ESPHOME Modbus question

ESPHome
1

Hi everybody,
i have a simple question i guess, i have a SDM120M and i like to greb the information from that device with a esp32.
what is the best converter i can use?
MAX385 or this one TTL RS485 Adapter 485 UART Seriell 3.3V 5 Volt Level Konverter Modul Arduino ... | eBay
if i use the MAX385 i need the RX and TX pin but where i have to connect the both other pins to and how do i have to set this up in esphome?
thanks in advanced
matze

2

If you use one microchip, then you will also have to control the direction of data transfer.
It is better to use modules, they are still often and with galvanic isolation.
To communicate with the device, you need to know the addresses of the registers.
“Please contact us for the detailed Modbus/M-Bus communicaon protocol.
[email protected]”
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But unfortunately the modbus components integrated into esphome do not work quite correctly, and on this forum they could not answer my question.

3

Flow control pin

Just as example:

uart:

  id: modbus_serial
  rx_pin: 19
  tx_pin: 18
  baud_rate: 9600
  stop_bits: 1

modbus:

  #flow_control_pin: 5
  id: modbus1
  uart_id: modbus_serial

modbus_controller:

  - id: edpbox
    update_interval: 31s
    address: 0x1
    command_throttle: 150ms
    setup_priority: -10

Maybe this help: