Suggestions for troubleshooting RS485-Modbus sensor reporting "Unknown"

This is my first attempt to connect a RS485-Modbus sensor using ESPHome (8266+485 to serial UART. I had the two sensors I am playing around with (wind direction and wind speed) connected and working with ModScan32, so I know they are working. However, when connecting using the hardware listed above, in Home Assistant I get “Unknown.”

For the specifics (just trying with one sensor right now):

The settings that worked with ModScan32 were:

Device details:
Device is: 1
Device address: 0001
Length: 1
MODBUS Point Type: 03: HOLDING REGISTER
Connection details:

  • Baud rate: 4800
  • Word Length: 8
  • Parity: None
  • Stop bits: 1

The pertinent yaml code that I am using:

uart:
  id: mod_bus
  tx_pin: GPIO01
  rx_pin: GPIO03
  baud_rate: 4800
  stop_bits: 1

modbus:
  id: modbus1

modbus_controller:
  id: sensor1
  address: 0x1
  modbus_id: modbus1

sensor:
  - platform: modbus_controller
    modbus_controller_id: sensor1
    id: sensor_1_data
    address: 1
    name: "Sensor 1"
    register_type: holding
    value_type: U_WORD

The error I get in the logs is:
modbus_controller:040]: Modbus command to device=1 register=0x01 countdown=0 no response received - removed from send queue

Appreciate any suggestions on what I should look at to help troubleshoot this. I don’t know where to start. If additional info is needed to help troubleshoot, please let me know.

Thanks!!