1:串口初始化
com = new SerialPort("COM3", 9600, Parity.Even, 7, StopBits.One);
2:打开关闭串口
if (com.IsOpen)
{com.Close();}
com.Open();
if (com.IsOpen)
{ com.Close();}
3:C# ASCII转字符及字符转ASCII
public static string Chr(int asciiCode)
{ if (asciiCode >= 0 && asciiCode <= 255) { System.Text.ASCIIEncoding asciiEncoding = new System.Text.ASCIIEncoding(); byte[] byteArray = new byte[] { (byte)asciiCode }; string strCharacter = asciiEncoding.GetString(byteArray); return (strCharacter); } else { throw new Exception("ASCII Code is not valid."); }}
public static int Asc(string character)
{ if (character.Length == 1) { System.Text.ASCIIEncoding asciiEncoding = new System.Text.ASCIIEncoding(); int intAsciiCode = (int)asciiEncoding.GetBytes(character)[0]; return (intAsciiCode); } else { throw new Exception("Character is not valid."); }}
4:写入串口的命令字符串的和校验
/// <summary>
/// 和校验 /// </summary> /// <param name="data"></param> /// <returns></returns> public string SumCheck(string data) { int sum = 0; for (int i = 0; i < data.Length; i++) { sum += Asc(data.Substring(i, 1)); } string res = sum.ToString("X"); res = res.Substring(res.Length - 2, 2); return res;}
5:写入PLC
private void btnWrite_Click(object sender, EventArgs e)
{
string[] write = new string[] { "2","2"}; //将准备写入PLC的值
//将要写入的值转换成16进制数,补齐两个字节,注意高低字节需要交换 string sWriteData = ""; for (int i = 0; i < write.Length; i++) { int val = Convert.ToInt32(write[i].Length>0?write[i]:"0"); string s = val.ToString("X"); while (s.Length<4) { s = "0" + s; } sWriteData += s.Substring(2,2)+s.Substring(0,2); } MessageBox.Show(sWriteData); //写入命令,1表示写入,1194表示D202这个地址的16进制,04表示D202,D203为4个BYTE,1194=(202*2)+4096的16进制数,至于用它表示D202的起始位置,三菱故意要这么麻烦了. sWriteData = "1119404" + sWriteData + Chr(3); //chr(2)和chr(3)是构成命令的标志字符,然后加上校验和,命令组织完成 sWriteData = Chr(2) + sWriteData + SumCheck(sWriteData); MessageBox.Show(sWriteData); //写入串口 com.Write(sWriteData); //byte[] data = Encoding.ASCII.GetBytes(sWriteData); //com.Write(data,0,data.Length);}
6:读PLC
private void btnRead_Click(object sender, EventArgs e)
{ this.txtRead0.Clear(); string sReadData = "";//在读PLC中的数据之前,需要先发个指令给它,让它将数据发送到串口,下面的字符串中,chr(2),chr(3)为PLC命令的格式标志,0119404中,0表示读,1194表示D202的起始地址,04表示读D202,D203两个字,共4个字节,66为0119404和chr(3)的校验和,向串口写入"读"命令,其实和向plc地址中写入数据是一样的,只是没有数据,用0表示读
string sReadCmd = Chr(2) + "0119404" + Chr(3) + "66";
com.Write(sReadCmd); //等待1秒钟 System.Threading.Thread.Sleep(1000); // 从串口读数据 byte[] data = new byte[1024]; com.Read(data, 0, 1024); //如果首位为2,则表示数据有效.这里有个问题,在第二次读,第2位才为'2',第三次又是首位为2,需要再测试 if (data[0]==2) { string sReceiveData = System.Text.Encoding.ASCII.GetString(data); //MessageBox.Show(sReceiveData); //解析命令,将读到的字符解析成数字,注意高低位的转换 for (int i = 1; i < 8; i += 4) { string sLow = sReceiveData.Substring(i,2); string sHigh = sReceiveData.Substring(i + 2, 2); //int res = Convert.ToInt32(sHigh)+ Convert.ToInt32(sLow); int res = Convert.ToInt32(sHigh,16) + Convert.ToInt32(sLow,16); this.txtRead0.Text += res.ToString() + ","; } }