcast address).
Host query frame (hexadecimal): 00 10 10 00 00 01 02 00 03 FA 00 (11byt)

Slave response frame (hexadecimal): 00 10 10 00 00 01 04 D8 (7byt), and that indicates the modification is successful.

Tutorial

Requirements

• Hardware
  • RS485 Wind Direction Transmitter
  • Gravity: Active Isolated RS485 to UART Signal Adapter Module
  • Arduino Uno

• Software
  • Arduino IDE
  • Download and install the RS485_Wind_Direction_Transmitter_V2 Library (About how to install the library?)

Connection Diagram

Sample Code

Copy the following code and paste it to your Arduino IDE and upload it.

#include "RS485_Wind_Direction_Transmitter_V2.h"


/**
   @brief RS485_Wind_Direction_Transmitter_V2 constructor
   @param serial - serial ports for communication, supporting hard and soft serial ports
   @param rx - UART the pin for receiving data
   @param tx - UART the pin for transmitting data
*/
#if defined(ARDUINO_AVR_UNO)||defined(ESP8266)   // use soft serial port
SoftwareSerial softSerial(/*rx =*/2, /*tx =*/3);
RS485_Wind_Direction_Transmitter_V2 windDirection(/*softSerial =*/&softSerial);
#elif defined(ESP32)   // use the hard serial port with remapping pin : Serial1
RS485_Wind_Direction_Transmitter_V2 windDirection(/*hardSerial =*/&Serial1, /*rx =*/D3, /*tx =*/D2);
#else   // use the hard serial port : Serial1
RS485_Wind_Direction_Transmitter_V2 windDirection(/*hardSerial =*/&Serial1);
#endif

uint8_t Address = 0x02;

const char* Orientation[17] = {
  "North", "North-northeast", "Northeast", "East-northeast", "East", "East-southeast", "Southeast", "South-southeast", "South",
  "South-southwest", "Southwest", "West-southwest", "West", "West-northwest", "Northwest", "North-northwest", "North"
};

void setup()
{
  Serial.begin(115200);

  // Init the sensor
  while ( !( windDirection.begin() ) ) {
    Serial.println("Communication with device failed, please check connection");
    delay(3000);
  }
  Serial.println("Begin ok!");
//Change modbus slave address, and you can use 0x00 broadcast address to change it if you forgot the current address.
//  windDirection.SetSlaveAddress(/*the current modbus slave address*/0x00, /*the address after the change*/0x02);
//Get modbus slave address
//  Address = windDirection.GetSlaveAddress();
}

void loop()
{
  //Get 16 wind directions
  int Direction = windDirection.GetWindDirection(/*modbus slave address*/Address);
  //Get 360° wind direction
  float Angle = windDirection.GetWindAngle(/*modbus slave address*/Address);
  Serial.println(Orientation[Direction]);
  Serial.print(Angle); Serial.println("°");
  Serial.println();
  delay(1000);
}

Result

FAQ

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