NModbus的主站开发
1.开发环境要求：PC端作为主站，控制器作为从站
2.PC端初始化代码：
serialPort = new SerialPort(); serialPort.PortName = "COM1"; serialPort.BaudRate = 9600; serialPort.DataBits = 8; serialPort.StopBits = StopBits.One; serialPort.Parity = Parity.Even; master = ModbusSerialMaster.CreateRtu(serialPort); master.Transport.ReadTimeout = 2000; master.Transport.Retries = 10; master.Transport.WriteTimeout = 2000; serialPort.Open();3.PC端读写代码：（slaveNum:从站Slave ID，addrNum:读取寄存器起始地址，len:读取寄存器长度）功能码03
ushort[] recv = master.ReadHoldingRegisters((byte)slaveNum, (ushort)addrNum, (byte)len);4.控制器收到指令格式：
如0A 03 9C 47 00 01 1B 34
0A-SlaveID
03-功能码
9C-寄存器地址高位
47 -寄存器地址低位
00 -读取长度高位
01-读取长度低位
1B 34-校验位
5.Modbus Slave工具测试
设置Connection-Connection Setup，根据上面设置RTU连接方式，Modbus Slave设置如下：（Master设置的串口参数必须如下的配置相同） 设置SetUp-Slave Definition，Master设置的SlaveID必须跟下图配置的保持一致，Function：功能码，Address：显示的寄存器起始地址，Quanity：寄存器的数量 配置完成后点击连接，连接成功后的状态如下： 查看通讯数据帧，界面的Display-Communication…功能Modbus的从站开发
1.开发环境要求：PC作为从站，控制器作为主站，从站启动监听，触发事件，更新数据库至DataStore
2.PC端初始化代码：
comPort.PortName = "COM1"; comPort.BaudRate = 9600; comPort.DataBits = 8; comPort.Parity = Parity.Even; comPort.StopBits = StopBits.One; comPort.Open(); slave = ModbusSerialSlave.CreateRtu(slaveID, comPort); slave.ModbusSlaveRequestReceived += new EventHandler<ModbusSlaveRequestEventArgs>(Modbus_Request_Event); slave.DataStore = Modbus.Data.DataStoreFactory.CreateDefaultDataStore(); slave.DataStore.DataStoreWrittenTo += new EventHandler<DataStoreEventArgs>(Modbus_DataStoreWriteTo); slave.Listen();主站触发请求事件代码：
private void Modbus_Request_Event(object sender, Modbus.Device.ModbusSlaveRequestEventArgs e) { try { //request from master byte fc = e.Message.FunctionCode; byte[] data = e.Message.MessageFrame; byte[] byteStartAddress = new byte[] { data[3], data[2] }; byte[] byteNum = new byte[] { data[5], data[4] }; Int16 StartAddress = BitConverter.ToInt16(byteStartAddress, 0); Int16 NumOfPoint = BitConverter.ToInt16(byteNum, 0); BOOL = true; FCNUM = fc.ToString(); /* if (fc.ToString() == "6") { //AO slave.DataStore.HoldingRegisters[StartAddress] = 16; slave.DataStore.HoldingRegisters[StartAddress + 1] = 17; } */ Console.WriteLine(fc.ToString() + "," + StartAddress.ToString() + "," + NumOfPoint.ToString()); } catch (Exception exc) { FormMainUn.runStatusFile.WriteString("", "readReg", "3"); FormMainUn.runStatusFile.WriteString("","readRegErrorMsg",exc.Message); MessageBox.Show(exc.ToString()); } }写DataStore事件代码：
private void Modbus_DataStoreWriteTo(object sender, Modbus.Data.DataStoreEventArgs e) { //this.Text = "DataType=" + e.ModbusDataType.ToString() + " StartAdress=" + e.StartAddress; int iAddress = e.StartAddress;//e.StartAddress; switch (e.ModbusDataType) { case ModbusDataType.HoldingRegister: for (int i = 0; i < e.Data.B.Count; i++) { //Set AO slave.DataStore.HoldingRegisters[e.StartAddress + i + 1] = e.Data.B[i]; //e.Data.B[i] already write to slave.DataStore.HoldingRegisters[e.StartAddress + i + 1] //e.StartAddress starts from 0 //You can set AO value to hardware here //DoAOUpdate(iAddress, e.Data.B[i].ToString()); iAddress++; } break; case ModbusDataType.Coil: for (int i = 0; i < e.Data.A.Count; i++) { //Set DO slave.DataStore.CoilDiscretes[e.StartAddress + i + 1] = e.Data.A[i]; //e.Data.A[i] already write to slave.DataStore.CoilDiscretes[e.StartAddress + i + 1] //e.StartAddress starts from 0 //You can set DO value to hardware here //DoDOUpdate(iAddress, e.Data.A[i]); iAddress++; if (e.Data.A.Count == 1) { break; } } break; } }3.PC读数据代码：
public void PCReadDatafromPC(ushort RAddress, out int data) { int AOAddress; RAddresstoAOAddress(RAddress, out AOAddress); ushort data1 = slave.DataStore.HoldingRegisters[AOAddress]; ushort data2 = slave.DataStore.HoldingRegisters[AOAddress + 1]; ConcatNum(data1, data2, out data); }4.寄存器的数据都存储在PC端的DataStore中
5.Modbus Poll工具测试
设置Connection-Connection Setup，根据上面设置RTU连接方式，Modbus Poll设置如下：（Slave设置的串口参数必须如下的配置相同） 设置Setup-Read/Write definition,SlaveID需要跟Slave从站设置相同,Scan Rate:间隔时间 修改寄存器内的值，双击该寄存器的地址 点击Send按钮后，会自动触发Slave的Modbus_DataStoreWriteTo方法，修改DataStore内的值需安装vspd虚拟串口工具。通过工具添加COM1和COM2两个端口，进行以上测试
测试工具：https://download.csdn.net/download/lx_Angel/12981954
