c#串口中缺失的数据

Question

我正在与DPS5020电源通信，以获得电压和电流。SMPS数据输出在数据包的末尾不包含任何分隔符，所以我认为它引起了问题。当我使用串行终端程序查询SMPS时，每次都得到正确的数据包，但是当我使用C#程序查询时，没有70%的数据。in数据包大小为9字节。我使用了serial_port.Read(buffer, 0, 9)，但即使如此，也存在错误。这里有人能帮我吗？我的密码在下面。

主要功能

    private void ovcRead_Click(object sender, EventArgs e)
    {
        byte[] sendbyte = power2.PowerSupply_GetOVC();   // get over current value
        try
        {   serial_pow2.Write(sendbyte, 0, sendbyte.Length);
            SMPS2_timer.Enabled = true;
            textBox2.Text = "";
        }
        catch
        {   MessageBox.Show(serial_pow2.PortName + " port error");  }
    }

    private void ser_AVDD_DataRx(object sender, SerialDataReceivedEventArgs e)
    {
        //if (SMPS2_Tick == false)
        //    return;
        //SMPS2_Tick = true;

        byte[] readb = new byte[9];
        int s = serial_pow2.Read(readb, 0, 9);

        Action Receive = () =>
        {                    
            if (power2.getOutCur == true)
            {
                decimal volt, cur;
                power2.processOCP(readb, out volt, out cur);    // process over current raw data
                power2.getOutCur = false;
                if (volt != 99.99m && cur != 99.99m)
                    textBox2.Text = volt + " V,  " + cur + " A." + ";      " + readb[0].ToString("X2") + " " + readb[1].ToString("X2") + " " + readb[2].ToString("X2") + " " + readb[3].ToString("X2") + " " + readb[4].ToString("X2") + " " + readb[5].ToString("X2") + " " + readb[6].ToString("X2") + " " + readb[7].ToString("X2") + " " + readb[8].ToString("X2");
            }
        };
        this.Invoke(new Action(Receive));
        serial_pow2.DiscardInBuffer();
    }

    private void SMPS2_timer_Tick(object sender, EventArgs e)
    {
        SMPS2_timer.Enabled = false;
        SMPS2_Tick = true;
    }

类Power2函数。

   public byte[] PowerSupply_GetOVC()
    {
        UInt16 CRC_high = 0;
        UInt16 CRC_low = 0;
        int i = 0;

        getOutCur = true;
        int[] supplySet = { 0x01, 0x03, 0x00, 0x02, 0x00, 0x02 };       // get output volt, current
        byte[] sendbyte = new byte[supplySet.Length + 2];
        Modbus_CRC_Check(supplySet, out CRC_high, out CRC_low);
        for (i = 0; i < supplySet.Length; i++)
            sendbyte[i] = Convert.ToByte(supplySet[i]);
        sendbyte[i++] = Convert.ToByte(CRC_low);
        sendbyte[i++] = Convert.ToByte(CRC_high);
        return sendbyte;
    }

    public void processOCP(byte[] readb, out decimal volt, out decimal cur)
    {
        try
        {
            int t = readb[3];
            t <<= 8;
            int y = readb[4];
            int vol = (t + y);
            volt = (decimal)vol / 100;

            t = readb[5];
            t <<= 8;
            y = readb[6];
            int curr = (t + y);
            cur = (decimal)curr / 100;
        }
        catch
        {
            volt = 99.99m;
            cur = 99.99m;
        }
    }

    void Modbus_CRC_Check(int[] data_array, out UInt16 CRC_high, out UInt16 CRC_low)
    {
        UInt16 crc = 65535;

        for (int i = 0; i < data_array.Length; i++)
        {
            crc ^= (ushort)data_array[i];
            for (int j = 0; j < 8; j++)
            {
                if ((crc & 1) != 0)
                {
                    crc >>= 1;
                    crc ^= 0xA001;
                }
                else
                {
                    crc >>= 1;
                }
            }
        }            
        CRC_low = (ushort)(crc & 0x00FF);
        CRC_high = (ushort)(crc >> 8);
    }

当使用终端时，输入和输出数据如下：

input command:      01 03 00 02 00 02 65 CB
output data :       01 03 04 00 62 00 00 5B ED

当值不正确时使用C#：

input command:   01 03 00 02 00 02 65 CB
output data1:    01 03 04 00 62 00 00 5B ED
output data2:    01 03 04 00 00 00 00 00 00
output data3:    01 00 00 00 00 00 00 00 00

我尝试设置ReadTimeout值，并在串行接收事件的开头使用计时器检查，但是结果是一样的。

Answer 1

我想我解决了。我一直怀疑程序正在接收碎片的数据。如果数据长度不是9，我将数据存储在临时缓冲区中。在下一次读取中，将最新的数据连接到串行口事件处理中的临时缓冲区。现在我得到了正确的数据。

我就是这样做的。

    private void ovcRead_Click(object sender, EventArgs e)
    {
        byte[] sendbyte = power1.PowerSupply_GetOVC();            
        try
        {   serial_pow1.Write(sendbyte, 0, sendbyte.Length);    }
        catch
        {   MessageBox.Show(serial_pow1.PortName + " port error");  }

        sendbyte = power2.PowerSupply_GetOVC();
        try
        {   serial_pow2.Write(sendbyte, 0, sendbyte.Length);
            query = true;
            textBox2.Text = "";
        }
        catch
        {   MessageBox.Show(serial_pow2.PortName + " port error");  }
    }

    byte[] readb = new byte[100];
    int cnt = 0;
    int prevlen = 0;
    int newlen = 0;

    private void ser_AVDD_DataRx(object sender, SerialDataReceivedEventArgs e)
    {          

        int bytes = serial_pow2.BytesToRead;
        byte[] readc = new byte[bytes];
        serial_pow2.Read(readc, 0, bytes);
        if (bytes < 9)
        {
            if (query == true)
            {
                readc.CopyTo(readb, 0);
                prevlen = readc.Length;
                query = false;
            }
            else
            {
                try
                {
                    readc.CopyTo(readb, prevlen);
                    newlen = prevlen + readc.Length;
                }
                catch (Exception ex)
                {
                    MessageBox.Show(readc.Length + "/n" + ex.Message);
                }
            }
        }
        else
        {
            readc.CopyTo(readb, 0);
        }
        Action Receive = () =>
        {
            if (readc.Length == 9)
            {
                prevlen = 0;
                cnt = 0;
                decimal volt, cur;
                power2.processOCP(readc, out volt, out cur);
                power2.getOutCur = false;
                textBox2.Text = volt + " V,  " + cur + " A." + ";      " + readb[0].ToString("X2") + " " + readb[1].ToString("X2") + " " + readb[2].ToString("X2") + " " + readb[3].ToString("X2") + " " + readb[4].ToString("X2") + " " + readb[5].ToString("X2") + " " + readb[6].ToString("X2") + " " + readb[7].ToString("X2") + " " + readb[8].ToString("X2");
                //if (volt != 99.99m && cur != 99.99m)                        
            }
            else
            {
                textBox2.Text = "";
                byte[] temp = new byte[newlen];

                for (int b = 0; b < newlen; b++)
                {
                    textBox2.Text += readb[b].ToString("X2") + " ";
                }
            }
        };
        this.Invoke(new Action(Receive));            
    }

Answer 2

这个问题可能是由serial_pow2.DiscardInBuffer()引起的。

除非您知道缓冲区中不需要数据，否则不要丢弃它。

如果您发出两个请求而只读取一个响应，serial_pow2.DiscardInBuffer()将在缓冲区中丢弃第二个响应。

由于您的代码片段是由按钮初始化的，我无法保证您如何提出请求并获得响应。

我的建议是不使用DiscardInBuffer，除非您正在初始化或关闭应用程序，否则可能会丢失数据。