Moving stage using udp command in qt gui

[ChrisW67]

the command is as:
Header = 07 (two bytes)
FL1000
<cr> (ASCII carriage return) = 13.

This is different to your first post. Fewer zeroes.

They only have C# example in the manual which forms the send bytes as:

sendBytes[0] = 0;
sendBytes[1] = 7;
Byte[] SCLstring = Encoding.ASCII.GetBytes(“RV”);  // for sendin RV command///
// copy string to the byte array
System.Array.Copy(SCLstring, 0, sendBytes, 2, SCLstring.Length);
// insert terminator
sendBytes[sendBytes.Length - 1] = 13; // CR
// send it to the drive
udpClient.Send(sendBytes, sendBytes.Length);

sendBytes[0] = 0;
sendBytes[1] = 7;
Byte[] SCLstring = Encoding.ASCII.GetBytes(“RV”);  // for sendin RV command///
// copy string to the byte array
System.Array.Copy(SCLstring, 0, sendBytes, 2, SCLstring.Length);
// insert terminator
sendBytes[sendBytes.Length - 1] = 13; // CR
// send it to the drive
udpClient.Send(sendBytes, sendBytes.Length);

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I am no C# guru, but this looks like it overwrites the 'V' with the <CR> Unless the array is a fixed length prefilled with spaces or GetBytes() returns a trailing terminator byte and that is counted in the length. Have you tried mimicking this command?

should i create array of specific length then?

No, you should create a QByteArray of the correct length for a correct command. We have no way to know whether what you are sending is correct. That will be somewhere in the documentation for the device. I have given you a list of generic ways it may be wrong.

How can I do that...? creating in main window? can you please give me an example.
thank you

You create a QUdpSocket member variable in the main window class, exactly as d_stranz wrote. Then you use that member variable instead of creating a new local object everytime you need one. No magic involved, just C++ 101.

class MainWindow: public QMainWindow
{
  Q_OBJECT
public:
  MainWindow(QWidget *p = 0);
private:
  QUdpSocket *m_socket;
}
 
 
 
MainWindow::MainWindow(QWidget *p = 0): 
    QMainWindow(p)
{
    ...
    m_socket = new QUdpSocket(this);
}
 
// elsewhere
m_socket->writeDatagram(datagram, ...);

class MainWindow: public QMainWindow
{
  Q_OBJECT
public:
  MainWindow(QWidget *p = 0);
private:
  QUdpSocket *m_socket;
}



MainWindow::MainWindow(QWidget *p = 0): 
    QMainWindow(p)
{
    ...
    m_socket = new QUdpSocket(this);
}

// elsewhere
m_socket->writeDatagram(datagram, ...);

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