Renke RS-FSJT-N01 Wind speed anemometer

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:

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

Advanced settings

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 device modbus address is stored in register 2000. To change it, you can use the following temporary ESPHome configuration:

sensor:
  - platform: modbus_controller
    modbus_controller_id: wind_speed_meter
    name: "Device current address"
    register_type: read
    address: 2000
    value_type: U_WORD

number:
  - platform: modbus_controller
    modbus_controller_id: wind_speed_meter
    name: "Device new address"
    address: 2000
    register_type: holding
    value_type: U_WORD
    mode: box

The new entered value will be sent to the device immediately, causing it to become offline. You need to change the address value in the corresponding modbus_controller entry to the value you just used.

Alternatively, 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 device address to something else (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.

The device baud rate is configured in register 2001 using an ID:

Baud rate	ID
2400	0
4800	1
9600	2
19200	3
28400	4
57600	5
115200	6

To change it, you can use the following temporary ESPHome configuration:

sensor:
  - platform: modbus_controller
    modbus_controller_id: wind_speed_meter
    name: "Device current baud ID"
    register_type: read
    address: 2001
    value_type: U_WORD

number:
  - platform: modbus_controller
    modbus_controller_id: wind_speed_meter
    name: "Device new baud ID"
    address: 2001
    register_type: holding
    value_type: U_WORD
    mode: box

The new entered value will be sent to the device immediately, causing it to become offline. You need to change the baud_rate value in the corresponding uart entry to the value you just entered.

To avoid accidental address changes, it's recommended to comment out the above sections, then reflash node with the new settings. Only have one device connected at the time working with these settings.