前言在工业自动化和数据采集领域，MODBUS TCP 协议因其简单易用和广泛支持而被广泛应用。C# 作为一种编程语言，结合 NModbus 库，可以高效地实现与 MODBUS 设备的通信。
本文将详细介绍如何使用 C# 和 NModbus 库来实现 MODBUS TCP 协议下的字符串和浮点数的读写操作。
通过本文，能够掌握如何在实际项目中集成这些功能，提高数据处理的效率和准确性。
引用NModbus
在NuGet搜索NModbus，添加引用。
封装ModbusTcp类public class ModbusTCP{
private ModbusFactory modbusFactory;
private IModbusMaster master;
private TcpClient tcpClient;
public string IPAdress {
get;
set; }
public int Port {
get;
set; }
public bool Connected
{
get => tcpClient.Connected;
}
public ModbusTCP(string ip, int port) {
IPAdress = ip;
Port = port;
modbusFactory =
new ModbusFactory();
tcpClient =
new TcpClient(IPAdress, Port);
master = modbusFactory.CreateMaster(tcpClient);
master.Transport.ReadTimeout =
2000;
master.Transport.Retries =
10;
}
public bool[] ReadCoils(byte slaveAddress, ushort startAddress, ushort num) {
return master.ReadCoils(slaveAddress, startAddress, num);
}
public bool[] ReadInputs(byte slaveAddress, ushort startAddress, ushort num) {
return master.ReadInputs(slaveAddress, startAddress, num);
}
public ushort[] ReadHoldingRegisters(byte slaveAddress, ushort startAddress, ushort num) {
return master.ReadHoldingRegisters(slaveAddress, startAddress, num);
}
public ushort[] ReadInputRegisters(byte slaveAddress, ushort startAddress, ushort num) {
return master.ReadInputRegisters(slaveAddress, startAddress, num);
}
public void WriteSingleCoil(byte slaveAddress, ushort startAddress, bool value) {
master.WriteSingleCoil(slaveAddress, startAddress,
value);
}
public void WriteSingleRegister(byte slaveAddress, ushort startAddress, ushort value) {
master.WriteSingleRegister(slaveAddress, startAddress,
value);
}
public void WriteMultipleCoils(byte slaveAddress, ushort startAddress, bool[] value) {
master.WriteMultipleCoils(slaveAddress, startAddress,
value);
}
public void WriteMultipleRegisters(byte slaveAddress, ushort startAddress, ushort[] value) {
master.WriteMultipleRegisters(slaveAddress, startAddress,
value);
}
}
连接测试下载 Modbus Slave
链接：https://pan.baidu.com/s/1ydX_9KElkOTA7h-E3SIadw
提取码：7fh5
设置
连接private ModbusTCP modbus;
private void ConnectExecute(){
try {
modbus =
new ModbusTCP(IP, Port);
pollingTimer.Start();
}
catch (Exception ex)
{
Msg.Info(ex.Message);
}}
写入测试NModbus提供的对寄存器读写方法，只包括ushort类型，需要对ushort进行进行转换。
封装转换类型
public class MODBUS{
/// /// 赋值string /// /// /// /// /// public static void SetString(ushort[] src, int start, string value) {
byte[] bytesTemp = Encoding.UTF8.GetBytes(
value);
ushort[] dest = Bytes2Ushorts(bytesTemp);
dest.CopyTo(src, start);
}
/// /// 获取string /// /// /// /// /// public static string GetString(ushort[] src, int start, int len) {
ushort[] temp =
new ushort[len];
for (
int i =
0; i < len; i++)
{
temp
= src[i + start]; }
byte[] bytesTemp = Ushorts2Bytes(temp);
string res = Encoding.UTF8.GetString(bytesTemp).Trim(
new char[] {
'\0' });
return res;
}
/// /// 赋值Real类型数据 /// /// /// /// public static void SetReal(ushort[] src, int start, float value) {
byte[] bytes = BitConverter.GetBytes(
value);
ushort[] dest = Bytes2Ushorts(bytes);
dest.CopyTo(src, start);
}
/// /// 获取float类型数据 /// /// /// /// public static float GetReal(ushort[] src, int start) {
ushort[] temp =
new ushort[
2];
for (
int i =
0; i <
2; i++)
{
temp
= src[i + start]; }
byte[] bytesTemp = Ushorts2Bytes(temp);
float res = BitConverter.ToSingle(bytesTemp,
0);
return res;
}
/// /// 赋值Short类型数据 /// /// /// /// public static void SetShort(ushort[] src, int start, short value) {
byte[] bytes = BitConverter.GetBytes(
value);
ushort[] dest = Bytes2Ushorts(bytes);
dest.CopyTo(src, start);
}
/// /// 获取short类型数据 /// /// /// /// public static short GetShort(ushort[] src, int start) {
ushort[] temp =
new ushort[
1];
temp[
0] = src[start];
byte[] bytesTemp = Ushorts2Bytes(temp);
short res = BitConverter.ToInt16(bytesTemp,
0);
return res;
}
public static bool[] GetBools(ushort[] src, int start, int num) {
ushort[] temp =
new ushort[num];
for (
int i = start; i < start + num; i++)
{
temp
= src[i + start]; }
byte[] bytes = Ushorts2Bytes(temp);
bool[] res = Bytes2Bools(bytes);
return res;
}
private static bool[] Bytes2Bools(byte[] b) {
bool[] array =
new bool[
8*b.Length];
for (
int i =
0; i < b.Length; i++)
{
for (
int j =
0; j <
8; j++)
{
array[i *
8 + j] = (b
& 1) == 1;//判定byte的最后一位是否为1，若为1，则是true；否则是false b
= (byte)(b >> 1);//将byte右移一位 }
}
return array;
}
private static byte Bools2Byte(bool[] array) {
if (array !=
null && array.Length >
0)
{
byte b =
0;
for (
int i =
0; i <
8; i++)
{
if (array
) {
byte nn = (
byte)(
1 << i);
//左移一位，相当于×2 b += nn;
}
}
return b;
}
return 0;
}
private static ushort[] Bytes2Ushorts(byte[] src, bool reverse = false) {
int len = src.Length;
byte[] srcPlus =
new byte[len +
1];
src.CopyTo(srcPlus,
0);
int count = len >>
1;
if (len %
2 !=
0)
{
count +=
1;
}
ushort[] dest =
new ushort[count];
if(reverse)
{
for (
int i =
0; i < count; i++)
{
dest
= (ushort)(srcPlus[i * 2] << 8 | srcPlus[2 * i + 1] & 0xff); }
}
else {
for (
int i =
0; i < count; i++)
{
dest
= (ushort)(srcPlus[i * 2] & 0xff | srcPlus[2 * i + 1] << 8 ); }
}
return dest;
}
private static byte[] Ushorts2Bytes(ushort[] src, bool reverse = false) {
int count = src.Length;
byte[] dest =
new byte[count <<
1];
if(reverse)
{
for (
int i =
0; i < count; i++)
{
dest[i *
2] = (
byte)(src
>> 8); dest[i *
2 +
1] = (
byte)(src
>> 0); }
}
else {
for (
int i =
0; i < count; i++)
{
dest[i *
2] = (
byte)(src
>> 0); dest[i *
2 +
1] = (
byte)(src
>> 8); }
}
return dest;
}
}
根据选择的类型写入
private void WriteExecute(){
try {
if(VariableType ==
"real")
{
ushort[] buff =
new ushort[
2];
float value =
float.Parse(WriteValue);
MODBUS.SetReal(buff,
0,
value);
modbus.WriteMultipleRegisters(SlaveID, WriteAddress, buff);
}
else if(VariableType ==
"string")
{
ushort[] buff =
new ushort[
10];
MODBUS.SetString(buff,
0, WriteValue);
modbus.WriteMultipleRegisters(SlaveID, WriteAddress, buff);
}
else if(VariableType ==
"Int16")
{
ushort[] buff =
new ushort[
1];
short value =
short.Parse(WriteValue);
MODBUS.SetShort(buff,
0,
value);
modbus.WriteMultipleRegisters(SlaveID, WriteAddress, buff);
}
}
catch (Exception ex)
{
Msg.Info(ex.Message);
}}
可以看到ModbusSlave上面的数据，一个浮点型数据占用两个寄存器，4个byte。按照下图设置后，可以看到，已经写入成功。
读取测试private void ReadExecute(){
try {
if (VariableType ==
"real")
{
ushort[] buff = modbus.ReadHoldingRegisters(SlaveID, ReadAddress,
2);
float value = MODBUS.GetReal(buff,
0);
ReadValue =
value.ToString();
}
else if(VariableType ==
"string")
{
ushort[] buff = modbus.ReadHoldingRegisters(SlaveID, ReadAddress,
10);
ReadValue = MODBUS.GetString(buff,
0,
10);
}
else if(VariableType ==
"Int16")
{
ushort[] buff = modbus.ReadHoldingRegisters(SlaveID, ReadAddress,
1);
short value = MODBUS.GetShort(buff,
0);
ReadValue =
value.ToString();
}
}
catch (Exception ex)
{
Msg.Info(ex.Message);
}}
字符串写入和读取参照VariableType=="string"部分代码。
最后
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作者：Samberger
出处：cnblogs.com/Samberger/p/13039429.html
声明：网络内容，仅供学习，尊重版权，侵权速删，歉意致谢！
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