Client Connection time out

[Samuel Augustine]

I tried to read registers continously in an infinite loop, but it terminates after a while , is there a way to avoid this??

[Rossmann Engineering]

Hi,

could you attach some sourcecode?

[Samuel Augustine]

Hello,

Thank you for your response, This is what I tried:

public static void Main(string[] args)
{
for (int i = 1; i > 0; i++)
{
ModbusClient modbusClient = new ModbusClient("127.0.0.1", 502);
modbusClient.Connect();
int[] readHoldingRegisters = modbusClient.ReadHoldingRegisters(0, 10);
Console.WriteLine("Value of A " + " " + readHoldingRegisters[0].ToString());
Console.WriteLine("Value of B " + " " + readHoldingRegisters[1].ToString());
Console.WriteLine("Value of C " + " " + readHoldingRegisters[2].ToString());
Thread.Sleep(1000);
}

After few minutes it goes:
An IOException was unhandled
Unable to read data from the transport connection: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.

Please help me with this.

[Rossmann Engineering]

Hi Samuel,

what you could try is either to call the "connect()" method outside the loop, or after reading the values to disconnect.

somthing like:
public static void Main(string[] args)
{
ModbusClient modbusClient = new ModbusClient("127.0.0.1", 502);
for (int i = 1; i > 0; i++)
{
modbusClient.Connect();
int[] readHoldingRegisters = modbusClient.ReadHoldingRegisters(0, 10);
Console.WriteLine("Value of A " + " " + readHoldingRegisters[0].ToString());
Console.WriteLine("Value of B " + " " + readHoldingRegisters[1].ToString());
Console.WriteLine("Value of C " + " " + readHoldingRegisters[2].ToString());
modbusClient.Disconnect();
Thread.Sleep(1000);
}

or

public static void Main(string[] args)
{
ModbusClient modbusClient = new ModbusClient("127.0.0.1", 502);
modbusClient.Connect();
for (int i = 1; i > 0; i++)
{
int[] readHoldingRegisters = modbusClient.ReadHoldingRegisters(0, 10);
Console.WriteLine("Value of A " + " " + readHoldingRegisters[0].ToString());
Console.WriteLine("Value of B " + " " + readHoldingRegisters[1].ToString());
Console.WriteLine("Value of C " + " " + readHoldingRegisters[2].ToString());
Thread.Sleep(1000);
}

[Anonymous]

Hi,

It worked, Thank you so much.

[Tai Nguyen]

I got same error. Everything work fine but suddenly it disconnect and then i can't reconnect and get error Connection time out
my code:
private void timer3_Tick(object sender, EventArgs e)
{
timer3.Enabled = false;
int num = 34;
ModbusClient mb3 = new ModbusClient();
try
{
if (!mb3.Connected)
{
//mb3.Port = 1024;
mb3 = new ModbusClient(dtOmron.Rows[2]["IP"].ToString(), 502);
mb3.ConnectionTimeout = 1000;
mb3.Connect();
lblStatus3.Text = dtOmron.Rows[2]["IP"].ToString() + " Connected";
}

            if (!mb3.Connected)
            {
                lblStatus3.Text = dtOmron.Rows[2]["IP"].ToString() + " Disconnected";
                dtTam.Rows[0][dtOmron.Rows[2]["IP"].ToString() + "/502"] = dtOmron.Rows[2]["IP"].ToString() + " Disconnected";
            }
            else
            {
                int startingAddress = Convert.ToInt32(dtOmron.Rows[2]["StartIndex"]);
                int quantity = Convert.ToInt32(dtOmron.Rows[2]["Length"]);
                if (quantity > 0)
                {
                    int[] numArray = mb3.ReadHoldingRegisters(startingAddress, quantity + 1);

                    //ma22 1-3
                    for (int i = 50; i < 80; i++)
                    {
                        if (i.ToString()[i.ToString().Length - 1] != '7')
                        {
                            dtTam.Rows[0][num] = ChuyenDoi(i, numArray[i], numArray[i + 1]);
                            num++;
                        }
                    }
                    num = 115;
                    //ma22 10
                    for (int i = 20; i < 30; i++)
                    {
                        if (i.ToString()[i.ToString().Length - 1] != '7')
                        {
                            dtTam.Rows[0][num] = ChuyenDoi(i, numArray[i], numArray[i + 1]);
                            num++;
                        }
                    }
                    //ma22 11
                    for (int i = 10; i < 20; i++)
                    {
                        if (i.ToString()[i.ToString().Length - 1] != '7')
                        {
                            dtTam.Rows[0][num] = ChuyenDoi(i, numArray[i], numArray[i + 1]);
                            num++;
                        }
                    }
                    //ma22 12
                    for (int i = 0; i < 10; i++)
                    {
                        if (i.ToString()[i.ToString().Length - 1] != '7')
                        {
                            dtTam.Rows[0][num] = ChuyenDoi(i, numArray[i], numArray[i + 1]);
                            num++;
                        }
                    }
                    num = 196;
                    //ma22 19,20
                    for (int i = 30; i < 50; i++)
                    {
                        if (i.ToString()[i.ToString().Length - 1] != '7')
                        {
                            dtTam.Rows[0][num] = ChuyenDoi(i, numArray[i], numArray[i + 1]);
                            num++;
                        }
                    }
                    //Anneal voltage+ current cua la19 01,02
                    //la19 01
                    num = 8;
                    for (int i = 80; i < 82; i++)
                    {
                        if (i.ToString()[i.ToString().Length - 1] != '7')
                        {
                            if (i == 80)
                            {
                                float tg = numArray[i];
                                dtTam.Rows[0][num] = tg / 10;
                            }
                            else
                                dtTam.Rows[0][num] = numArray[i];


                            num++;
                        }
                    }
                    //la19 02
                    num = 21;
                    for (int i = 82; i < 84; i++)
                    {
                        if (i.ToString()[i.ToString().Length - 1] != '7')
                        {
                            if (i == 82)
                            {
                                float tg = numArray[i];
                                dtTam.Rows[0][num] = tg / 10;
                            }
                            else
                                dtTam.Rows[0][num] = numArray[i];


                            num++;
                        }
                    }
                }
                mb3.Disconnect();

            }

            //  lblStatus3.Text = dtOmron.Rows[2]["IP"].ToString() +" Disconnected";
        }
        catch (Exception exception)
        {
            lblStatus3.Text = dtOmron.Rows[2]["IP"].ToString() + " Error: " + exception.Message;
            dtTam.Rows[0][dtOmron.Rows[2]["IP"].ToString() + "/502"] = "Error: " + exception.Message;
            mb3.Disconnect();
        }
        timer3.Enabled = true;

}