I try to communicate with 2 RS485 sensors (pH and EC) but i have some troubles with my code. First, i tried to get datas from just one:

The function in charge of request sending:

String GET_probe(String probe){

if(probe == "pH"){
Serial.println("Sending request pH...");
digitalWrite(modbusModuleRE, RS485Transmit);  // Init Transceiver
digitalWrite(modbusModuleDE, RS485Transmit);  // Init Transceiver
byte  RTUrequest[] = {0x00, 0x03, 0x00, 0x00, 0x00, 0x01, 0x85, 0xDB};
RS485Serial.write(RTUrequest, sizeof(RTUrequest));
}

if(probe == "EC"){
Serial.println("Sending request EC...");          

digitalWrite(modbusModuleRE, RS485Transmit);  // Init Transceiver
digitalWrite(modbusModuleDE, RS485Transmit);  // Init Transceiver
byte  RTUrequest[] = {0x01, 0x03, 0x00, 0x00, 0x00, 0x02, 0xC4, 0x0B};
RS485Serial.write(RTUrequest, sizeof(RTUrequest));  
}

RS485Serial.flush();
RS485Serial.listen();
}

The function in charge of reading sensor's answer:

void ReadRx() {
     digitalWrite(modbusModuleRE, RS485Receive);
     digitalWrite(modbusModuleDE, RS485Receive);
     if(RS485Serial.available()) {
     Serial.print("Answer: ");
      for(int i=0; i<7; i++){  
          String myByte = String(RS485Serial.read(), HEX);// Read the byte

          if (myByte.length() == 1)
          {
            myByte = "0"+myByte;
          }
          modbusHexBuffer[i] = myByte;

          Serial.print(myByte);
          Serial.print(" "); 
      }
      Serial.println();
    }
   }

And the loop, sending the request each 5s:

void loop(){

  static uint32_t ts = millis();

  if (millis() - ts >= 5000) {
      ts = millis();
      GET_probe("pH");
  }

ReadRx();
}

The loop runs fine once and fails at 2nd as shown in terminal. Can you tell me why and help me to fix it?

Sending request pH...
Answer: 00 03 02 05 78 86 f6 
Sending request pH...

I try to communicate with 2 RS485 sensors (pH and EC), but I have some troubles with my code. First, I tried to get data from just one:

The function in charge of request sending:

String GET_probe(String probe){

if(probe == "pH"){
Serial.println("Sending request pH...");
digitalWrite(modbusModuleRE, RS485Transmit);  // Init Transceiver
digitalWrite(modbusModuleDE, RS485Transmit);  // Init Transceiver
byte  RTUrequest[] = {0x00, 0x03, 0x00, 0x00, 0x00, 0x01, 0x85, 0xDB};
RS485Serial.write(RTUrequest, sizeof(RTUrequest));
}

if(probe == "EC"){
Serial.println("Sending request EC...");          

digitalWrite(modbusModuleRE, RS485Transmit);  // Init Transceiver
digitalWrite(modbusModuleDE, RS485Transmit);  // Init Transceiver
byte  RTUrequest[] = {0x01, 0x03, 0x00, 0x00, 0x00, 0x02, 0xC4, 0x0B};
RS485Serial.write(RTUrequest, sizeof(RTUrequest));  
}

RS485Serial.flush();
RS485Serial.listen();
}

The function in charge of reading sensor's answer:

void ReadRx() {
     digitalWrite(modbusModuleRE, RS485Receive);
     digitalWrite(modbusModuleDE, RS485Receive);
     if(RS485Serial.available()) {
     Serial.print("Answer: ");
      for(int i=0; i<7; i++){  
          String myByte = String(RS485Serial.read(), HEX);// Read the byte

          if (myByte.length() == 1)
          {
            myByte = "0"+myByte;
          }
          modbusHexBuffer[i] = myByte;

          Serial.print(myByte);
          Serial.print(" "); 
      }
      Serial.println();
    }
   }

And the loop, sending the request each 5s:

void loop(){

  static uint32_t ts = millis();

  if (millis() - ts >= 5000) {
      ts = millis();
      GET_probe("pH");
  }

ReadRx();
}

The loop runs fine once and fails the second time, as shown in terminal. Can you tell me why and help me to fix it?

Sending request pH...
Answer: 00 03 02 05 78 86 f6 
Sending request pH...