codesys与C#做共享内存通信

本节在学习codesys怎样通过共享内存的方式进行与C#程序做通信
共享内存，多个进程可以对内存中的一块区域进行读写操作，达到数据交互的目的。

在共享内存使用时，需要将这个安装包SharedMemoryCommunication安装到codesys下，包文件需要的话私信联系我即可

在安装完成codesys的SharedMemoryCommunication后，就开始我们今天的学习吧

1.新建工程，然后在库管理器中添加，在高级这个选项卡。

2.在搜索框中搜索SysShm和SysTypes2 Interfaces这两个库文件

这样就添加完库了，库中具体函数的名称，在库中可以查看，也可以在百度中看到其他博主的介绍，我这就略过了哈

3.新建一个DUT，类型选择为结构，也就是说，在进行通信时，数据类型为建立的这几种类型，同样，也可以读数据的建立一个DUT，写数据的建立一个DUT，这样在共享内存时更加方便。本次实验采用了第一种方式。

TYPE DataExchange :
STRUCT
	diValue1 : DINT;
	diValue2 : DINT;
	bValue3 :BOOL;
	
END_STRUCT
END_TYPE

4.PLC程序的建立

声明变量

// This program shows how to read and write to Shared Memory.
PROGRAM PLC_PRG
VAR
	tt: Ton;
	hShMemRead: RTS_IEC_HANDLE;
	ResultRead: RTS_IEC_RESULT;
	deInstRead : DataExchange;
	ReadResult: RTS_IEC_RESULT;
	iRead: __UXINT;
	
	hShMemWrite: RTS_IEC_HANDLE;
	ResultWrite: RTS_IEC_RESULT;
	deInstWrite : DataExchange;
	WriteResult: RTS_IEC_RESULT;
	iWrite: __UXINT;
	ulSize: UDINT := SIZEOF(DataExchange);
END_VAR

在这要注意的是，共享内存的名称一定要和C#中的统一，否则就存在通信失败的情况

tt(IN := TRUE,PT:=T#2000MS);
IF tt.Q THEN				
	// Read structure from Shared Memory. 
	hShMemRead := SysSharedMemoryCreate('Test_Read', 0, ADR(ulSize), ADR(ResultRead));
	iRead := SysSharedMemoryRead(hShMemRead, 0, ADR(deInstRead), SIZEOF(deInstRead), ADR(ReadResult));
	iRead := SysSharedMemoryClose(hShm := hShMemRead);
	
	// Write structure to Shared Memory.
	hShMemWrite := SysSharedMemoryCreate('Test_Write', 0, ADR(ulSize), ADR(ResultWrite));	
	deInstWrite.diValue1 := deInstWrite.diValue1 + 2;
	deInstWrite.diValue2 := deInstWrite.diValue2 - 3;
	deInstWrite.bValue3 := TRUE;
	iWrite := SysSharedMemoryWrite(hShMemWrite, 0, ADR(deInstWrite), SIZEOF(deInstWrite), ADR(WriteResult));
	iWrite := SysSharedMemoryClose(hShm := hShMemWrite);
	
	tt(IN:=FALSE);
	tt(IN:=TRUE);
END_IF

5.为了更好的体验共享内存的效果，我们在建立可视化Visualization，这个就根据大家的喜好，建立个视图就好了。

现在我们打开VS，建立C#工程，
代码就直接拿出来了

using System;
using System.IO.MemoryMappedFiles;
using System.Runtime.InteropServices;
using System.Threading;

namespace SharedMemoryWin
{

    // Example structure for data exchange
    internal struct DataExchange
    {
        internal Int32 i1;
        internal Int32 i2;
        internal bool b1;
    }

    class Program
    {
        static void Main(string[] args)
        {
            DataExchange dataExchangeRead, dataExchangeWrite;            
            dataExchangeWrite.i1 = 0;   
            dataExchangeWrite.i2 = 0;
            dataExchangeWrite.b1 = true;


            Console.Out.WriteLine("Press 'q' to quit");

            int dataSIze = Marshal.SizeOf(typeof(DataExchange));
            
            // Open a mapped file with read access and one with write access. 
            using (var mmfRead = MemoryMappedFile.CreateOrOpen("Test_Write", dataSIze))
            using (var mmfWrite = MemoryMappedFile.CreateOrOpen("Test_Read", dataSIze))
            {
                bool quit = false;
                while (!quit)
                {
                    using (var accessorRead = mmfRead.CreateViewAccessor(0, dataSIze, MemoryMappedFileAccess.Read))
                    using (var accessorWrite = mmfWrite.CreateViewAccessor(0, dataSIze, MemoryMappedFileAccess.Write))
                    {
                        // Read the structure
                        accessorRead.Read(0, out dataExchangeRead);
                        // Write the structure
                        accessorWrite.Write(0, ref dataExchangeWrite);

                        // Display the values
                        Console.Out.Write("Read i1: {0} i2: {1} b1 {2}      Write i1: {3} i2: {4} b1 {5}\r",
                                            dataExchangeRead.i1,
                                            dataExchangeRead.i2,
                                            dataExchangeRead.b1,

                                            dataExchangeWrite.i1,
                                            dataExchangeWrite.i2,
                                            dataExchangeWrite.b1);

                        // Wait a second
                        Thread.Sleep(1000);

                        // Increment sample values
                        dataExchangeWrite.i1++;
                        dataExchangeWrite.i2--;
                        dataExchangeWrite.b1 = true;

                        // Check quit condition
                        if (Console.KeyAvailable)
                            if (Console.ReadKey().KeyChar == 'q')         
                                quit = true;
                    }
                }
            }
        }
    }
}

需要注意的是，在C#中和CODESYS中的数据类型和共享内存的名字一定要相匹配

有问题咱们一起沟通学习啊