Communicate between multiple ESP's with RS485 Modbus

[k0cka]

I tried to look for some examples but I don't really know how to structure the code for the slaves. Could you guide me or this forum is only support for the Kincony's products?

Do you mean something like this or is there a better way? Let's say I just want to be able to control the GPIO 16 and GPIO 15, would something like this work?

ESPHome master:

Code:

uart:
  id: rs485_uart
  tx_pin: GPIO1
  rx_pin: GPIO3
  baud_rate: 9600

modbus:
  id: modbus_master
  uart_id: rs485_uart

modbus_controller:
  id: relay_controller
  modbus_id: modbus_master
  address: 1

switch:
  - platform: modbus_controller
    name: "Relay_GPIO16"
    register_type: holding
    address: 0
    modbus_controller_id: relay_controller

  - platform: modbus_controller
    name: "Relay_GPIO15"
    register_type: holding
    address: 1
    modbus_controller_id: relay_controller

Arduino code for slave:

Code:

#include <ModbusMaster.h>

#define TX_PIN 1
#define RX_PIN 3
#define MODBUS_SLAVE_ADDRESS 1

ModbusMaster node;

void setup() {
  Serial.begin(9600);
  pinMode(16, OUTPUT); // Set GPIO 16 as an output
  pinMode(15, OUTPUT); // Set GPIO 15 as an output
  node.begin(MODBUS_SLAVE_ADDRESS, Serial);
}

void loop() {
  uint8_t result = node.readHoldingRegisters(0, 1);  // Request Modbus data

  // Check if the request was successful
  if (result == node.ku8MBSuccess) {
    // Check for Modbus responses
    if (node.getResponseBuffer(0) > 1) {
      uint16_t regAddress = node.getResponseBuffer(0);  // Get the register address
      uint16_t regValue = node.getResponseBuffer(1);    // Get the value to be written to the register

      // Control GPIO 16 and GPIO 15 based on the register address
      if (regAddress == 0) {
        digitalWrite(16, regValue);  // Set GPIO 16 based on the value
      } else if (regAddress == 1) {
        digitalWrite(15, regValue);  // Set GPIO 15 based on the value
      }
    }
  }
}
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