我要评论modbus协议时应用于电子控制器上的一种通用语言。通过此协议，控制器相互之间、控制器经由网络/串口和其它设备之间可以进行通信。它已经成为了一种工业标准。有了这个通信协议，不同的厂商生成的控制设备就可以连城工业网络，进行集中监控。
本文实现需要借用一个开源的nmodbus库来完成，通过在菜单栏，工具-----nuget包管理器-----管理解决方案的nuget程序包，安装nmodbus的开源库。
本次实例的基本框架和实现效果如下所示：
可自动识别当前设备的可用串口。
modbus rtu通信的具体的实现如下：
using system;
using system.collections;
using system.collections.generic;
using system.componentmodel;
using system.data;
using system.drawing;
using system.linq;
using system.text;
using system.threading.tasks;
using system.windows.forms;
using modbus.device;
using system.net.sockets;
using system.threading;
using system.io.ports;
using system.drawing.text;
using system.windows.forms.visualstyles;
using system.timers;
using system.codedom.compiler;
namespace modbusrtumaster
{
public partial class form1 : form
{
#region 参数配置
private static imodbusmaster master;
private static serialport port;
//写线圈或写寄存器数组
private bool[] coilsbuffer;
private ushort[] registerbuffer;
//功能码
private string functioncode;
//功能码序号
private int functionoder;
//参数(分别为从站地址,起始地址,长度)
private byte slaveaddress;
private ushort startaddress;
private ushort numberofpoints;
//串口参数
private string portname;
private int baudrate;
private parity parity;
private int databits;
private stopbits stopbits;
//自动测试标志位
private bool autoflag = false;
//获取当前时间
private system.datetime current_time;
//定时器初始化
private system.timers.timer t = new system.timers.timer(1000);
private const int wm_device_change = 0x219; //设备改变
private const int dbt_devicearrival = 0x8000; //设备插入
private const int dbt_device_remove_complete = 0x8004; //设备移除
#endregion
public form1()
{
initializecomponent();
getseriallsttb1();
}
private void form1_load(object sender, eventargs e)
{
//界面初始化
cmb_portname.selectedindex = 0;
cmb_baud.selectedindex = 5;
cmb_parity.selectedindex = 2;
cmb_databbits.selectedindex = 1;
cmb_stopbits.selectedindex = 0;
}
#region 定时器
//定时器初始化,失能状态
private void init_timer()
{
t.elapsed += new system.timers.elapsedeventhandler(execute);
t.autoreset = true;//设置false定时器执行一次，设置true定时器一直执行
t.enabled = false;//定时器使能true，失能false
//t.start();
}
private void execute(object source,system.timers.elapsedeventargs e)
{
//停止定时器后再打开定时器，避免重复打开
t.stop();
//executefunction();可添加执行操作
t.start();
}
#endregion
#region 串口配置
/// <summary>
/// 串口参数获取
/// </summary>
/// <returns></返回串口配置参数>
private serialport initserialportparameter()
{
if (cmb_portname.selectedindex < 0 || cmb_baud.selectedindex < 0 || cmb_parity.selectedindex < 0 || cmb_databbits.selectedindex < 0 || cmb_stopbits.selectedindex < 0)
{
messagebox.show("请选择串口参数");
return null;
}
else
{
portname = cmb_portname.selecteditem.tostring();
baudrate = int.parse(cmb_baud.selecteditem.tostring());
switch (cmb_parity.selecteditem.tostring())
{
case "奇":
parity = parity.odd;
break;
case "偶":
parity = parity.even;
break;
case "无":
parity = parity.none;
break;
default:
break;
}
databits = int.parse(cmb_databbits.selecteditem.tostring());
switch (cmb_stopbits.selecteditem.tostring())
{
case "1":
stopbits = stopbits.one;
break;
case "2":
stopbits = stopbits.two;
break;
default:
break;
}
port = new serialport(portname, baudrate, parity, databits, stopbits);
return port;
}
}
#endregion
#region 串口收/发
private async void executefunction()
{
current_time = system.datetime.now;
try
{
if (port.isopen == false)
{
port.open();
}
if (functioncode != null)
{
switch (functioncode)
{
case "01 read coils"://读取单个线圈
setreadparameters();
try
{
coilsbuffer = master.readcoils(slaveaddress, startaddress, numberofpoints);
}
catch(exception)
{
messagebox.show("参数配置错误");
//messagebox.show(e.message);
autoflag = false;
break;
}
setmsg("[" + current_time.tostring("yyyy-mm-dd hh:mm:ss" + "]" + " "));
for (int i = 0; i < coilsbuffer.length; i++)
{
setmsg(coilsbuffer[i] + " ");
}
setmsg("\r\n");
break;
case "02 read discrete inputs"://读取输入线圈/离散量线圈
setreadparameters();
try
{
coilsbuffer = master.readinputs(slaveaddress, startaddress, numberofpoints);
}
catch(exception)
{
messagebox.show("参数配置错误");
autoflag = false;
break;
}
setmsg("[" + current_time.tostring("yyyy-mm-dd hh:mm:ss" + "]" + " "));
for (int i = 0; i < coilsbuffer.length; i++)
{
setmsg(coilsbuffer[i] + " ");
}
setmsg("\r\n");
break;
case "03 read holding registers"://读取保持寄存器
setreadparameters();
try
{
registerbuffer = master.readholdingregisters(slaveaddress, startaddress, numberofpoints);
}
catch (exception)
{
messagebox.show("参数配置错误");
autoflag = false;
break;
}
setmsg("[" + current_time.tostring("yyyy-mm-dd hh:mm:ss" + "]" + " "));
for (int i = 0; i < registerbuffer.length; i++)
{
setmsg(registerbuffer[i] + " ");
}
setmsg("\r\n");
break;
case "04 read input registers"://读取输入寄存器
setreadparameters();
try
{
registerbuffer = master.readinputregisters(slaveaddress, startaddress, numberofpoints);
}
catch (exception)
{
messagebox.show("参数配置错误");
autoflag = false;
break;
}
setmsg("[" + current_time.tostring("yyyy-mm-dd hh:mm:ss" + "]" + " "));
for (int i = 0; i < registerbuffer.length; i++)
{
setmsg(registerbuffer[i] + " ");
}
setmsg("\r\n");
break;
case "05 write single coil"://写单个线圈
setwriteparametes();
await master.writesinglecoilasync(slaveaddress, startaddress, coilsbuffer[0]);
break;
case "06 write single registers"://写单个输入线圈/离散量线圈
setwriteparametes();
await master.writesingleregisterasync(slaveaddress, startaddress, registerbuffer[0]);
break;
case "0f write multiple coils"://写一组线圈
setwriteparametes();
await master.writemultiplecoilsasync(slaveaddress, startaddress, coilsbuffer);
break;
case "10 write multiple registers"://写一组保持寄存器
setwriteparametes();
await master.writemultipleregistersasync(slaveaddress, startaddress, registerbuffer);
break;
default:
break;
}
}
else
{
messagebox.show("请选择功能码!");
}
port.close();
}
catch (exception ex)
{
port.close();
messagebox.show(ex.message);
}
}
#endregion
/// <summary>
/// 设置读参数
/// </summary>
private void setreadparameters()
{
if (txt_startaddr1.text == "" || txt_slave1.text == "" || txt_length.text == "")
{
messagebox.show("请填写读参数!");
}
else
{
slaveaddress = byte.parse(txt_slave1.text);
startaddress = ushort.parse(txt_startaddr1.text);
numberofpoints = ushort.parse(txt_length.text);
}
}
/// <summary>
/// 设置写参数
/// </summary>
private void setwriteparametes()
{
if (txt_startaddr2.text == "" || txt_slave2.text == "" || txt_data.text == "")
{
messagebox.show("请填写写参数!");
}
else
{
slaveaddress = byte.parse(txt_slave2.text);
startaddress = ushort.parse(txt_startaddr2.text);
//判断是否写线圈
if (functionoder == 4 || functionoder == 6)
{
string[] strarr = txt_data.text.split(' ');
coilsbuffer = new bool[strarr.length];
//转化为bool数组
for (int i = 0; i < strarr.length; i++)
{
// strarr[i] == "0" ? coilsbuffer[i] = false : coilsbuffer[i] = true;
if (strarr[i] == "0")
{
coilsbuffer[i] = false;
}
else
{
coilsbuffer[i] = true;
}
}
}
else
{
//转化ushort数组
string[] strarr = txt_data.text.split(' ');
registerbuffer = new ushort[strarr.length];
for (int i = 0; i < strarr.length; i++)
{
registerbuffer[i] = ushort.parse(strarr[i]);
}
}
}
}
/// <summary>
/// 创建委托，打印日志
/// </summary>
/// <param name="msg"></param>
public void setmsg(string msg)
{
richtextbox1.invoke(new action(() => { richtextbox1.appendtext(msg); }));
}
/// <summary>
/// 清空日志
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void button2_click(object sender, eventargs e)
{
richtextbox1.clear();
}
/// <summary>
/// 单击button1事件，串口完成一次读/写操作
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void button1_click(object sender, eventargs e)
{
//autoflag = false;
//button_automatictest.enabled = true;
try
{
//初始化串口参数
initserialportparameter();
master = modbusserialmaster.creatertu(port);
executefunction();
}
catch (exception)
{
messagebox.show("初始化异常");
}
}
/// <summary>
/// 自动测试初始化
/// </summary>
private void automatictest()
{
autoflag = true;
button1.enabled = false;
initserialportparameter();
master = modbusserialmaster.creatertu(port);
task.factory.startnew(() =>
{
//初始化串口参数
while (autoflag)
{
try
{
executefunction();
}
catch (exception)
{
messagebox.show("初始化异常");
}
thread.sleep(500);
}
});
}
/// <summary>
/// 读取数据时，失能写数据；写数据时，失能读数据
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void combobox1_selectedindexchanged(object sender, eventargs e)
{
if (combobox1.selectedindex >= 4)
{
groupbox2.enabled = true;
groupbox1.enabled = false;
}
else
{
groupbox1.enabled = true;
groupbox2.enabled = false;
}
//委托事件,在主线程中创建的控件，在子线程中读取设置控件的属性会出现异常，使用invoke方法可以解决
combobox1.invoke(new action(() => { functioncode = combobox1.selecteditem.tostring(); functionoder = combobox1.selectedindex; }));
}
/// <summary>
/// 将打印日志显示到最新接收到的符号位置
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void richtextbox1_textchanged(object sender, eventargs e)
{
this.richtextbox1.selectionstart = int.maxvalue;
this.richtextbox1.scrolltocaret();
}
/// <summary>
/// 自动化测试
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void button_automatictest_click(object sender, eventargs e)
{
autoflag = false;
button_automatictest.enabled = false; //自动收发按钮失能，避免从复开启线程
if (autoflag == false)
{
automatictest();
}
}
/// <summary>
/// 串口关闭，停止读/写
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void button_closeport_click(object sender, eventargs e)
{
autoflag = false;
button1.enabled = true;
button_automatictest.enabled = true;
t.enabled = false;//失能定时器
if (port.isopen)
{
port.close();
}
}
#region 串口下拉列表刷新
/// <summary>
/// 刷新下拉列表显示
/// </summary>
private void getseriallsttb1()
{
//清除cmb_portname显示
cmb_portname.selectedindex = -1;
cmb_portname.items.clear();
//获取串口列表
string[] seriallst = serialport.getportnames();
if (seriallst.length > 0)
{
//取串口进行排序
array.sort(seriallst);
//将串口列表输出到cmb_portname
cmb_portname.items.addrange(seriallst);
cmb_portname.selectedindex = 0;
}
}
/// <summary>
/// 消息处理
/// </summary>
/// <param name="m"></param>
protected override void wndproc(ref message m)
{
switch (m.msg) //判断消息类型
{
case wm_device_change: //设备改变消息
{
getseriallsttb1(); //设备改变时重新花去串口列表
}
break;
}
base.wndproc(ref m);
}
#endregion
private void label11_click(object sender, eventargs e)
{
}
private void txt_slave1_textchanged(object sender, eventargs e)
{
}
private void label7_click(object sender, eventargs e)
{
}
private void txt_startaddr1_textchanged(object sender, eventargs e)
{
}
private void label8_click(object sender, eventargs e)
{
}
private void txt_length_textchanged(object sender, eventargs e)
{
}
}
}在线程中对控件的属性进行操作可能会出现代码异常，可以使用invoke委托方法完成相应的操作：
public void setmsg(string msg)
{
richtextbox1.invoke(new action(() => { richtextbox1.appendtext(msg); }));
}在进行自动读/写操作时，为避免多次点击按键控件，多次重复建立新线程；在进入自动读写线程中时，将对应的按键控件失能，等待停止读写操作时再使能：
private void automatictest()
{
autoflag = true;
button1.enabled = false;
initserialportparameter();
master = modbusserialmaster.creatertu(port);
task.factory.startnew(() =>
{
//初始化串口参数
while (autoflag)
{
try
{
executefunction();
}
catch (exception)
{
messagebox.show("初始化异常");
}
thread.sleep(500);
}
});
}自动获取当前设备的可用串口实现如下：
#region 串口下拉列表刷新
/// <summary>
/// 刷新下拉列表显示
/// </summary>
private void getseriallsttb1()
{
//清除cmb_portname显示
cmb_portname.selectedindex = -1;
cmb_portname.items.clear();
//获取串口列表
string[] seriallst = serialport.getportnames();
if (seriallst.length > 0)
{
//取串口进行排序
array.sort(seriallst);
//将串口列表输出到cmb_portname
cmb_portname.items.addrange(seriallst);
cmb_portname.selectedindex = 0;
}
}
/// <summary>
/// 消息处理
/// </summary>
/// <param name="m"></param>
protected override void wndproc(ref message m)
{
switch (m.msg) //判断消息类型
{
case wm_device_change: //设备改变消息
{
getseriallsttb1(); //设备改变时重新花去串口列表
}
break;
}
base.wndproc(ref m);
}
#endregion对本次实例进行测试需要使用到串口模拟软件，串口模拟器可以到网上下载
modbus从站需要完成一下两步操作：
一、菜单栏connection-----connect
二、菜单栏setup-----slave definition
最后需要运行自己创建的modbus rtu master上位机，完成相应的配置：
实现的最终效果：
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