C#使用S7.NET库读取和写入西门子PLC变量
前言
本来想用Wincc的接口给读和写Wincc，但是速度实在太感人了，所以不如直接读和写PLC的变量，这种方式速度瞬间快了不知道多少倍（经测试4000个变量几乎瞬间完成，应该1s左右，人感知不出来）。
网上找了好多资料，都写得比较分散。特别是关于字符串的读取和写入，写了好久才读写正常，把两种方式的代码分享出来。
使用S7.NET库读取
csharp
//使用S7.NET库___读取PLC变量
public static string[] ReadPLC(int DbAddress,int StartByteAdr,int ByteCount,int Type)
{
int i, j, k;
int types = 2;
int count;
byte[] bytes=new byte[1000];
//返回值当前设置最大1000，可自由设置
string[] result=new string[1000];
#region plc系列号+机架号+插槽号
Plc MyPLC = new Plc(CpuType.S71500, "10.168.4.2", 0, 1);
MyPLC.Open();
#endregion
//读取的是int
if (Type == 1)
{
types = 2;
}
//读取的是real
else if (Type == 2)
{
types = 4;
}
//读取的是String
else if (Type == 3)
{
types = 256;
}
//读取的是bool
else if(Type == 0)
{
types = 1;
}
try
{
j = 0;
if (types == 1)
{
//读取BOOL
for (i = 0; i < Convert.ToInt16(ByteCount / 8 + 1); i++)
{
for (k = 0; k <= 7; k++)
{
result[j + k] = MyPLC.Read("DB" + DbAddress.ToString() + "." + "DBX" + (StartByteAdr + i).ToString() + "." + k.ToString()).ToString();
if (result[j + k] == "True")
{
result[j + k] = "1";
}
else
{
result[j + k] = "0";
}
}
j = j + 8;
}
}
else if (types == 2 || types == 4)
{
//读取字节
bytes = MyPLC.ReadBytes(DataType.DataBlock, DbAddress, StartByteAdr, ByteCount * types);
for (i = 0; i <= (ByteCount * types - types); i = i + types)
{
if (types == 2)
{
result[j] = S7.Net.Types.Int.FromByteArray(bytes.Skip(i).Take(types).ToArray()).ToString();
}
if (types == 4)
{
result[j] = S7.Net.Types.Real.FromByteArray(bytes.Skip(i).Take(types).ToArray()).ToString();
}
j++;
}
}
else if (types == 256)
{
//读取字符串
//读取字符串的长度
for (i=0; i< ByteCount; i++)
{
count = (byte)MyPLC.Read(DataType.DataBlock, DbAddress, StartByteAdr+i*22 + 1, VarType.Byte, 1);
bytes = MyPLC.ReadBytes(DataType.DataBlock, DbAddress, StartByteAdr+i*22 + 2, count);
result[j] = Encoding.Default.GetString(bytes);
j++;
}
}
}
catch (Exception)
{
MessageBox.Show("错误：读取PLC变量错误！");
}
MyPLC.Close();
return result;
}使用S7.NET库写入
csharp
//使用S7.NET库___写入PLC变量
public static void WritePLC(int DbAddress, int StartByteAdr, int ByteCount, int Type, string[] strings)
{
int i,j;
short ints;
float floats;
int types = 2;
//最多1000个字节写入，可自由设置
byte[] bytes = new byte[1000];
#region plc系列号+机架号+插槽号
Plc MyPLC = new Plc(CpuType.S71500, "10.168.4.2", 0, 1);
MyPLC.Open();
#endregion
//写入的是int
if (Type == 1)
{
types = 2;
}
//写入的是real
else if (Type == 2)
{
types = 4;
}
//写入的字符串
else if (Type == 3)
{
types = 256;
}
//读取的是bool
else if (Type == 0)
{
types = 1;
}
try
{
if (types == 2)
{
for (i = 0; i <= ByteCount-1; i++)
{
ints = Convert.ToInt16(strings[i]);
MyPLC.Write(DataType.DataBlock, DbAddress, StartByteAdr + i * types, ints);
}
}
else if (types == 4)
{
for (i = 0; i <= ByteCount-1; i++)
{
floats = Convert.ToSingle(strings[i]);
MyPLC.Write(DataType.DataBlock, DbAddress, StartByteAdr + i * types, floats);
}
}
else if (types == 256)
{
for (i = 0; i <= ByteCount - 1; i++)
{
if (strings[i]!=null)
{
//字符串转换成编码再转成字节
bytes = Encoding.Default.GetBytes(strings[i]);
//写入字节长度，用字节的数据类型
MyPLC.Write(DataType.DataBlock, DbAddress, StartByteAdr + i * 22 + 1, (byte)bytes.Length);
//依次写入
MyPLC.Write(DataType.DataBlock, DbAddress, StartByteAdr + i * 22 + 2, bytes);
}
else
{
//字符串转换成编码再转成字节
bytes = Encoding.Default.GetBytes("");
//写入字节长度，用字节的数据类型
MyPLC.Write(DataType.DataBlock, DbAddress, StartByteAdr + i * 22 + 1, (byte)bytes.Length);
//依次写入
MyPLC.Write(DataType.DataBlock, DbAddress, StartByteAdr + i * 22 + 2, bytes);
}
}
}
else if (types == 1)
{
for (i=0; i <= ByteCount - 1; i=i+8)
{
for (j=0;j<=7 && i+j<= ByteCount - 1; j++)
{
if (strings[i + j]=="1")
{
MyPLC.WriteBit(DataType.DataBlock, DbAddress, StartByteAdr+i/8, j,true);
}
else
{
MyPLC.WriteBit(DataType.DataBlock, DbAddress, StartByteAdr+i/8, j, false);
}
}
}
}
}
catch (Exception)
{
MessageBox.Show("写入PLC数据错误");
}
MyPLC.Close();
}