Form1.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.IO;
using System.IO.Ports;
using System.Diagnostics;
using ZedGraph;


namespace Seri_Port_Terminal
{
    public partial class Form1 : Form
    {
        string Gelen = string.Empty;
        string[] ports = SerialPort.GetPortNames();
        // 1
        GraphPane myPane = new GraphPane();
        RollingPointPairList listPointsOne = new RollingPointPairList(40);
        LineItem myCurveOne;
        RollingPointPairList listPointsTwo = new RollingPointPairList(40);
        LineItem myCurveTwo;
        RollingPointPairList listPointsThree = new RollingPointPairList(40);
        LineItem myCurveThree;

        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
           //1
            myPane = zedGraphControl1.GraphPane;
            myPane.XAxis.Title.Text = "Time";
            myPane.YAxis.Title.Text = "Data";
            zedGraphControl1.Invalidate();
            zedGraphControl1.AxisChange();
            zedGraphControl1.Refresh(); 

            /* Adding connected ports */
            foreach (string port in ports)
            {
                cbComPort.Items.Add(port);
            }
            /* Baudrates are added */
            cbBaud.Items.Add("2400");
            cbBaud.Items.Add("4800");
            cbBaud.Items.Add("9600");
            cbBaud.Items.Add("19200");
            cbBaud.Items.Add("38400");
            cbBaud.Items.Add("57600");
            cbBaud.Items.Add("115200");
            cbBaud.SelectedIndex = 3;

        }



        private void btnBaglan_Click(object sender, EventArgs e)
        {
            if (SeriPort.IsOpen == false)
            {
                if (cbComPort.Text == "")
                    return;
                SeriPort.PortName = cbComPort.Text;
                SeriPort.BaudRate = Convert.ToInt32(cbBaud.Text);
                try
                {
                    SeriPort.Open();
                }
                catch (Exception er)
                {
                    MessageBox.Show("Error:" + er.Message);
                }
            }
            else
            {
                rtbEkran.Text = "seriport already open";
            }
        }

        private void Form1_FormClosed(object sender, FormClosedEventArgs e)
        {
            if (SeriPort.IsOpen == true)
            {
                SeriPort.Close();
            }
        }

        private void btnKes_Click(object sender, EventArgs e)
        {
            if (SeriPort.IsOpen == true)
            {
                SeriPort.Close();
            }
        }

        private void SeriPort_DataReceived(object sender, SerialDataReceivedEventArgs e)
        {
            try
            {
                Gelen = SeriPort.ReadLine();
                this.Invoke(new EventHandler(DisplayText));
            }
            catch (Exception er)
            {
                MessageBox.Show("Error:" + er.Message);
            }
        }

        private void DisplayText(object s, EventArgs e)
        {
            label31.Text = Gelen;
            if (timer1.Enabled == true)
            {
                string ctrl = Gelen.Substring(0, 1);
                if (ctrl=="$")
                {
                string[] parsed = Gelen.Split(',');
                string ArananC = ",";
                int bulunanC = (Gelen.Length - Gelen.Replace(ArananC, "").Length) / ArananC.Length;
                if (bulunanC == 4)
                {
                    label17.Text = parsed[1];
                    label25.Text = parsed[2];
                    label24.Text = parsed[3];
                }
            }
        }
            rtbEkran.Text += Gelen;
            rtbEkran.SelectionStart = rtbEkran.Text.Length;
            rtbEkran.ScrollToCaret();
            
            Gelen = String.Empty;
        }

        private void btnEkraniTemizle_Click(object sender, EventArgs e)
        {
            rtbEkran.Clear();
        }

        private void btnGonder_Click(object sender, EventArgs e)
        {
            if (SeriPort.IsOpen == true)
            {
                if (chbCR.Checked == true && chbLF.Checked == false)
                {
                    SeriPort.Write(rtbGonder.Text + "\r");
                }
                else if (chbCR.Checked == false && chbLF.Checked == true)
                {
                    SeriPort.Write(rtbGonder.Text + "\n");
                }
                else if (chbCR.Checked == true && chbLF.Checked == true)
                {
                    SeriPort.Write(rtbGonder.Text + "\r\n");
                }
                else
                {
                    SeriPort.Write(rtbGonder.Text);
                }
            }
            else
            {
                MessageBox.Show("No Connection");
            }
        }

        private void btnKaydet_Click(object sender, EventArgs e)
        {
            saveFileDialog1.Title = "Please select place to save file";
            saveFileDialog1.Filter = "(*.doc)|*.doc|(*.txt)|*.txt|Tüm dosyalar(*.*)|*.*";
            saveFileDialog1.FilterIndex = 2;
            saveFileDialog1.InitialDirectory = "C:\\";
            saveFileDialog1.ShowDialog();

            StreamWriter Kaydet = new StreamWriter(saveFileDialog1.FileName);
            Kaydet.Write(rtbEkran.Text);
            Kaydet.Close();
        }

        private void btnAc_Click(object sender, EventArgs e)
        {
            //Open button
            if (openFileDialog1.ShowDialog() == DialogResult.OK)
            try //
            {
                rtbGonder.LoadFile(openFileDialog1.FileName,RichTextBoxStreamType.PlainText);
            }
            catch 
            {
                MessageBox.Show(openFileDialog1.FileName + " Can not open this file");
            }
        }

        private void btnSil_Click(object sender, EventArgs e)
        {
            rtbGonder.Clear();
        }

        private void tabPage1_Click(object sender, EventArgs e)
        {

        }

        public void button1_Click(object sender, EventArgs e)
        {
            timer1.Enabled = true;
        }

        private void zedGraphControl1_Load(object sender, EventArgs e)
        {

        }

        private void button2_Click(object sender, EventArgs e)
        {
            timer1.Enabled = false;
        }

        private void timer1_Tick(object sender, EventArgs e)
        {
            int sayi = Convert.ToInt32(label10.Text);
            sayi++;
            label10.Text = sayi.ToString();
            //
            myPane = zedGraphControl1.GraphPane;
            //1
            double x = Convert.ToDouble(label10.Text);
            double y1 = double.Parse(label17.Text, System.Globalization.CultureInfo.InvariantCulture); 
            listPointsOne.Add(x, y1);
            myCurveOne = myPane.AddCurve(null, listPointsOne, Color.Blue, SymbolType.Circle);
            //2            
            double y2 = double.Parse(label25.Text, System.Globalization.CultureInfo.InvariantCulture);
            listPointsOne.Add(x, y2);
            myCurveTwo = myPane.AddCurve(null, listPointsTwo, Color.Red, SymbolType.Circle);
            //3
            double y3 = double.Parse(label24.Text, System.Globalization.CultureInfo.InvariantCulture);
            listPointsOne.Add(x, y3);
            myCurveThree = myPane.AddCurve(null, listPointsThree, Color.Green, SymbolType.Circle);
            //Grafiği yenileme
            zedGraphControl1.Invalidate();
            zedGraphControl1.AxisChange();
            zedGraphControl1.Refresh();
        }

    }
}