Servo Controller and Matlab

Confused

I've been trying to figure out how to controll the servos using matlab and its COM interface.
What I whant to do is basically set the positions of the servos.

I get the basic ideas of the COM "language" like:

s = serial('COM3');
set(s,'BaudRate',2400);
fopen(s);
fprintf(s,'!SCVER?')
out = fscanf(s);
fclose(s)
delete(s)
clear s
But even the above doesn't seem to work properly.

If anyone has a good link, a good explanation·or some example code that would be much appreciated.
Thanks!

Confused

Btw.. I've tried to search in the forum for answers but I haven't found any.

Paul Baker

The thing that stands out to me is you didn't include the carriage return ($0D) which is required after all commands. For C syntax (which the matlab code you use seems to emulate), /r after the command should produce the character.

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1+1=10

Confused

Thanks for the reply!

I have changed the Terminator for the COM object to CR because the default is LF. However:

fprintf(s,'!SCVER?')
fprintf(s,'/r')

out = fscanf(s)
out = !SCVER?

-> So after I scan the buffer it contains "!SCVER?"

out = fscanf(s)
out = 1.4/r

-> If I scan it again I get the above
This doesn't seem right

Confused

Btw I think it's '\r' that's the Carrige Return not '/r'. This gives the same result as above with the change of the "\"

Paul Baker

oh yes your correct, its a backslash. I think you are getting a loopback of what you are sending out, I think the 1.4 is the answer you are looking for. I suggest reading the helpfiles for Matlab's com library, there may be a means for switching the loopback off. I can't be much assistance beyond this since I haven't worked with Matlab in nearly 5 years.

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1+1=10

Confused

Anyone that has some examples of code that can be used in Matlab for the actual positioning of the servos or other information to help me?