Develop Reference

read data from serialport

I am new to C# and programming in general.
I am trying to communicate with a ohmmeter which is conneted via usb to my computer.
I am able to configurate the device and even recieve data.
But i can not acces this data. I can just print it on to the console.
(Was inspired by the code on the microsoft site)
Here is the constructer of my "communication"-class where i configurate the port:
public SCPI_Commands()
{
_SerialPort.PortName = SetPortName(_SerialPort.PortName);
_SerialPort.BaudRate = 115200;
_SerialPort.Parity = Parity.None;
_SerialPort.DataBits = 8;
_SerialPort.StopBits = StopBits.One;
_SerialPort.Handshake = Handshake.None;
_SerialPort.ReadTimeout = 500;
_SerialPort.WriteTimeout = 500;
_SerialPort.Open();
_SerialPort.DataReceived += _serialPort_DataReceived;
}
Here is my function which sends a query to the device (The constant Measurment_Value represents a scpi command which is understood by my ohmmeter) :
public void get_measurement()
{
_SerialPort.WriteLine(Measurment_Value);
}
And here is the private function which checks if the device is sending data and printing it on the console (not sure how this function works) :
private void _serialPort_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
Console.WriteLine(_SerialPort.ReadLine());
}
Unfortunately i am not able to return the data as a string. My goal is to do some calculations with the received data.
Does someone has any ideas ?
Greetings from Germany.
Luke

You can read from buffer to temp byte array and then get it as string, see the below example. Put this in _serialPort_DataReceived
// this the read buffer
byte[] buff = new byte[9600];
int readByteCount = _serialPort.BaseStream.Read(buff, 0, _serialPort.BytesToRead);
// you can specify other encodings, or use default
string response = System.Text.Encoding.UTF8.GetString(buff);
Side Note
If you want to keep your sanity while working with SerialPort, always send and receive as byte array. Then, get the equivalent string using Encoding.

Sending serial command to trigger scanner Honeywell 1900

The problem is, that I can trigger scanner using Serial Port software "Hercules" sending command <SYN>T<CR><LF>, in datasheet is said to use command [SYN]T[CR] to trigger scanner, but I cant trigger it (both commands) using my serial port comunication bellow.
I get input when use scanner manually but can't trigger it... What is a problem?
(The port is virtual)
private static SerialPort port;
private static bool _continue = false;
public static void Main(string[] args)
{
port = new SerialPort();
port.PortName = "COM8";
port.BaudRate = 115200;
port.Parity = Parity.None;
port.DataBits = 8;
port.StopBits = StopBits.One;
port.Handshake = Handshake.None;
port.RtsEnable = true;
port.DtrEnable = true;
port.ReadTimeout = 500;
port.WriteTimeout = 500;
port.Open();
_continue = true;
Thread thr = new Thread(SerialPortProgram);
thr.Start();
}
private static void SerialPortProgram()
{
Console.WriteLine("Writing to port: <SYN>T<CR><LF>");
string command = "<SYN>T<CR><LF>";
port.WriteLine(command);
while (_continue)
{
try
{
string input = port.ReadLine();
Console.WriteLine("Input is - " + input);
}
catch (TimeoutException) { }
}
}

Python barcode scanner serial trigger is an article that I answered similar Python question.
The contents are shown below.
This happens because you coded the abstract expression written in the document as raw output data.
The document represents 3 bytes of data transmission.
'SYN' and 'CR' are the following hexadecimal numbers.
'SYN' = \x16
'CR' = \x0d or escape sequence \r
'T' is an ordinary ASCII character.
Whitespace and < > [ ] { } are used to delimit the data in the document, not the data to send.
And, even you need to command prefix it.
Also use Write instead of WriteLine as written by #Turbofant.
You should write like this. Please try it.
string command = "\x16M\x0d\x16T\x0d";
port.Write(command);

I guess the problem is, that you are sending the wrong command string.
The <Syn>, <CR> and <LF> stands for the special, non printable ascii characters synchronous idle, Carriage return and line feed.
You need to encode them correctly in the string
Try sending:
string command = "\x16t\r\n";
port.Write(command);
\x16is <Syn> (Because Syn is ascii character 0x16, or 22 in decimal )
\r is <CR>
\n is <LN>
And use port.Write instead of port.WriteLine, because WriteLine automatically adds the \r\n at the end of the string.

C# and serial communication how to flush the device to read same data again?

Okay so I am stuck for almost 20 days now in the same problem of a serial communication device. I have a hardware sensor which read tags and returns the tag code number on every read through serial com port 1 or 3.Any of these I use doesn't matter. I am using a program I wrote in c# to play with the incoming data.
Now problem is that if forexample:
my sensor reads tag with code "e2 0 10 1 83 10 1 23 7 0 d0 c0 1 be"
It will not read this tag again unless I switch of the sensor and turn it on again (Power reset) . So I can't figure out how to make my sensor forget all the data it read till I closed the port. ANY ONE CAN HELP PLEASE I AM DESPERATE NOW
Some one told me that we need to write to device with some commands but he didn't know more than that.
Here is the current code:
void IntializeSensor()
{
try
{
if (mySerialPort==null)
{
mySerialPort = new SerialPort("COM3");
mySerialPort.BaudRate = 9600;
mySerialPort.Parity = Parity.None;
mySerialPort.StopBits = StopBits.One;
mySerialPort.DataBits = 8;
mySerialPort.ReadTimeout = 2000;
mySerialPort.Handshake = Handshake.None;
LoglistBox.Items.Add("--Port Intilalized at COM1--");
mySerialPort.DataReceived += new SerialDataReceivedEventHandler(DataReceivedHandler);
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
void OpenPort()
{
try
{
str = "";
if (mySerialPort.IsOpen)
{
ClosePort();
Thread.Sleep(6000);
}
mySerialPort.Open();
LoglistBox.Items.Add("--Port Opened at COM1 Success--");
}
catch (Exception ex)
{
LoglistBox.Items.Add("--Port Opened Failed--Error: "+ex.Message);
}
}
void ClosePort()
{
try
{
mySerialPort.Write("ABCABCABCABCABC");
mySerialPort.DiscardInBuffer();
mySerialPort.DiscardOutBuffer();
mySerialPort.Dispose();
mySerialPort.Close();
LoglistBox.Items.Add("--Port Closed at COM1 Success--");
}
catch (Exception ex)
{
LoglistBox.Items.Add("--Port Closed Failed--Error: " + ex.Message);
MessageBox.Show(ex.Message);
}
}
private void DataReceivedHandler(object sender,SerialDataReceivedEventArgs e)
{
try
{
if (e.EventType != SerialData.Chars) return;
SerialPort COMPort = (SerialPort)sender;
int bytes = COMPort.BytesToRead;
//create a byte array to hold the awaiting data
byte[] comBuffer = new byte[bytes];
//read the data and store it
COMPort.Read(comBuffer, 0, bytes);
// System.Text.ASCIIEncoding enc = new System.Text.ASCIIEncoding();
str = ByteArrayToHexString(comBuffer);
holdfirstvalue += str;
//str = str +" "+ str;
//MessageBox.Show("after concat "+str);
if (str.Contains("FF") || str.Contains("F F") || str.Contains("F"))
{
SetText(holdfirstvalue.ToString());// ONE TAG CODE SENT TO BE SET IN LIST
str = "";
holdfirstvalue = "";
}
}
catch (Exception ex)
{
// LoglistBox.Items.Add("--Port Opened Failed--Error: " + ex.InnerException);
MessageBox.Show(ex.Message+" "+ex.InnerException);
}
}

As I understood from your comments, even the program that is shipped with it does not read the same bar-code twice in a row. Am I right?
To me it seems that "the tag reader manufacturer" may have put that mechanism intentionally to prevent user mistakenly scan an item twice at check-out. because it happens a lot that a same stays on the scanner or be crossed against the scanner couple of times when moving things around.
Unless you have access to the scanner Firmware and are able to make changes yourself, I'd say contact the manufacturer. I would contact the manufacturer and ask about this directly. There should be a command that tells the scanner to "Get out of lock mode and restart scanning again" for the special case of scanning a same item several times (e.g. buying multiple similar things.)
They should provide you with a manual with the list of all the commands you can send to your device and you use this commands to build up your system.
One more thing to try! can you scope out your serial port using "Real Term" or any other terminal monitoring application to see if the scanner sends the code to the PC after you scan the same item again or not? This helps you to isolate the problem to make sure if it is the Scanner Firmware or the desktop software. (it seems to me that it is the scanner Firmware ignoring the item because you say it works fine when you reset it)
edit: also I see you are reading your serial port based on DataREadyEvent, again, if it was me, I would add another thread with a very short delay say 20ms or 50ms to keep reading the serial port constantly. there are plenty of examples on how to implement this on the net, one simple and quick way of this is described here:
Read com ports using threading in c#
Hope it helps.

Ok so I finally found the code in hex which actually resets the sensor.
So to help anyone out there who bought Middle Range UHF RFID Reader or any type of this model.
What we did is we hacked into the wires of serial port by soldering copper wire on data pins. Then we attached the other end of those copper wires to my laptop and used the terminal reader "Putty" to see what is actually being sent by the PC to the Reader on RESET HEAD button click.
This way we found the hex code , converted it to byte array and here is the C# code to write it to reader device by serial port and resets the device:
{
mySerialPort.Open();
byte[] bytesToSend = StringToByteArray("A00265F9");// correct command to reset READER
mySerialPort.Write(bytesToSend, 0, 4);
}
public static byte[] StringToByteArray(string hex)
{
return Enumerable.Range(0, hex.Length)
.Where(x => x % 2 == 0)
.Select(x => Convert.ToByte(hex.Substring(x, 2), 16))
.ToArray();
}

Bluetooth dial with 32feet.net and c#

I am trying to provide a "click to dial" solution for someone to a bluetooth device such as a mobile phone. I have been trying to do so using the 32feet.net bluetooth api.
I haven't really done anything with bluetooth (since the days of at commands via a bluetooth serial port) but I have paired the device in question, which supports the handsfree service with the pc. I have the following code to attempt to connect and send a dial command.
String deviceAddr = "11:11:11:11:11:11";
BluetoothAddress addr = BluetoothAddress.Parse(deviceAddr);
BluetoothEndPoint rep = new BluetoothEndPoint(addr, BluetoothService.Handsfree);
BluetoothClient cli = new BluetoothClient();
cli.Connect(rep);
Stream peerStream = cli.GetStream();
String dialCmd = "ATD 0000000000\r\n";
Byte[] dcB = System.Text.Encoding.ASCII.GetBytes(dialCmd);
peerStream.Write(dcB, 0, dcB.Length);
// Begin Edit ------------------------------------------------------------
Byte[] sResponse = new Byte[100];
peerStream.Read(sResponse, 0, 99);
TextBox1.Text = System.Text.Encoding.ASCII.GetString(sResponse);
// End Edit --------------------------------------------------------------
peerStream.Close();
cli.Close();
MessageBox.Show("Done");
Since it seems to run through these lines of code, taking an appropriate time to connect at the relevant spot or crashing out if the device address is wrong and it can't connect. Obviously the AT command is not the right thing to be sending it.
Can anyone enlighten me as to what I might need to send to a bluetooth device via the handsfree profile to get it to dial?
Begin Edit -------------------------------------------
I decided to read from the stream and see if there was a response of any sort after sending the AT command through. Since I am just testing to see if I can make it work I am just dumping the response into a textbox.
The response I read from the stream is :
ERROR
There doesn't seem to be an error codes or anything.
End Edit ---------------------------------------------
Edit --------------------------------------------------
Sent command : AT+CMER\r
Result : OK
then
Sent command : AT+CIND=?\r
Result :
+CIND: ("service",(0-1)),("call",(0-1)),("callsetup",(0-3)),("battchg",(0-5)),("signal",(0-5)),("roam",(0-1)),("callheld",(0-2))
then
Send command : ATD 0000000000\r
Result:
OK
D: ("service",(0-1)),("call",(0-1)),("callsetup",(0-3)),("battchg",(0-5)),("signal",(0-5)),("roam",(0-1)),("callheld",(0-2))
Still it doesn't actually dial :(
End Edit ----------------------------------------------
Solution ----------------------------------------------
The following code now works to dial via my iPhone. It's really rough at the moment, as I have just been testing to see if I could make it work. It's enough to get started for anyone else wanting to do a similar thing.
String deviceAddr = "00:00:00:00:00:00";
BluetoothAddress addr = BluetoothAddress.Parse(deviceAddr);
BluetoothEndPoint rep = new BluetoothEndPoint(addr, BluetoothService.Handsfree);
BluetoothClient cli = new BluetoothClient();
cli.Connect(rep);
Stream peerStream = cli.GetStream();
String dialCmd1 = "AT+CMER\r";
String dialCmd2 = "AT+CIND=?\r";
String dialCmd3 = "AT+BRSF=\r";
String dialCmd4 = "ATD 0000000000;\r";
Byte[] dcB = System.Text.Encoding.ASCII.GetBytes(dialCmd1);
peerStream.Write(dcB, 0, dcB.Length);
Byte[] sRes = new Byte[200];
peerStream.Read(sRes, 0, 199);
textBox1.Text = textBox1.Text + "\n\r----------\n\r" + System.Text.Encoding.ASCII.GetString(sRes);
dcB = System.Text.Encoding.ASCII.GetBytes(dialCmd2);
peerStream.Write(dcB, 0, dcB.Length);
peerStream.Read(sRes, 0, 199);
textBox1.Text = textBox1.Text + "\n\r----------\n\r" + System.Text.Encoding.ASCII.GetString(sRes);
dcB = System.Text.Encoding.ASCII.GetBytes(dialCmd3);
peerStream.Write(dcB, 0, dcB.Length);
peerStream.Read(sRes, 0, 199);
textBox1.Text = textBox1.Text + "\n\r----------\n\r" + System.Text.Encoding.ASCII.GetString(sRes);
dcB = System.Text.Encoding.ASCII.GetBytes(dialCmd4);
peerStream.Write(dcB, 0, dcB.Length);
peerStream.Read(sRes, 0, 199);
textBox1.Text = textBox1.Text + "\n\r----------\n\r" + System.Text.Encoding.ASCII.GetString(sRes);
peerStream.Close();
cli.Close();

Try to find what is the response for AT\r (or) ATH\r.
If the response is "OK\r\n", try your dial command with no space after ATD and number.

As maintainer of 32feet.NET I'd love to find the answer to this. Hopefully someone with knowledge of HSP/HFP will explain why this doesn't work. My only general guess is that since we're not accepting/creating the SCO channel for the audio channel the phone refuses the connection.
Once thing in your case however... AT commands are terminated by a CR (0Dh); or does the semicolon act the same??

Problem with receiving data form serial port in c#?

hello i have problem with receiving data from serial port in c# in am inserting a new line operator at the end of data buffer. then i send this data buffer on serial port, after this my c# GUI receiver will take this data via Readline() function but it always give me raw data not the actual one how to resolve this problem.
//configuring the serial port this code in c# with problem
serialPort.PortName = "COM1";
serialPort.BaudRate = 9600;
serialPort.DataBits = 8;
serialPort.Parity = Parity.None;
serialPort.StopBits = StopBits.One;
//opening the serial port
if(!serialPort.IsOpen)
serialPort.Open();
//read 2byte data for msG code from serial port
string strReadData=serialPort.ReadLine();
char[] temp=new char[350];
//strReadData.CopyTo(1, temp, 0, strReadData.Length - 2);
//strReadData = temp.ToString();
//string strReadData = serialPort.ReadExisting();
//strReadData.Replace(' ', '\0');
//strReadData.Replace(' ', '');
byte[] RecievedData = Encoding.ASCII.GetBytes(strReadData);
RecievedDataDecoder(RecievedData);
//close the port
if(serialPort.IsOpen)
serialPort.Close();
but my c++ receiver is working perfectly i dont know what is the problem here is working c++ code
// variables used with the com port
BOOL m_bPortReady;
HANDLE m_hCom;
DCB m_dcb;
COMMTIMEOUTS m_CommTimeouts;
BOOL bWriteRC;
BOOL bReadRC;
DWORD iBytesWritten;
DWORD iBytesRead;
DWORD dwCommEvent;
DWORD dwRead;
char sBuffer[128];
m_hCom = CreateFile("Com1",
GENERIC_READ | GENERIC_WRITE,
0, // exclusive access
NULL, // no security
OPEN_EXISTING,
0, // no overlapped I/O
NULL); // null template
m_bPortReady = SetupComm(m_hCom, 128, 128); // set buffer sizes
m_bPortReady = GetCommState(m_hCom, &m_dcb);
m_dcb.BaudRate = 9600;
m_dcb.ByteSize = 8;
m_dcb.Parity = NOPARITY;
m_dcb.StopBits = ONESTOPBIT;
m_dcb.fAbortOnError = TRUE;
m_bPortReady = SetCommState(m_hCom, &m_dcb);
m_bPortReady = GetCommTimeouts (m_hCom, &m_CommTimeouts);
m_CommTimeouts.ReadIntervalTimeout = 50;
m_CommTimeouts.ReadTotalTimeoutConstant = 50;
m_CommTimeouts.ReadTotalTimeoutMultiplier = 10;
m_CommTimeouts.WriteTotalTimeoutConstant = 50;
m_CommTimeouts.WriteTotalTimeoutMultiplier = 10;
m_bPortReady = SetCommTimeouts (m_hCom, &m_CommTimeouts);
if (!SetCommMask(m_hCom, EV_RXCHAR))
{
printf("Error in set comm mask");
}
while(1)
{
if (WaitCommEvent(m_hCom, &dwCommEvent, NULL))
{
if (ReadFile(m_hCom, &sBuffer, 128, &iBytesRead, NULL))
printf("");
else
{
printf("Error in reading");
break;
}
}
else
{
printf("Error in Waiting");
break;
}
printf("%s",sBuffer);
strcpy(sBuffer,"");
}
CloseHandle(m_hCom);
getch();
exit(0);

Your question is a bit vague, but the ReadLine() method will return when the port receives a carriage return and line feed byte combination by default on Windows. Or \r\n, or 0x0d 0x0a if you prefer.
If the 'buffer' you are sending in the fist place contains several messages delimited by \r\n, then ReadLine() will only return the first one, then the port will close in the C# code you have posted.
Maybe your code is in a loop, but it is not shown.
Beyond that, after any data that you have received, your are converting it back to an array of bytes, determined by ASCII encoding. Are you sending ASCII in the first place? If not, it is likely that you could be missing information.
Also, if all you do is convert the received string into bytes, you could just receive the data as bytes in the first place.
I think you need to explain in a bit more detail exactly what is in the buffer you are sending, and what exactly do you receive.

Most of my serial port errors are caused by bad baude rate settings. This might be your problem too. (You can set the baude rate in some constructors of the SerialPort class, or with the BaudRate property)