Sending PuTTY-like command through TCPIP or VISA

Hello all,

I am having issues with sending commands to a piece of hardware through MATLAB. I can easily PuTTY into it, and send the required commands, but when I try via MATLAB, not so much.

I initially did a system(command) to log into the device via PuTTY/Plink with echo on, and can send messages through the command window, but I wish to programattically do this. I noticed that the system function locks up matlab while it is executing, making sending any MATLAB commands impossible during the time that the system function is working.

a (somewhat) strange thing is that when I am waiting to send a command in the command window, if I highlight the command text, and hit F9, the command is sent through MATLAB into the PuTTY session.

Getting down to it - I want to send commands to my device that mimic these commands in PuTTY via TCPIP or VISA connection. I am able to successfully open a connection:

boxID = visa('ni','TCPIP0::<myIP>::<myPort>::SOCKET');
fopen(boxID);

when I send a SCPI command (box is not SCPI complient), I get a response that is a square character. I am assuming that this is the result of a response from the device.

fopen(boxID);
fprintf(boxID,'%s\n','*IDN?');
response = fscanf('boxID','%s\n');
fclose(boxID)
fprintf('Response = %s',response); % output = square shaped char

I have tried to change the *IDN? command to my commands, and they do not work. MATLAB, however, does not crash.

I am at a loss here. Anyone know how to mimic PuTTY commands in MATLAB via TCPIP or VISA? An examply command in putty is :

uv % get status
uw 0x00 % turn off

Any help is greatly appreciated.

[Walter Roberson]

Try displaying

double(output)

Answer 1

[Vinod]

If you can PuTTY into the box, then it is likely running an SSH server. Try using this:

https://www.mathworks.com/matlabcentral/fileexchange/35409

specifically the ssh2* commands in it to see if it does what you want.

[Ruger28]

Thank you for your relpy.

I attempted to run this, and it is hung on something, which I am assuming is the SSH session.

When I step through, the br.readLine() command never finishes executing. If I supress the command response this isnt an issue, but my commands get sent and they do not control my hardware. Any idea on next steps?

[Vinod]

I'd reach out to the author of the submission and see if he can give you some troubleshooting tips.