Question

我有一台使用串口连接到计算机的称重机。这是一台非常古老的机器，我们正在努力减轻它的重量并保存在数据库中机器返回的重量包含一些无效字符，例如?，重量显示为??2?0，应该是02220。

据我所知，它与网络搜索建议的结果有关。但我无法弄清楚到底是什么原因。

这是我的代码：

private void port_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
    // This method will be called when there is data waiting in the port buffer
    // Read all the data waiting in the buffer
    // string data = comport.ReadExisting();
    // Display the text to the user in the Rich Text Box
    Log(LogMsgType1.Incoming, s); 
}

public void OpenThisPort()
{
    bool error = false;

    // If the port is open, close it
    if (comport.IsOpen)
    {
        comport.Close();
    }
    else
    {
        comport.BaudRate = int.Parse("1200");
        comport.DataBits = int.Parse("8");
        comport.StopBits = StopBits.One;
        comport.Parity = Parity.None;
        comport.PortName = "COM1";
        delStart = 0;
        delLength = 9;
        comport.RtsEnable = true;
        comport.DtrEnable = true;
        comport.Encoding = System.Text.Encoding.GetEncoding(28591);
    }

如何确定将应用哪种编码？知道我在这里缺少什么吗？

Answer 1

可能不是编码问题而是硬件错误。尝试检测它：

    #region comPort_ErrorReceived
    /// <summary>
    /// This method will be called when there's data waiting in the buffer
    ///  and error occured.
    /// DisplayData is a custom method used for logging
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    void comPort_ErrorReceived(object sender, SerialErrorReceivedEventArgs e)
    {
        SerialError sr = e.EventType;
        switch (sr)
        {
            case SerialError.Frame:
                DisplayData(newLog, EventLogEntryType.Error, "On port " + comPort.PortName
                    + " the hardware detected a framing error.\n", 45);
                break;
            case SerialError.Overrun:
                DisplayData(newLog, EventLogEntryType.Error, "On port " + comPort.PortName
                    + " a character-buffer overrun has occurred. The next character is lost.\n", 46);
                break;
            case SerialError.RXOver:
                DisplayData(newLog, EventLogEntryType.Error, "On port " + comPort.PortName
                    + " an input buffer overflow has occured. There is either no room in the input buffer,"
                    + " or a character was received after the End-Of-File (EOF) character.\n", 47);
                break;
            case SerialError.RXParity:
                DisplayData(newLog, EventLogEntryType.Error, "On port " + comPort.PortName
                    + " the hardware detected a parity error.\n", 48);
                break;
            case SerialError.TXFull:
                DisplayData(newLog, EventLogEntryType.Error, "On port " + comPort.PortName
                    + " the application tried to transmit a character, but the output buffer was full.\n", 49);
                break;
            default:
                DisplayData(newLog, EventLogEntryType.Error, "On port " + comPort.PortName
                    + " an unknown error occurred.\n", 50);
                break;
        }
    }

乍一看它看起来像是框架错误，因为数据的一部分似乎是正确的。对于初学者，请确保您的电缆良好。您也可以尝试使用其他应用程序（例如putty）连接到您的设备。

同样以字节形式读取数据可能是一个好主意（然后您可以在显示之前将其转换为十六进制）。通过这种方式，您可以了解实际发送的内容。

private void port_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
int btr = comPort.BytesToRead;
byte[] comBuffer = new byte[btr];
comPort.Read(comBuffer, 0, btr);
Console.WriteLine(ByteToHex(comBuffer));
}

private string ByteToHex(byte[] comByte)
        {
            StringBuilder builder = new StringBuilder(comByte.Length * 3);
            foreach (byte data in comByte)
                builder.Append(Convert.ToString(data, 16).PadLeft(2, '0').PadRight(3, ' '));
            return builder.ToString().ToUpper();
        }

Answer 2

我遇到了同样的问题。尝试将DataBits更改为 7 ，将Parity更改为 Parity.Even ，然后它应该可以正常工作。

串口返回无效数据

2 个答案: