Fröling PE1: Meine Lösung um Daten mit Arduino über RS232 Modbus RTU auszulesen (COM2)

/////////////////////////////////////////////////////////////////////////////////////////////////////
//Modbus RTU RS232 communication between Arduino Uno and Fröling PE1
//
//Author: fabulous
//
//v0.01, April 2023
//
//Arduino Uno/Seeed RS232 Shield with female SubD9 connector: pin 2 = Tx, pin 3 = Rx
//Fröling PE1 main board (FRKEM29) with male SubD9 connector (aka "COM2"): pin 2 = Rx, pin 3 = Tx

//in "Idle", both Tx pins have a voltage level /against GND on pin 5) of about -9V

#include <SoftwareSerial.h>
#include <ModbusMaster.h>

SoftwareSerial mbSerial(7, 6); //Tx pin, Rx pin; both on Seeed RS232 shield
ModbusMaster mbMaster;

void setup() {
  //initialize serial I/F for SerMon
  Serial.begin(9600);
  Serial.println("Start");
  Serial.println("");

  //initialize serial I/F for Modbus communication via RS232 shield
  mbSerial.begin(57600);
  
  //start Modbus master (Arduino Uno with RS232 shield); define Modbus slave address ("2", Fröling PE1 is slave) and the serial I/F to be used ("mbSerial")
  mbMaster.begin(2, mbSerial);
}

void loop() {
  uint8_t mbResult;

  //The following function codes are understood by the PE1:
  //readCoilStatus = FC01 (corresponds to "2.2 Digitale Ausgänge lesen" in Fröling Modbus documentation)
  //readInputStatus = FC02 ("2.3 Digitale Eingänge lesen")
  //readHoldingRegisters = FC03 ("2.5 Parameter lesen")
  //readInputRegisters = FC04 ("2.4 Aktuelle Werte lesen")
  //writeSingleRegister = FC06 ("2.5 Parameter schreiben")

  //request 2 byte (UINT16) of data from slave @ register address 0 (corresponds to offset 0 and thus to ID 30001 in Fröling modbus documentation) 
  mbResult = mbMaster.readInputRegisters(0, 2); //Offset 0, Kesseltemperatur
  delay(2000);
  if(mbResult == mbMaster.ku8MBSuccess) {
    //print received data on SerMon
    Serial.print("Kesseltemperatur: ");
    Serial.print(mbMaster.getResponseBuffer(0)/2); //has to be scaled with factor 2, "SKAL"
    Serial.println(" °C"); //"MEH"
  } else {
    //error in Modbus communication, print error code
    Serial.print("Error: ");
    Serial.println(mbResult);
  }
  mbMaster.clearResponseBuffer();
  
  mbResult = mbMaster.readInputRegisters(1, 2); //Offset 1, Abgastemperatur
  delay(2000);
  if(mbResult == mbMaster.ku8MBSuccess) {
    Serial.print("Abgastemperatur: ");
    Serial.print(mbMaster.getResponseBuffer(0));
    Serial.println(" °C");
  } else {
    Serial.print("Error: ");
    Serial.println(mbResult);
  }
  mbMaster.clearResponseBuffer();
  
  mbResult = mbMaster.readInputRegisters(1000, 2); //Offset 1000, Außentemperatur
  delay(2000);
  if(mbResult == mbMaster.ku8MBSuccess) {
    Serial.print("Außentemperatur: ");
    Serial.print(mbMaster.getResponseBuffer(0)/2);
    Serial.println(" °C");
  } else {
    Serial.print("Error: ");
    Serial.println(mbResult);
  }
  mbMaster.clearResponseBuffer();

  mbResult = mbMaster.readInputRegisters(2000, 2); //Offset 2000, Puffertemperatur oben
  delay(2000);
  if(mbResult == mbMaster.ku8MBSuccess) {
    Serial.print("Puffertemperatur oben: ");
    Serial.print(mbMaster.getResponseBuffer(0)/2);
    Serial.println(" °C");
  } else {
    Serial.print("Error: ");
    Serial.println(mbResult);
  }
  mbMaster.clearResponseBuffer();

  mbResult = mbMaster.readInputRegisters(2001, 2); //Offset 2001, Puffertemperatur Mitte
  delay(2000);
  if(mbResult == mbMaster.ku8MBSuccess) {
    Serial.print("Puffertemperatur Mitte: ");
    Serial.print(mbMaster.getResponseBuffer(0)/2);
    Serial.println(" °C");
  } else {
    Serial.print("Error: ");
    Serial.println(mbResult);
  }
  mbMaster.clearResponseBuffer();

  mbResult = mbMaster.readInputRegisters(2002, 2); //Offset 2002, Puffertemperatur unten
  delay(2000);
  if(mbResult == mbMaster.ku8MBSuccess) {
    Serial.print("Puffertemperatur unten: ");
    Serial.print(mbMaster.getResponseBuffer(0)/2);
    Serial.println(" °C");
  } else {
    Serial.print("Error: ");
    Serial.println(mbResult);
  }
  mbMaster.clearResponseBuffer();

  mbResult = mbMaster.readInputRegisters(1630, 2); //Offset 163, Boilertemperatur
  delay(2000);
  if(mbResult == mbMaster.ku8MBSuccess) {
    Serial.print("Boilertemperatur: ");
    Serial.print(mbMaster.getResponseBuffer(0)/2);
    Serial.println(" °C");
  } else {
    Serial.print("Error: ");
    Serial.println(mbResult);
  }
  mbMaster.clearResponseBuffer();

  mbResult = mbMaster.readInputRegisters(711, 2); //Offset 711, Rücklauftemperatur WW-Zirkulation
  delay(2000);
  if(mbResult == mbMaster.ku8MBSuccess) {
    Serial.print("Rücklauftemperatur WW-Zirkulation: ");
    Serial.print(mbMaster.getResponseBuffer(0)/2);
    Serial.println(" °C");
  } else {
    Serial.print("Error: ");
    Serial.println(mbResult);
  }
  mbMaster.clearResponseBuffer();

  mbResult = mbMaster.readInputRegisters(1030, 2); //Offset 1030, HK Vorlauftemperatur
  delay(2000);
  if(mbResult == mbMaster.ku8MBSuccess) {
    Serial.print("HK Vorlauftemperatur: ");
    Serial.print(mbMaster.getResponseBuffer(0)/2);
    Serial.println(" °C");
  } else {
    Serial.print("Error: ");
    Serial.println(mbResult);
  }
  mbMaster.clearResponseBuffer();
  
  mbResult = mbMaster.readInputRegisters(1032, 2); //Offset 1030, Raumtemperatur
  delay(2000);
  if(mbResult == mbMaster.ku8MBSuccess) {
    Serial.print("Raumtemperatur: ");
    Serial.print(mbMaster.getResponseBuffer(0)/2);
    Serial.println(" °C");
  } else {
    Serial.print("Error: ");
    Serial.println(mbResult);
  }
  mbMaster.clearResponseBuffer();



  Serial.println("------------------------------------");

}