簡單寫了個c#連接西門子PLC的小程序來練習，源代碼放在下面，可以看看


using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using S7.Net;

namespace 西門子連接上位機
{
    public partial class Form1 : Form
    {
        public Plc Myplc;
        public string IP = "192.168.1.118";//PLC的IP地址
        public void Connect()//創建連接PLC方法
        {
            try
            {
                Myplc = new Plc(CpuType.S71500, IP, 0, 1);//實例化PLC對象
            }
            catch { MessageBox.Show("連接失敗！"); }
        }
        public Form1()
        {
            InitializeComponent();
            Connect();//調用連接PLC方法
        }

        private void button1_Click(object sender, EventArgs e)
        {
            if(Myplc==null)
            {
                MessageBox.Show("連接失敗！");
                return;
            }
            try
            {
                Myplc.Open();//打開PLC連接
                button1.BackColor = Color.Lime;//改變按鈕1顏色為綠色
                button2.BackColor = Color.White;//改變按鈕2顏色為白色
                button1.Text = "已連接PLC";//改變按鈕1文字為已連接PLC
                label1.Text = "已連接到PLC";//改變label1文字為已連接到PLC
                label1.Visible = true;//顯示label1
                
            }
            catch { MessageBox.Show("連接失敗！"); }//捕獲異常
            
        }

        private void button2_Click(object sender, EventArgs e)
        {
            if (Myplc == null)
            {
                MessageBox.Show("連接失敗！");//判斷PLC是否連接成功
                return;
            }
            try
            {
                Myplc.Close();//關閉PLC連接
                button2.BackColor = Color.Lime;//改變按鈕2顏色為綠色
                button1.BackColor = Color.White;//改變按鈕1顏色為白色
                button2.Text = "已斷開PLC";//改變按鈕2文字為已斷開PLC
                label1.Visible = false;//隱藏label1
            }
            catch { MessageBox.Show("斷開失敗！"); }//捕獲異常
            
        }

        private void button3_Click(object sender, EventArgs e)
        {
            if (Myplc == null)
            {
                MessageBox.Show("連接失敗！");//判斷PLC是否連接成功
                return;
            }
            try
            {
                if ((bool)Myplc.Read("DB1.DBX0.0") == false)//判斷讀取的BOOL變量對按鈕進行取反操作
                {
                    Myplc.Write("DB1.DBX0.0", 1);//寫入BOOL變量
                    button3.BackColor = Color.Lime;//改變按鈕3顏色為綠色
                }
                else if ((bool)Myplc.Read("DB1.DBX0.0") == true)
                {
                    Myplc.Write("DB1.DBX0.0", 0);//寫入BOOL變量
                    button3.BackColor = Color.White;//改變按鈕3顏色為白色
                }
                else { MessageBox.Show("讀取或寫入失敗！"); }//捕獲異常
            }
            catch { MessageBox.Show("讀取或寫入失敗！"); }//捕獲異常
            
            
        }
    }
}