IFB_dev/FC_InferfaceBoard/RS485.ino

// Sample communication Code for RS 485 Shield with Arduino Mega 2560
#define RS485_OE_1 22 //RS485 CH#1 Output Enable => pin 22 for CH#1
#define Snd_485 HIGH
#define Rcv_485 LOW

#define MC9_10_PV "10DRS,08,0001CB"
#define MC9_10_SV "10DRS,08,0011CC"

void RS485_setup(){
  Serial1.setTimeout(300);
  Serial1.begin(9600);
  pinMode(RS485_OE_1, OUTPUT);
  delay(10);
  digitalWrite(RS485_OE_1, Rcv_485);
}

void send_485(){
  if(!Wait_485){
    String message = read_buff(Buff_485_Wr);
    // Send request to return pv data
    //Serial.println(Buff_485_Wr);
    //Serial.print(message);
    //Serial.print("   :   ");
    if(message != ""){
      latest_sent_msg = message;
      message += "\r\n";
      digitalWrite(RS485_OE_1, Snd_485); delay(5);
      Serial1.print(message);
      returnTime = millis();
      Serial1.flush();
      digitalWrite(RS485_OE_1, Rcv_485); delay(5);

      Wait_485 = true;
      Wait_485_cnt = 0;
    }
    else{
      //Serial.println("Free");
    }
    
  }
  
}

int read_485(){
  // Timeout code
  if(Wait_485){
    Wait_485_cnt++;
    if(Wait_485_cnt > 200){ // Timeout = periodic(100ms) x 200 = 2 sec
      Serial.println("485 not responced... (Timeout)");
      latest_sent_msg = "";
      Wait_485 = false;
      Wait_485_cnt = 0;
      numOf485--;
      return 0;
    }
  }
  // Receive pv data
  while(Wait_485 && (Serial1.available() > 0)) {
    char c = Serial1.read();    
    write_buff_c(Buff_485_Rd, c);
  }

  String message = read_buff(Buff_485_Rd);
  if(message != ""){
    
    int addr;
    String mode;
    int data[8];
    int crc;
    numOf485--;
    //message.replace("\r\n","");
    //Serial.println(message);
    if (parseMessage(message, addr, mode, data, crc)) {

      if(latest_sent_msg == MC9_10_PV){
        for(int i = 0 ; i < Size_PV ; i++){
          Values_10_PV[i] = data[i];
        }
      }
      if(latest_sent_msg == MC9_10_SV){
        for(int i = 0 ; i < Size_SV ; i++){
          Values_10_SV[i] = data[i];
        }
      }
    } else {
        // OK가 아닌 경우 또는 파싱 오류가 발생한 경우
        Serial.println("error 485 read");
    }
    Wait_485 = false;
    Wait_485_cnt = 0;
  }
  return 1;
}

int parseMessage(const String& message, int& addr, String& mode, int data[8], int& crc) {
    char addrC[3], modeC[4], statusC[3];
    int dataC[8], crcC;

    if (message[0] == '\x02') {
      message = message.substring(1);
    }

    int ret = sscanf(message.c_str(), "%2s%3s,%2s,%4x,%4x,%4x,%4x,%4x,%4x,%4x,%4x%2x", 
        addrC, modeC, statusC, &dataC[0], &dataC[1], &dataC[2], &dataC[3], &dataC[4], &dataC[5], &dataC[6], &dataC[7], &crcC);


    if (strcmp(statusC, "OK") != 0 || ret != 12) {
        // 오류 처리
        return 0;
    }
    
    // 복사
    addr = atoi(addrC);
    mode = String(modeC);
    for (int i = 0; i < 8; i++) {
        data[i] = dataC[i];
    }
    crc = crcC;

    return 1;
}