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matlabtcp

Matlab TCP/IP Server Sockets not sending accurate data

I am using the example from the Matlab R2019A documentation about TCP/IP connection to send data back and forth two Matlab instances over TCP.

https://www.mathworks.com/help/instrument/communicate-using-tcpip-server-sockets.html

I have a TCP client (client.m) file written as: 

    data = sin(1:64);
    plot(data);
    t = tcpip('localhost', 30000, 'NetworkRole', 'client');
    fopen(t)
    fwrite(t, data)

and a TCP server (server.m) file written as:

    t = tcpip('0.0.0.0', 30000, 'NetworkRole', 'server');
    fopen(t);
    data = fread(t, t.BytesAvailable);
    plot(data);

However, the data being sent from the client is a double array, but the data received is a integer array.

The data sent looks like the following plot: Data Sent While the data received looks like the following plot: Data Received

How can I ensure that the data that is being sent is received exactly as it is?

Solution

  • I think what you need to do, is to specify also the precision of the data being send and received (to ensure the bytes are interpreted correctly):

    % to send 
fwrite(t, data, 'double');

% to receive 1000 doubles
data = fread(t, 1000, 'double');

    This is at least what Mathworks suggests. See section Reading binary data, as well as docs for fread and fwrite.