Timeout problem in matlab
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Hi,
I am trying to read data through serial communication in matlab
I am reading 2 bytes of data
First byte is zero for most of the times and 2nd byte contains information.
I am getting timeout error Is there any command to read data starting with zeros Warning: Unsuccessful read: A timeout occurred.
Code:
nexys = serial('COM1', 'BaudRate', 9600, 'Parity', 'odd', 'Terminator', '', 'Timeout', 1);
fopen(nexys);
myNum = 4563;
%fprintf(nexys, 'd1539'); %Fungerar
%fprintf(nexys, 'd%4d', myNum); %Fungerar
for i=1:2
fprintf(nexys, 's');
scan_s1 = fscanf(nexys,'%s')-0;
fprintf(nexys, 't');
scan_s2 = fscanf(nexys,'%s')-0;
end
Can anybody suggest something about this
Thanks Jim
2 comentarios
Matt Kindig
el 24 de Mayo de 2013
On what line is the timeout error thrown? Have you verified that the scan_s1 and scan_s2 are incorrect?
It looks like you are setting the 'Terminator' to empty. In my experience, a timeout error can arise when the device does not send a specified terminator string that Matlab recognizes. I'm not sure how it would respond with an empty terminator specified.
Respuesta aceptada
Jan
el 25 de Mayo de 2013
You try to read a string but do not define a terminator. Even the the LF terminator, the string might not be terminated, when no LF appears in the data stream. So are you sure, that FSCANF for a string is what you want?
FREAD read all values, while the import of a string might be impeded by a zero byte, because they terminate strings in C.
2 comentarios
Jan
el 26 de Mayo de 2013
@Jim: Subtracting 0 from a CHAR array converts the type to DOUBLE:
c = '123'
d = c + 0
class(d)
Alternative, which is less funky:
d = double(c);
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