We Keep Coding

Send data with serial port

I want to program a rolling base. The connection of TX, RX, and GND of the base is with rs232, but I haven't this port on my laptop. So I'm using an adaptor USB-RS232. The connection works because when I enter the different commands in Putty, the robot moves.
So in visual studio, I create a serial port with this line :
SerialPort serialPort1 = new SerialPort("COM7", 115200, Parity.None, 8, StopBits.One);
After, I connect it:
try
{
serialPort1.Open();
}
catch (Exception ex)
{
MessageBox.Show("Please connect to the base");
}
So the serial port is opened. And finally, I send the buffer :
if (serialPort1.IsOpen)
{
string str = "!m 1 300";
serialPort1.Write(str);
System.Console.WriteLine(str);
}
But it doesn't work, the robot doesn't move. In Putty I enter the same command:
!m 1 300
Maybe I forget something?

It will probably be more appropriate to use serialPort1.Write(string).
If you use serialPort1.WriteLine(string) it will send a newline character after the string, which may not be expected by the device on the other end.

You're writing to the console instead of the serial port. Try this:
if (serialPort1.IsOpen)
{
string str = "!m 1 300";
serialPort1.Write(str);
}
You should also be aware of the overloads and know that the default encoding it uses is ASCII encoding.

How to read data from Mettler Toledo IND560 via Ethernet using C# socket

I'm trying to connect to Mettler Toledo IND560 scale device using c# application. Everything work fine in RS-232 connection, but it's not with Ethernet.
Following intruction in Mettler Toledo technical guide, i used HyperTerminal (port 1701) but no luck with that. It alway show connection error.
The same with C# application (Exception: No connection could be made because the target machine actively refused it 192.168.1.xx:1701).
private const int PORT_NUMBER = 1701;
private const string cmd = "user admin";
try
{
TcpClient client = new TcpClient();
client.Connect("192.168.1.11",PORT_NUMBER); //Error here
Stream stream = client.GetStream();
StreamWriter writer = new StreamWriter(stream);
StreamReader reader = new StreamReader(stream);
if (client.Connected)
{
Console.WriteLine("Connected to Mettler Toledo IDN560");
Console.WriteLine("Sending command: {0}\\n", cmd);
writer.Write($" {cmd}" + '\n');
writer.Flush();
Thread.Sleep(1000);
string str = reader.ReadLine();
Console.WriteLine(str);
}
else
{
Console.WriteLine("Error");
}
Console.ReadKey();
}
catch (Exception ex)
{
Console.WriteLine(ex);
Console.ReadKey();
}
Expected respone from device is <12 ACCESS OK> but it is not.
What is wrong here ?!

In IND560 Terminal User’s Guide it says "The InSite™ configuration tool program is used to flash new terminal softwarethrough the COM1 serial port or Ethernet port." Have you tried to connect with this program?

in my case i'm using a IND780. The command sequence is:
user USERNAME
pass PASSWORD
After both commands you can now read the weight, for example:
READ wt0101 wt0102
I've used this library:
https://www.codeproject.com/Articles/19071/Quick-tool-A-minimalistic-Telnet-library

C# Socket Listener (Server)

I have the below program that receives socket streams in form of XML and inserts them into SQL database. My problem is the following:
- When the program is launched in debug mode, all the xml streams are inserted successfully into the database.
- When it is launched normally (no debug mode), the program will insert one xml stream and miss the other (So if I had 20 streams, only 10 will be inserted).
What could be the error in this code?
client = Listener.AcceptTcpClient();
netstream = client.GetStream();
Status = "Connected to a client\n";
byte[] bytes = new byte[client.ReceiveBufferSize + 1];
netstream.Read(bytes, 0, Convert.ToInt32(client.ReceiveBufferSize));
// Return the data received from the client
string clientdata = System.Text.Encoding.ASCII.GetString(bytes);
Status="Client sent: " + clientdata ;
StorePolicy(clientdata);
Query = clientdata;
Query = Query.Replace("\0", "");
StorePolicy(Query);
Status="Received Query: " + Query;
StorePolicy("Received Query: " + Query);
netstream.Close();
client.Close();
///////////////insert into database/////////
try
{
SqlConnection conn = new SqlConnection(connectionString);
SqlCommand Cmd = new SqlCommand();
string[] words = Query.Split(new[] { "</RECORD>" }, StringSplitOptions.None);
StorePolicy(Query);
foreach (string word in words)
{
if (!string.IsNullOrEmpty(word))
{
record = word.Replace("'", "''") + "</RECORD>";
StorePolicy(record);
StrQuery = "INSERT INTO SMSListenner(XMLText) VALUES ('" + record.Replace("'", "''") + "')";
Cmd = new SqlCommand(StrQuery, conn);
conn.Open();
Cmd.ExecuteReader();
conn.Close();
StorePolicy(StrQuery);
}
}
}

MSDN clearly says:
The TcpListener class provides simple methods that listen for and
accept incoming connection requests in blocking synchronous mode.
This means once one client is connected, it blocks every other client until your "poor man web server" finished with the stream. Other clients that wait in the queue might timeout in mean time. Mind yourself that you are doing a hell of a lot to process request. This means that you will block other clients for a significant amount of time.
Also, you have no exception handling, so one client can kill your entire "server".
My advice, if it's not a student's project to learn how sockets work, use proper web server with isolation between connections, and capable of processing multiple connections at the same time.

FTPWebRequest - Active Mode with specific port

I would like to connect to a FTP-Server which works in the 'active-mode'. This means, the client can send the port number, on which the data-connection should be done. Usually this is a random port. (N > 1023)
In our case, it would be really nice, if we could always use a specific port for the connection to the FTP-Server. Something like '8232'.
Is this possible?
This is my code:
FtpWebRequest.DefaultWebProxy = null;
FtpWebRequest ftpWebRequest = (FtpWebRequest)FtpWebRequest.Create(new Uri("ftp://" + "OurDomainOfTheFTP" + "/"));
ftpWebRequest.Credentials = new NetworkCredential(this.benutzer, this.passwort);
ftpWebRequest.Timeout = 5000;
ftpWebRequest.UsePassive = false;
ftpWebRequest.Method = WebRequestMethods.Ftp.ListDirectory;
WebResponse webResponse = ftpWebRequest.GetResponse();
webResponse.Close();
Can i just write something like that?
FtpWebRequest ftpWebRequest = (FtpWebRequest)FtpWebRequest.Create(new Uri("ftp://" + "OurDomainOfTheFTP" + ":8232/"));

Unfortunately the port you supply to FtpWebRequest.Create is the command port, not the data port. In your initial example the port is omitted, causing it to default to 21.
It seems FtpWebRequest does not support specifying a port number for the data connection, see this link.
This thread contains some alternative FTP (and other protocols) clients that perhaps are able to specify this.

Set Port number when using FtpWebRequest in C#

I keep getting a exception when I try to FTP to my Win 2008 Server from C# code using VS2008 as debugger.
My test class looks like this:
public class FTP
{
private string ftpServerIP = "192.168.10.35:21";
private string ftpUserID = "Administrator";
private string ftpPassword = "XXXXXXXX";
private string uploadToFolder = "uploadtest";
public void Upload(string filename)
{
FileInfo fileInf = new FileInfo(filename);
string uri = "ftp://" + ftpServerIP + "/" + uploadToFolder + "/" + fileInf.Name;
FtpWebRequest reqFTP;
reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri(uri));
reqFTP.Credentials = new NetworkCredential(ftpUserID, ftpPassword);
reqFTP.KeepAlive = false;
reqFTP.Method = WebRequestMethods.Ftp.UploadFile;
reqFTP.UseBinary = true;
reqFTP.ContentLength = fileInf.Length;
int buffLength = 2048;
byte[] buff = new byte[buffLength];
int contentLen;
FileStream fs = fileInf.OpenRead();
try
{
Stream strm = reqFTP.GetRequestStream();
contentLen = fs.Read(buff, 0, buffLength);
while (contentLen != 0)
{
strm.Write(buff, 0, contentLen);
contentLen = fs.Read(buff, 0, buffLength);
}
strm.Close();
fs.Close();
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}
}
When I execute the code I get a Connection Failed with FTP error 227 in the GetRequestStream() call.
In the exception I can see the connection fails to: 192.168.10.35:52184
I have no idea how it comes up with port 52184.
I specify in the ftpServerIP that it should be port 21.
I have found a few persons with the same issues on google but I haven't found a good example on how this is solved and I still don't understand why it happens.
Anyone know how to handle this issue??
UPDATE:
I have tried to connect to a different FTP account and there it all works fine. Therefore I tested my 192.168.10.35:21 FTP but it works fine in CuteFTP Pro and the likes.
This just makes it even more strange..

My guess would be Windows firewall issues, FTP uses other ports than just port 21 - sometimes changing the FTP mode from active to passive helps to get things working.
reqFTP.UsePassive = false;
Look at this good article on FTP: Active FTP vs. Passive FTP, a Definitive Explanation

Thies got it right, it had to do with passive mode
The fix in the code is so insanely simple :)
reqFTP.UsePassive = false;
And it worked fast and without errors!

It is important to differentiate the COMMAND port and the DATA port. The connection protocol will also change depending if you are in ACTIVE or PASSIVE mode.
ACTIVE MODE :
1) The client initiate a connection from a random unspecified COMMAND port (N > 1023) to the default server COMMAND port (21). The client will specify his DATA port (N+1) and start listening on this port.
2) The server initiate a connection from his default DATA port (20) to specified client DATA port (N+1).
PASSIVE MODE :
1) The client initiate a connection from a random unspecified COMMAND port (N > 1023) to the default server COMMAND port (21) with the PASSIVE command. The server open a random DATA port (P > 1023) and send it to the client.
2) The client initiate a connection from his DATA port (N+1) to the specified server DATA port (P > 1023).
If you use ACTIVE mode, you will most likely need to let your client's firewall accept the connection from the server to your port (N+1 > 1024).
In your example, you were in ACTIVE mode. Your client initiated a connection from his COMMAND port (52183) to the server's default COMMAND port (21) and specified its DATA port (52184 = 52183 + 1). Then the server initiated a connection from its default DATA port (20) to the client's DATA port (52184) which was most likely rejected by the client's firewall.
I hope this helps you solve your problem!