Modbus通讯协议学习
了解了它，会使你对串口通信有一个清晰的认识！通用消息帧ASCII消息帧(在消息中的每个8Bit 字节都作为两个ASCII字符发送) 十六进制，ASCII字符0...9，A...F 消息中的每个ASCII字符都是一个十六进制字符组成每个字节的位1个起始位n个数据位，最小的有效位先发送1个奇偶校验位，无校验则无1个停止位（有校验时），2个Bit（无校验时）错误检测域LRC(纵向冗长检测) RTU 消息帧8位二进制，十六进制数0...9，A...F 消息中的每个8位域都是一个两个十六进制字符组成每个字节的位1个起始位8个数据位，最小的有效位先发送1个奇偶校验位，无校验则无1个停止位（有校验时），2个Bit（无校验时）错误检测域CRC(循环冗长检测) CRC校验
(/view/1664507.htm) public static string CRCCheck(string val)
{
val = val.TrimEnd(' ');
string[] spva = val.Split(' ');
byte[] bufData = new byte[spva.Length + 2];
bufData = ToBytesCRC(val);
ushort CRC = 0xffff;
ushort POLYNOMIAL = 0xa001;
for (int i = 0; i < bufData.Length - 2; i++)
{
CRC ^= bufData[i];
for (int j = 0; j < 8; j++)
{
if ((CRC & 0x0001) != 0)
{
CRC >>= 1;
CRC ^= POLYNOMIAL;
}
else
{
CRC >>= 1;
}
}
}
return
Maticsoft.DBUtility.HLConvert.ToHex(System.BitConverter .GetBytes(CRC));
}
/// <summary>
/// 例如把如下字符串转换成字节数组
/// AA AA AA AA 0A 00 68 00 06 03 04 54 21 28 22 E5 F3 16 BB BB BB BB 转换为字节数组
/// </summary>
/// <param name="hex">十六进制字符串
</param>
/// <returns></returns>
public static byte[] ToBytesCRC(string hex)
{
string[] temp = hex.Split(' ');
byte[] b = new byte[temp.Length + 2];
for (int i = 0; i < temp.Length; i++)
{
b[i] = Convert.ToByte(temp[i], 16);
}
return b;
}
/// <summary>
/// 将字节数据转换为十六进制字符串，中间用“ ”分割如：AA AA AA AA 0A 00 68 00 06 03 04 54 21 28 22
E5 F3 16 BB BB BB BB
/// </summary>
/// <param name="vars">要转换的字节数组</param>
/// <returns></returns>
public static String ToHex(byte[] vars)
{
return
BitConverter.ToString(vars).Replace('-', ' ').Trim();
}
CS校验(累加和)
public static string CSCheck(string str)
{
if (str.Length == 0) return "";
else str = str.Trim();
byte[] sss = ToBytes(str);
int n = 0;
for (int i = 0; i < sss.Length; i++)
{
n += sss[i];
}
return ToHex(n);
}
/// <summary>
/// AB CD 12 3B 转换为字节数组
/// </summary>
/// <param name="hex">十六进制字符串
</param>
/// <returns></returns>
public static byte[] ToBytes(string hex)
{
string[] temp = hex.Split(' ');
byte[] b = new byte[temp.Length];
for (int i = 0; i < temp.Length; i++)
{
if (temp[i].Length > 0)
b[i] = Convert.ToByte(temp[i], 16);
}
return b;
}
/// <summary>
/// 转换为符合本程序的十六进制格式
/// </summary>
/// <param name="var">1 2 3 等。
</param>
/// <returns>返回十六进制字符串，如果是1-9的话，前面带零</returns>
/// <example>例如: 5 ="05" 12 ="0C" 无论何时，都是两位数。</example>
public static string ToHex(int var)
{
int cs = var;
string tmp = "";
if (cs == 0) { tmp = "00"; }
while (cs > 0)
{
int ys;
cs = Math.DivRem(cs, 256, out ys);
tmp = tmp.Insert(0, string.Format(" {0}", Right("00" + Convert.ToString(ys, 16), 2).ToUpper()));
}
return tmp.Trim();
}
public static string Right(string str, int Length)
{
if ((Length <= 0) || (str == null))
{
return "";
}
int length = str.Length;
if (Length >= length)
{
return str;
}
return str.Substring(length - Length, Length);
}
LRC校验(LRC错误校验用于ASCII模式)
/// <summary>
/// 取模FF(255)
/// 取反+1
/// </summary>
/// <param
name="writeUncheck"></param>
/// <returns></returns>
public static string LRCheck(string writeUncheck)
{
char[] hexArray = new
char[writeUncheck.Length];
hexArray = writeUncheck.ToCharArray();
int decNum = 0, decNumMSB = 0, decNumLSB = 0;
int decByte, decByteTotal = 0;
bool msb = true;
for (int t = 0; t <=
hexArray.GetUpperBound(0); t++)
{
if ((hexArray[t] >= 48) && (hexArray[t] <= 57))
decNum = (hexArray[t] - 48);
else if ((hexArray[t] >= 65) &
(hexArray[t] <= 70))
decNum = 10 + (hexArray[t] - 65);
if (msb)
{
decNumMSB = decNum * 16;
msb = false;
}
else
{
decNumLSB = decNum;
msb = true;
}
if (msb)
{
decByte = decNumMSB + decNumLSB;
decByteTotal += decByte;
}
}
decByteTotal = (255 - decByteTotal) + 1;
decByteTotal = decByteTotal & 255;
int a, b = 0;
string hexByte = "", hexTotal = "";
double i;
for (i = 0; decByteTotal > 0; i++)
{
b =
Convert.ToInt32(System.Math.Pow(16.0, i));
a = decByteTotal % 16;
decByteTotal /= 16;
if (a <= 9)
hexByte = a.ToString();
else
{
switch (a)
{
case 10:
hexByte = "A";
break;
case 11:
hexByte = "B";
break;
case 12:
hexByte = "C";
break;
case 13:
hexByte = "D";
break;
case 14:
hexByte = "E";
break;
case 15:
hexByte = "F";
break;
}
}
hexTotal = String.Concat(hexByte, hexTotal);
}
return hexTotal;
}
public void LRCheck(byte[] code)
{
int sum = 0;
foreach (byte b in code)
{
sum += b;
}
sum = sum % 255;//取模FF(255)
sum = ~sum + 1;//取反+1
string lrc = Convert.ToString(sum, 16);
return lrc;
}