How to communicate with a PLC using C#?

2 years ago
Noah Thompson
2 minutes

To communicate with a PLC, you can use the programming language C# to achieve this. Below are some commonly used methods:

  1. Serial communication: PLCs typically communicate with computers through serial ports. You can use the SerialPort class in C# to communicate with a PLC. First, you need to open the serial port and set appropriate parameters such as baud rate, data bits, stop bits, and parity. Then, you can use the Read and Write methods of the SerialPort class to read and write data.

Sample code:

using System.IO.Ports;

SerialPort port = new SerialPort("COM1", 9600, Parity.None, 8, StopBits.One);
port.Open();
port.Write("你的命令"); // 向PLC发送命令
string response = port.ReadLine(); // 从PLC读取响应
port.Close();
  1. Using Ethernet communication: Some PLCs support Ethernet communication. You can use the Socket class in C# or third-party libraries like Modbus.NET to communicate with the PLC. First, you need to create a Socket connection to the PLC’s IP address and port number. Then, you can use the Send and Receive methods of the Socket class to send and receive data.

Sample code:

using System.Net;
using System.Net.Sockets;

IPAddress ipAddress = IPAddress.Parse("PLC的IP地址");
int port = 502;
TcpClient client = new TcpClient();
client.Connect(ipAddress, port);
NetworkStream stream = client.GetStream();

byte[] command = { 0x01, 0x02, 0x03 }; // 发送的命令
stream.Write(command, 0, command.Length);

byte[] response = new byte[256]; // 接收的响应
int bytesRead = stream.Read(response, 0, response.Length);

stream.Close();
client.Close();

These codes are just simple examples; the specific communication protocol and command format need to be determined based on the PLC model and communication protocol you are using. If you are using a specific brand and model of PLC, you can refer to its related documentation for more detailed communication protocol and command format information.

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