====== Creating a CUWIN Modbus RTU Master with NModbus ======

In this document we'll use the CUWIN as a Modbus master, and a CUBLOC-based [[https://comfiletech.com/new-products-for-2014-2015/msb612ra-dc/|MSB612RA-DC]] as a Modbus slave.

{{ :cuwin:creating_a_cuwin_modbus_rtu_master_with_nmodbus:cubloccuwin.png |}}

===== Create the Modbus Slave =====

{{ :cuwin:creating_a_cuwin_modbus_rtu_master_with_nmodbus:msb612ra-dc.png |}}

Configure the serial settings in MSB Logic.

{{ :cuwin:creating_a_cuwin_modbus_rtu_master_with_nmodbus:msbsetup.png?800 |}}

Nothing else is needed in Ladder Logic except and ''END''ing rung.

{{ :cuwin:creating_a_cuwin_modbus_rtu_master_with_nmodbus:msbladderlogic.png?800 |}}

===== Connecting the CUWIN to the MSB612RA-DC =====
For this exercise we will use the [[https://comfiletech.com/touch-panel-pc/windows-ce-panel-pc/cwv-070br-7-bezel-cortex-a8-1ghz/|CUWIN CWV070]] as the Modbus master.

{{ :cuwin:creating_a_cuwin_modbus_rtu_master_with_nmodbus:cwv070br.png |}}

Connect the CUWIN's RS-232 COM1 port to the MSB612RA-DC RS-232 Ch1 port.

{{ :cuwin:creating_a_cuwin_modbus_rtu_master_with_nmodbus:rs-232connection.png |}}

{{ :cuwin:creating_a_cuwin_modbus_rtu_master_with_nmodbus:cuwin_cwv_msb_connection.jpg |}}

===== Create the Modbus Master =====

==== NModbus ====
NModbus is a free and open source implementation of the Modbus protocol for the .Net Framework and .Net Compact Framework. It is currently hosted at https://code.google.com/p/nmodbus/ but there are also [[https://github.com/search?utf8=%E2%9C%93&q=nModbus|other forks on GitHub]].

{{ :cuwin:creating_a_cuwin_modbus_rtu_master_with_nmodbus:nmodbussite.png |}}

Download the NModbus binaries.

{{ :cuwin:creating_a_cuwin_modbus_rtu_master_with_nmodbus:nmodbussite2.png |}}

After downloading and extracting the NModbus binaries from the repository, there will be two folders inside the "bin" folder: //net// and //netcf//. //net// is for the .Net Framework, and //netcf// is for the .Net Compact Framework.  The CUWIN is a .Net Compact Framework device, so //netcf// is the appropriate folder.


{{ :cuwin:creating_a_cuwin_modbus_rtu_master_with_nmodbus:netcffolder.png |}}

==== Programming the CUWIN ====

Add a reference to the //Modbus.dll// file in //netcf// folder introduced above. 

{{ :cuwin:creating_a_cuwin_modbus_rtu_master_with_nmodbus:nmodbusaddreference.png |}}


Add a ''using'' declaration to the source file that will contain the Modbus Master code.

<code csharp>
using Modbus.Device;
</code>

Create a new [[https://msdn.microsoft.com/en-us/library/system.io.ports.serialport%28v=vs.90%29.aspx|SerialPort]] on COM1 with the same serial settings as the Modbus slave.

<code csharp>
_serialPort = new SerialPort("COM1", 115200);
_serialPort.Open();
</code>
    
Initialize a new ''ModbusSerialMaster'' with the ''_serialPort'' as its transport.

<code csharp>
_modbusMaster = ModbusSerialMaster.CreateRtu(_serialPort);
_modbusMaster.Transport.ReadTimeout = 500;
_modbusMaster.Transport.WriteTimeout = 500;
_modbusMaster.Transport.Retries = 0;
</code>

Then call any of the given methods to query a Modbus slave:

<code csharp>
bool[] ReadCoils(byte slaveAddress, ushort startAddress, ushort numberOfPoints);

ushort[] ReadHoldingRegisters(byte slaveAddress, ushort startAddress, ushort numberOfPoints);

ushort[] ReadInputRegisters(byte slaveAddress, ushort startAddress, ushort numberOfPoints);

bool[] ReadInputs(byte slaveAddress, ushort startAddress, ushort numberOfPoints);

ushort[] ReadWriteMultipleRegisters(byte slaveAddress, ushort startReadAddress, 
         ushort numberOfPointsToRead, ushort startWriteAddress, ushort[] writeData);

void WriteMultipleCoils(byte slaveAddress, ushort startAddress, bool[] data);

void WriteMultipleRegisters(byte slaveAddress, ushort startAddress, ushort[] data);

void WriteSingleCoil(byte slaveAddress, ushort coilAddress, bool value);

void WriteSingleRegister(byte slaveAddress, ushort registerAddress, ushort value);
</code>

===== Sample Project =====
The following sample project will toggle MSB624RA-DC's relay 32 (at address 32) and read from the MSB624RA-DC's analog input (at address 276). Refer to the following table for the MSB624RA-DCs Modbus memory map.

^  Word (Holding/Input Registers) \\    Function Codes: 3, 4, 6, 16  ^^
^ Address (base 10)               ^ Data Region (base 10)  ^
| 0 ~ 255                         | D Region (D0 ~ D255)   |
| 256 ~ 355                       | Y Region (Y0 ~ Y99) \\ ADC Result Y20 ~ Y27 (276 ~ 283)   |
| 1000 ~ 1255 | T Region (T0 ~ T255)    |
| 2000 ~ 2255 | C Region (C0 ~ C255)    |
| 3000 ~ 3255 | WM Region (WM0 ~ WM255)    |

^  Bit (Coil, Input Status) \\    Function Codes: 1, 2, 4, 15  ^^
^ Address (base 10)               ^ Data Region (base 10)  ^
| 0 ~ 127                | P Region (P0 ~ P127)  |
| 4096 ~ 6143            | M Region (M0 ~ M2047)  |

==== C# Source Code ====

{{:cuwin:creating_a_cuwin_modbus_rtu_master_with_nmodbus:cuwin_cwv_modbus.zip|Download the C# Project Files}}

<code csharp>
using System;
using System.Linq;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Threading;
using Modbus.Device;
using System.IO.Ports;
 
namespace NModbusTest
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
 
        ModbusSerialMaster _modbusMaster;
        SerialPort _serialPort;
        const int SLAVE_ADDRESS = 1;
 
        private void Form1_Load(object sender, EventArgs e)
        {
            _serialPort = new SerialPort("COM1", 115200);
            _serialPort.Open();
 
            _modbusMaster = ModbusSerialMaster.CreateRtu(_serialPort);
            _modbusMaster.Transport.ReadTimeout = 500;
            _modbusMaster.Transport.WriteTimeout = 500;
            _modbusMaster.Transport.Retries = 0;
 
        }
 
        void ReportError(string s)
        {
            MessageBox.Show(s);
        }
 
        private void ReadADC()
        {
            try
            {
                ushort[] result = _modbusMaster.ReadInputRegisters(SLAVE_ADDRESS, 276, 1);
                _adcLabel.Text = result[0].ToString();
            }
            catch (Exception ex)
            {
                ReportError(ex.Message);
            }
        }
 
        private void ReadDigitalOutput()
        {
            try
            {
                bool[] result = _modbusMaster.ReadCoils(SLAVE_ADDRESS, 32, 1);
                if (result[0])
                {
                    _digitalOutLabel.Text = "ON";
                }
                else
                {
                    _digitalOutLabel.Text = "OFF";
                }
            }
            catch (Exception ex)
            {
                ReportError(ex.Message);
            }
        }
 
        private void WriteDigitalOutput(bool on)
        {
            try
            {
                _modbusMaster.WriteSingleCoil(SLAVE_ADDRESS, 32, on);
            }
            catch (Exception ex)
            {
                ReportError(ex.Message);
            }
        }
 
        private void _digitalOutReadButton_Click(object sender, EventArgs e)
        {
            ReadDigitalOutput();
        }
 
        private void _onButton_Click(object sender, EventArgs e)
        {
            WriteDigitalOutput(true);
        }
 
        private void _offButton_Click(object sender, EventArgs e)
        {
            WriteDigitalOutput(false);
        }
 
        private void _adcReadButton_Click(object sender, EventArgs e)
        {
            ReadADC();
        }
 
        private void Form1_Closing(object sender, CancelEventArgs e)
        {
            _modbusMaster.Dispose();
            _modbusMaster = null;
 
            _serialPort.Close();
            _serialPort.Dispose();
            _serialPort = null;
        }
    }
}

</code>

==== VB.NET Source Code ====

{{:cuwin:creating_a_cuwin_modbus_rtu_master_with_nmodbus:nmodbustestvb.zip|Download the VB.Net Project Files}}

<code vb.net>
Imports System
Imports System.Linq
Imports System.Collections.Generic
Imports System.ComponentModel
Imports System.Data
Imports System.Drawing
Imports System.Text
Imports System.Windows.Forms
Imports System.Threading
Imports Modbus.Device
Imports System.IO.Ports

Public Class Form1

    Private _modbusMaster As ModbusSerialMaster
    Private _serialPort As SerialPort
    Const SLAVE_ADDRESS As Integer = 1


    Private Sub ReportError(ByVal s As String)
        MessageBox.Show(s)
    End Sub

    Private Sub ReadADC()
        Try
            Dim result As UShort() = _modbusMaster.ReadInputRegisters(SLAVE_ADDRESS, 276, 1)
            _adcLabel.Text = result(0).ToString()
        Catch ex As Exception
            ReportError(ex.Message)
        End Try
    End Sub

    Private Sub ReadDigitalOutput()
        Try
            Dim result As Boolean() = _modbusMaster.ReadCoils(SLAVE_ADDRESS, 32, 1)

            If result(0) Then
                _digitalOutLabel.Text = "ON"
            Else
                _digitalOutLabel.Text = "OFF"
            End If

        Catch ex As Exception
            ReportError(ex.Message)
        End Try
    End Sub

    Private Sub WriteDigitalOutput(ByVal [on] As Boolean)
        Try
            _modbusMaster.WriteSingleCoil(SLAVE_ADDRESS, 32, [on])
        Catch ex As Exception
            ReportError(ex.Message)
        End Try
    End Sub

    Private Sub _digitalOutReadButton_Click(ByVal sender As Object, ByVal e As EventArgs)
        ReadDigitalOutput()
    End Sub

    Private Sub _onButton_Click(ByVal sender As Object, ByVal e As EventArgs)
        WriteDigitalOutput(True)
    End Sub

    Private Sub _offButton_Click(ByVal sender As Object, ByVal e As EventArgs)
        WriteDigitalOutput(False)
    End Sub

    Private Sub _adcReadButton_Click(ByVal sender As Object, ByVal e As EventArgs)
        ReadADC()
    End Sub

    Private Sub Form1_Closing(ByVal sender As Object, ByVal e As CancelEventArgs)
        _modbusMaster.Dispose()
        _modbusMaster = Nothing
        _serialPort.Close()
        _serialPort.Dispose()
        _serialPort = Nothing
    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        _serialPort = New SerialPort("COM1", 115200)
        _serialPort.Open()
        _modbusMaster = ModbusSerialMaster.CreateRtu(_serialPort)
        _modbusMaster.Transport.ReadTimeout = 500
        _modbusMaster.Transport.WriteTimeout = 500
        _modbusMaster.Transport.Retries = 0
    End Sub
End Class

</code>

==== Demonstration Video ====

{{ :cuwin:creating_a_cuwin_modbus_rtu_master_with_nmodbus:nmodbusexample.mp4?700x394 |}}