I’m try to get data from rs485 is not work please advise to me.

1.  Try to connect PC usb485 to DY-MD02 is work.
    Send command “AUTO” or “READ”

2.  Try to Arduino rs485 shield to DY-MD02 is not work.
    Send command “AUTO”

my code

''''

char command[4] = {'A', 'U', 'T', 'O'};

int n = sizeof(command)/sizeof(command[0]);   // Number of elements in an array

String incoming = "";   // for incoming serial string data

void setup()

{

      // initialize serial ports
      Serial.begin(9600);
      pinMode(EN,OUTPUT);
      digitalWrite(EN,HIGH); //Enable high, RS485 shield waiting to transmit data
      Serial.write(command,n); //Test send command Auto,Read to RS485
      delay(500);
}

void loop()

{
           
      String temp;
      digitalWrite(EN,LOW); //Enable low, RS485 shield waiting to receive data
    
      while(Serial.available() > 0 )
      {
          temp=Serial.read();
          Serial.println(temp);
          delay(1000); //Delay for some time, waiting for data transmitted
      }

}

''''

if change code to = Serial.readString() not show anything.

please help me Thank

I’m try to get data from rs485 is not work please advise to me.

1.  Try to connect PC usb485 to DY-MD02 is work.
    Send command “AUTO” or “READ”

2.  Try to Arduino rs485 shield to DY-MD02 is not work.
    Send command “AUTO”

my code

''''

char command[4] = {'A', 'U', 'T', 'O'};

int n = sizeof(command)/sizeof(command[0]);   // Number of elements in an array

String incoming = "";   // for incoming serial string data

void setup()

{

      // initialize serial ports
      Serial.begin(9600);
      pinMode(EN,OUTPUT);
      digitalWrite(EN,HIGH); //Enable high, RS485 shield waiting to transmit data
      Serial.write(command,n); //Test send command Auto,Read to RS485
      delay(500);
}

void loop()

{
           
      String temp;
      digitalWrite(EN,LOW); //Enable low, RS485 shield waiting to receive data
    
      while(Serial.available() > 0 )
      {
          temp=Serial.read();
          Serial.println(temp);
          delay(1000); //Delay for some time, waiting for data transmitted
      }

}

''''

if change code to = Serial.readString() not show anything.

please help me Thank

to Juraj

Maker tell me can connect with Arduino uno and send manual to me.

see in attach file.