Modbus TCP 规范详解 🌐

端口: 502
超时: 5秒
最大连接: 10
连接类型: 长连接

端口: 自定义(非502)
超时: 10秒
最大连接: 50
连接类型: 连接池

from pymodbus.client import ModbusTcpClient
from pymodbus.exceptions import ModbusException

def read_registers(host, port=502, unit=1):
    client = ModbusTcpClient(
        host=host,
        port=port,
        timeout=5
    )

    try:
        if client.connect():
            # 读取保持寄存器
            result = client.read_holding_registers(
                address=0,
                count=10,
                slave=unit
            )

            if not result.isError():
                return result.registers
            else:
                print(f"读取错误: {result}")
    except ModbusException as e:
        print(f"Modbus异常: {e}")
    finally:
        client.close()

    return None

from pymodbus.server import StartTcpServer
from pymodbus.datastore import ModbusSequentialDataBlock
from pymodbus.datastore import ModbusSlaveContext, ModbusServerContext

def run_server():
    # 创建数据存储
    store = ModbusSlaveContext(
        di=ModbusSequentialDataBlock(0, [0]*100),     # 离散输入
        co=ModbusSequentialDataBlock(0, [0]*100),     # 线圈
        hr=ModbusSequentialDataBlock(0, [0]*100),     # 保持寄存器
        ir=ModbusSequentialDataBlock(0, [0]*100)      # 输入寄存器
    )

    context = ModbusServerContext(slaves=store, single=True)

    # 启动TCP服务器
    StartTcpServer(
        context=context,
        address=("0.0.0.0", 502)
    )

using Modbus.Device;
using System.Net.Sockets;

public class ModbusTcpClientExample
{
    public ushort[] ReadRegisters(string ip, int port, byte unitId)
    {
        using (TcpClient client = new TcpClient(ip, port))
        {
            var modbusClient = ModbusIpMaster.CreateIp(client);

            // 读取保持寄存器
            ushort[] registers = modbusClient.ReadHoldingRegisters(
                unitId, 0, 10);

            return registers;
        }
    }
}