Multiple slave devices

[xor3x1]

Hi, is it possible to read data from 2 different slave devices? If so how do I obtain it?
I tried with simply creating 2 nodes, each for 1 device, but I am able to read from only one device.

[miteshrabadiaaru]

The code is designed to handle multiple slave IDs and reads data from the connected sensors sequentially. If you need any help with this, feel free to let me know!

Code

// Define an array of sensor addresses
const uint8_t SENSOR_ADDRESSES[] = { 0x01, 0x02, 0x03, 0x04, 0x06, 0x07, 0x08 };  // SlaveID
const int NUM_SENSORS = sizeof(SENSOR_ADDRESSES) / sizeof(SENSOR_ADDRESSES[0]);

// ... existing code ...

void setup() {
  // ... existing setup code ...

  // Initialize ModbusMaster without specifying an address
  /* Remove this
  node.begin(0, Serial2);
  node.preTransmission(preTransmission);
  node.postTransmission(postTransmission);
  */

  // ... rest of setup code ...
}

void loop() {
  // ... existing loop code ...

    // Loop through each sensor address
    for (int i = 0; i < NUM_SENSORS; i++) {
      int currentAddress = SENSOR_ADDRESSES[i];

      // Set the current sensor address
      node.begin(currentAddress, Serial2);
      node.preTransmission(preTransmission);
      node.postTransmission(postTransmission);
      // put some delay to start proper communication
      // Half second delay
      long int waitTime = millis();
      while ((waitTime + 500) > millis()) {
      }

      Serial.print("Reading sensor at address: 0x");
      Serial.println(currentAddress, HEX);

      // Perform read operation for the current sensor
      // You'll need to adjust the register addresses and data processing for each sensor type
      uint8_t result = node.readHoldingRegisters(0x0000, 4);

      if (result == node.ku8MBSuccess) {
        // Process and publish data for the current sensor
        yourFunction(currentAddress);
      } else {
        handleReadError(currentAddress, result);
      }

      // Add a small delay between sensor reads
      delay(100);
    }

  // ... rest of your loop code ...
}


void handleReadError(uint8_t sensorAddress, uint8_t errorCode) {
  Serial.print("Failed to read from sensor at address 0x");
  Serial.print(sensorAddress, HEX);
  Serial.print(". Error code: ");
  Serial.println(errorCode, HEX);
}

// ... rest of your code ...