Modbus RTU RS485 to ESP8266 autonics MT4W

Projects Programming
1

I have problem with reading data from autonics mt4w through rs-485. Ive been following every step that i watched from youtube edc. And keep failing to read either holding register or input register. This is my code:

#include <ModbusMaster.h>

#define MT4W_ADDRESS 1 // Set according to your MT4W Modbus address
#define RX_PIN D2 // GPIO pin connected to RS485 RX
#define TX_PIN D3 // GPIO pin connected to RS485 TX

ModbusMaster node;

void setup() {
Serial.begin(9600);
Serial.println("Starting Modbus RTU with ESP8266");

// Initialize Modbus communication with MT4W
node.begin(MT4W_ADDRESS, Serial);
}

void loop() {
uint8_t result;
uint16_t measuredValue;

// Read "Measured value" from holding register 30001 (0x0000)
result = node.readHoldingRegisters(0x0000, 1); // Register 30001 in hex is 0x0000

if (result == node.ku8MBSuccess) {
measuredValue = node.getResponseBuffer(0);
Serial.print("Measured Value: ");
Serial.println(measuredValue);
} else {
Serial.print("Error reading register: ");
Serial.println(result);
}

delay(1000); // Polling delay
}

Does anyone has experienced to help me to read value from autonics. Thanks

IMG_20241106_194051_500
IMG_20241106_194051_5001920×2560 244 KB

2

Have you tried to test communication mt4w via software modbus poll with modul RS485 to ttl?

3

please follow the forum how to and post your code in code tags.
It is described here:

You can edit your first post and put the code in code tags.

Error Code 226 (in hex 0xE2) means the device is not responding - you might have a wrong connection.

provide following missing information:

  • upload a schematic so we can see how you want to connected your components
  • upload pictures so we can see what you have connected in reality
  • link to the datasheet of the "MT4W" so we can check the supported modbus functions and addresses
4

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