vb.net modbus tcp 代码案例

在VB.NET中，Modbus TCP是一种常用的工业通信协议，用于设备间的通信，比如PLC、SCADA系统等。下面是一个简单的VB.NET Modbus TCP客户端的例子，它连接到服务器并发送读取线圈请求：

Imports System.Net.Sockets
Imports MODBUSPLUS

Public Class Form1
    Private Sub btnConnect_Click(sender As Object, e As EventArgs) Handles btnConnect.Click
        ' 创建TCP客户端
        Dim client As New TcpClient()
        Dim ip As String = "192.168.1.100" ' 设备IP地址
        Dim port As Integer = 502 ' Modbus默认端口
        client.Connect(ip, port)

        ' 创建ModbusMaster实例
        Dim master As New ModbusMaster(client.GetStream())
        
        ' 发送读取线圈请求
        Dim slaveId As Short = 1 ' 设备ID
        Dim functionCode As Byte = ModbusFunctions.ReadCoils
        Dim address As Short = 100 ' 要读取的寄存器地址
        Dim coils(1) As Boolean
        master.ReadCoils(slaveId, address, 1, coils)

        ' 显示结果
        For Each coil In coils
            If coil Then
                MessageBox.Show($"Register {address} is a coil (Value: True)")
            Else
                MessageBox.Show($"Register {address} is not a coil (Value: False)")
            End If
        Next
        
        ' 关闭连接
        client.Close()
    End Sub
End Class