using Modbus.Device;            // NModbus namespace
using System.IO.Ports;
using static System.Console;

internal class Program
{
    // Registers
    private const ushort    READINPUT1 = 100;
    private const ushort    INPUT1ERROR = 101;
    private const ushort    ALARM1STATUS = 102;
    private const ushort    ALARM2STATUS = 106;
    private const ushort    ANALOGINPUT1DECIMAL = 606;
    private const ushort    POWEROUTPUT1A = 103;
    private const ushort    SETPOINT1 = 300;
    private const ushort    CURRENTDAY = 1920;
    private const ushort    CURRENTMONTH = 1919;
    private const ushort    CURRENTYEAR = 1921;
    private const ushort    CURRENTHOUR = 1916;
    private const ushort    CURRENTMINUTE = 1917;
    private const ushort    CURRENTSECOND = 1918;
    private const ushort    OUTPUT1AFUNCTION = 700;
    private const ushort    OUTPUT1ACYCLETIMETYPE = 509;
    private const ushort    OUTPUT1ACYCLETIME = 506;
    private const ushort    DIGITALINPUT1FUNCTION = 1060;
    private const ushort    DIGITALINPUT1CONDITION = 1061;
    private const ushort    DIGITALINPUT1STATUS = 201;
    private const ushort    POWEROUTACTION = 1206;
    private const ushort    POWEROUTTIME = 1213;
    private const ushort    ANALOGINPUTUNITS = 608;
    private const ushort    CONTROLOUTPUTTYPE = 701;
    private const ushort    ANALOGINPUT1SENSORTYPE = 601;
    private const ushort    ANALOGINPUT1SENSOR = 600;
    private const ushort    ANALOGINPUT1SETPOINTHIGHLIMIT = 603;
    private const ushort    ANALOGINPUT1SETPOINTLOWLIMIT = 602;
    private const ushort    TEMPSCALEDISPLAY = 1923;
    private const ushort    TEMPSCALE = 901;
    private const ushort    ANALOGOUTPUT1ATYPE = 701;
    private const ushort    PROPORTIONALBAND = 500;

    // Configuration
    private const byte      slaveID = 1;

    private static void Main(string[] args)
    {
        ushort[] registers;

        // Initialize the F4
        SerialPort serialPort = (SerialPort)InitializeModbusSerialPort();
        ModbusSerialMaster master = (ModbusSerialMaster)InitializeModbusMaster(serialPort);

        // Then, run it
        try
        {
            // Monitor continuously
            while (true)
            {
                // Check for escape key press
                if (KeyAvailable)
                {
                    ConsoleKeyInfo key = ReadKey(true);
                    if (key.Key == ConsoleKey.Escape)
                    {
                        WriteLine("<ESC> pressed. Exiting...");
                        break;
                    }
                }

                // Display current process values
                try
                {
                    registers = master.ReadInputRegisters(slaveID, INPUT1ERROR, 1);
                    if (registers[0] != 0)
                    {
                        WriteLine("Failure in the temperature input channel; program ends here...\n");
                        return;
                    };
                    registers = master.ReadInputRegisters(slaveID, READINPUT1, 1);
                    Write("temperature is {0:F1}; ", registers[0] / 10.0);
                    registers = master.ReadInputRegisters(slaveID, POWEROUTPUT1A, 1);
                    Write("power output is {0:F2}%\n", registers[0] / 100.0);
                    // Pause before next read
                    Thread.Sleep(750);
                }
                catch (Exception ex)
                {
                    WriteLine($"Error: {ex.Message}");
                    break;
                }
            }
        }
        catch (Exception ex)
        {
            WriteLine($"Initialization error: {ex.Message}");
        }
        finally
        {
            // Shut off the output
            master?.WriteSingleRegister(slaveID, SETPOINT1, 0);

            // Clean up
            master?.Dispose();
            serialPort?.Close();
        }

        static object InitializeModbusSerialPort()
        {
            SerialPort serialPort;

            serialPort = new SerialPort
            {
                PortName = "COM1",
                BaudRate = 19200,
                DataBits = 8,
                Parity = Parity.None,
                StopBits = StopBits.One,
                ReadTimeout = 1000
            };
            serialPort.Open();
            return serialPort;
        }

        static object InitializeModbusMaster(SerialPort serialPort)
        {
            ushort[] registers;
            ushort setPoint = 1000;
            ModbusSerialMaster master;
            DateTime dateTime;

            master = ModbusSerialMaster.CreateRtu(serialPort);

            // Set sensor type
            WriteLine("Set sensor type to 100 Ω DIN platinum RTD");
            master.WriteSingleRegister(slaveID, ANALOGINPUT1SENSOR, 1);
            master.WriteSingleRegister(slaveID, ANALOGINPUT1SENSORTYPE, 11);

            // Set to one decimal place (this cannot be the first initialization instruction)
            WriteLine("Set to one decimal place on display");
            master.WriteSingleRegister(slaveID, ANALOGINPUT1DECIMAL, 1);

            // Display current setpoint high and low limits
            registers = master.ReadInputRegisters(slaveID, ANALOGINPUT1SETPOINTLOWLIMIT, 1);
            WriteLine("Setpoint low limit is {0}", registers[0]);
            registers = master.ReadInputRegisters(slaveID, ANALOGINPUT1SETPOINTHIGHLIMIT, 1);
            WriteLine("Setpoint high limit is {0}", registers[0]);

            // Set to proportional mode
            WriteLine("Make proportional band 5°F");
            master.WriteSingleRegister(slaveID, PROPORTIONALBAND, 5);

            // Set output function to heating
            WriteLine("Output function is heating");
            master.WriteSingleRegister(slaveID, OUTPUT1AFUNCTION, 1);

            // Set analog output1 to 4-20 ma
            WriteLine("Set the analog output to 4-20 MA");
            master.WriteSingleRegister(slaveID, ANALOGOUTPUT1ATYPE, 0);

            // Set analog input parameter to temperature
            master.WriteSingleRegister(slaveID, ANALOGINPUTUNITS, 0);

            // Set temperature SCALE to ON
            master.WriteSingleRegister(slaveID, TEMPSCALEDISPLAY, 1);

            // Set temperature scale type to Fahrenheit
            master.WriteSingleRegister(slaveID, TEMPSCALE, 0);

            // Set power failure response
            master.WriteSingleRegister(slaveID, POWEROUTACTION, 2);

            // Set output1 cycle time type to variable burst
            master.WriteSingleRegister(slaveID, OUTPUT1ACYCLETIMETYPE, 0);

            // Read current output1 cycle time
            registers = master.ReadInputRegisters(slaveID, OUTPUT1ACYCLETIME, 1);
            WriteLine("Output cycle time is {0}", registers[0]);

            // Set output1 cycle time to new value
            master.WriteSingleRegister(slaveID, OUTPUT1ACYCLETIME, 500);

            // Check new value
            registers = master.ReadInputRegisters(slaveID, OUTPUT1ACYCLETIME, 1);
            WriteLine("Output cycle time is now {0}", registers[0]);

            // Write setpoint to F4
            WriteLine("Setting the process variable setpoint");
            master.WriteSingleRegister(slaveID, SETPOINT1, setPoint);

            // Verify setpoint value
            WriteLine("Verifying the setpoint value");
            registers = master.ReadInputRegisters(slaveID, SETPOINT1, 1);
            WriteLine("Setpoint is {0:F1}", registers[0] / 10.0);

            // Set F4 clock to current date and time
            dateTime = DateTime.Now;
            master.WriteSingleRegister(slaveID, CURRENTDAY, (ushort)dateTime.Day);
            master.WriteSingleRegister(slaveID, CURRENTMONTH, (ushort)dateTime.Month);
            master.WriteSingleRegister(slaveID, CURRENTYEAR, (ushort)dateTime.Year);
            master.WriteSingleRegister(slaveID, CURRENTHOUR, (ushort)dateTime.Hour);
            master.WriteSingleRegister(slaveID, CURRENTMINUTE, (ushort)dateTime.Minute);
            master.WriteSingleRegister(slaveID, CURRENTSECOND, (ushort)dateTime.Second);
            WriteLine("Set F4 clock to {0} {1}", dateTime.ToLongTimeString(), dateTime.ToLongDateString());

            return master;
        }
    }
}