ESPHome ModBus decoding

ESPHome
1

hello,
I want to retrieve data from an Imeon inverter with ESPHome32 by the Modbus rtu protocol, the manufacturer has provided me with the documentation.
with this one I can see my frames and view the data with the software "Qmodmaster’

two examples:
with manufacturer doc > frames sent and received by qmodmaster and ESPHome logs
serial number recovery

1 serial number recovery

test
test1053×221 19.3 KB 

Frames I retrieve with qmodmaster
[RTU]>Tx > 18:45:38:609 - 01 03 00 01 00 04 15 C9
[RTU]>Rx > 18:45:38:857 - 01 03 08 00 00 50 5D 2D 3C 7F EF DC 96

Frames by ESPHome with custom_command
[21:51:27][D][uart_debug:114]: >>> 01:03:00:01:00:04:15:C9:00
[21:51:27][D][modbus_controller:032]: Modbus command to device=1 register=0xE828 countdown=0 no response received - removed from send queue

Voltage recovery:

test2
test21024×101 9.62 KB 

Frames I retrieve with qmodmaster
[RTU]>Tx > 18:46:04:110 - 01 03 01 00 00 01 85 F6
[RTU]>Rx > 18:46:04:110 - 01 03 02 09 41 7E 24

Frames by ESPHome: with custom_command
[14:35:01][D][uart_debug:114]: >>> 01:03:01:00:00:01:85:F6:00
[14:35:01][D][modbus_controller:032]: Modbus command to device=1 register=0xAB13 countdown=0 no response received - removed from send queue

we see that ESPHome sends: 00 more at the end of the frame
I don’t know if this is normal!

here is my ESPHome code:

uart:
  id: mod_bus
  tx_pin: 17
  rx_pin: 16
  
  baud_rate: 9600
  stop_bits: 1
  debug:
  
modbus:
  
  flow_control_pin: 5
  id: modbus1

modbus_controller:
  - id: imeon
    ## the Modbus device addr
    address: 0x01
    modbus_id: modbus1
    setup_priority: -10

sensor:
  - platform: modbus_controller
    modbus_controller_id: imeon
    name: "serial number"
    id: serial_number
    custom_command: [ 0x01, 0x03, 0x00, 0x01, 0x00, 0x04, 0x15 ]
    value_type: U_QWORD_R
    
  - platform: modbus_controller
    modbus_controller_id: imeon
    name: "Voltage"
    id: voltage
    custom_command: [ 0x01, 0x03, 0x01, 0x00, 0x00, 0x01, 0x85 ]
    value_type: U_WORD
    unit_of_measurement: V

value_type: I don’t know if it’s good but somehow I don’t get a response from the inverter
I hope I was clear in my request.
Thank you for your answers

be indulgent towards my English I do the French / English translation with google translate

2

Hi, I just solved the same error (no response received - removed from send queue) and finally changing the send_wait_time parameter helped me.

modbus:
  send_wait_time: 500ms
  flow_control_pin: 5
  id: modbus1

But your case will probably be different. I think you’re sending the modbus query the wrong way.
Do you realy need to send custom_command? I’ve modified the code I’m using, so hopefully it will work for you.

sensor:
  - platform: modbus_controller
    modbus_controller_id: imeon
    id: voltage
    name: "AC Grid voltage"
    address: 0x0100
    unit_of_measurement: "V"
    icon: mdi:sine-wave
    register_type: holding #or register_type: read
    value_type: U_WORD
    accuracy_decimals: 1
    filters:
      - multiply: 0.01

Also look at the modbus specification in esphome.

3

Hello;
Thank you for your reply
I try your code and let you know
thank you

1 Like
4

Hello,
your code works
thank you

5

Is it possible to recive data from Modbus TCP with esphome?

6

Hi Imornet,

It is possible to share with me the Modbus rtu protocol documentation that IMEON provided you ?

With best regards,
Dan