Renke RS-FSJT-N01 Wind speed anemometer

Device Type: sensor

Electrical Standard: global

General Notes

The Renke RS-FSJT-N01 Wind speed anemometer is sold in four versions:

• RS485 digital ModBUS output
• 0-5V analog voltage output
• 0-10V analog voltage output
• 4-20mA analog current output

Parameters:

• Measurement range: 0~30m/s, resolution 0.1m/s, accuracy ± 0.3m/s
• Starting wind speed: 0.5m/s
• DC power supply: 10~30V DC

Configuration presented here is for the RS485 digital ModBUS version.

Wiring

The cable coming out through the bottom of the unit has the folling pinout:

• Brown: positive power supply
• Black: negative power supply and GND
• Green: RS485-A
• Blue: RS485-B

ModBUS Parameters

Wire up a an RS485 transceiver to an ESP32 to interface with the device using ESPHome's Modbus Component.

Connection parameters:

• Baud Rate: 4800 (default), supports 2400 and 9600
• Data bit length: 8
• Parity check: None
• Stop bit: 1
• Device address: 1
• Register address for speed value: 0
• Register data type: U_WORD, multiplied by 10

Basic Configuration

Slow winds blow in small bursts, so it's recommended to average measurements to have a better overview of the wind condition. That's why we're reading out the measurement every second, and apply a filter to the sensor, taking the maximum blow speed of 5 measurements, averaging them every minute:

Copy
esphome:
  name: example-device
  friendly_name: Example Device
    
# OTA flashing
ota:
  - platform: esphome

wifi: # Your Wifi network details
  
# Enable fallback hotspot in case wifi connection fails  
  ap:

# Enabling the logging component
logger:

# Enable Home Assistant API
api:

# Enable the captive portal
captive_portal:

uart:
  rx_pin: GPIOXX
  tx_pin: GPIOXX
  baud_rate: 4800

modbus:
  id: modbus1

modbus_controller:
  - id: wind_speed_meter
    address: 1
    modbus_id: modbus1
    setup_priority: -10
    command_throttle: 200ms
    update_interval: 1s

sensor:
  - platform: modbus_controller
    modbus_controller_id: wind_speed_meter
    name: "Wind speed"
    device_class: wind_speed
    register_type: read
    address: 0
    unit_of_measurement: "m/s"
    value_type: U_WORD
    accuracy_decimals: 1
    filters:
      - multiply: 0.1
      - max:
          window_size: 5
          send_every: 5
      - exponential_moving_average:
          alpha: 0.1
          send_every: 12

Note that the sensor is by default set to ModBUS address 1, so out of the box it's not possible to connect it together with another one (like a RS-FXJT-N01 wind direction sensor) to the same ESP UART.

The manufacturer offers a helper application for Windows, called 485 Parameter Configuration Tool. The sensor can be connected to the PC with a USB-to-RS485 adapter, and the configuration tool makes it easily possible to change the modbus address to something else, eg. 2 (just type it in the Addr box and press Setup button).

After that it becomes possible to simply connect the sensors in parrallel on the same cable, to a single RS485-TTL transceiver attached to a single UART on the ESP (you need to change the address value in the corresponding modbus_controller entry in the config).