Data transmission issue over TCP IP socket between python device and Matlab

Hi.

I can transit data between a Raspberry with python 3.7 installed and a PC with Matlab (192.168.1.40) , last release, installed by means a TCP IP Socket and configuring the Matlab PC as server and the pyhton device as client.

Here is the Pyhton client code:

 #----- A simple TCP client program in Python using send() function -----

import socket
# Create a client socket
clientSocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

# Connect to the server
clientSocket.connect(("192.168.1.40",9090))

# Send data to server
data = "HHH"
clientSocket.send(data.encode())

and this is the Matlab server code:

t = tcpip('0.0.0.0', 9090, 'NetworkRole', 'server')
fopen(t)
while true
    data = fread(t)
      end

For testing purpose I've attempted to transmit only few characters : HHH

The issue is that the transmission works but the other end (on the Matlab side) instead of the right characters (HHH) I see only their ASCII code (72, 72, 72).

If I do the same between two instances of Rasberry python (using a decode() method), I see correctly the data tranmitted over the socket.

Any idea?

Thanks in advance

Answer 1

[Shadaab Siddiqie]

From my understanding you want to know why fread returns ASCII code instead of string. This is because tcpip writes data in Unicode format thus you are using fread (which reads data form binary file). To change unicode to string use char:

u = [77 65 84 76 65 66];
c = char(u)
-> c = 'MATLAB'

Also since tcpip and its object properties will be removed. Use tcpclient and its properties instead.

[Cosimo Mercuro]

Hi Shadaab.

Thanks for you reply.

May I use

tcpclient

instead

tcpip

even if the code is a server code?

[Shadaab Siddiqie]

yes