MATLAB REAL-TIME WORKSHOP 7 - TARGET LANGUAGE COMPILER Manuel d'utilisateur télécharger pdf (Page 359)

100

101

Writing and Reading Data

8-39

Note that for a given read operation, you may not know the number of bytes

returned by the device. Therefore, you may need to preset the

InputBufferSize property to a sufficiently large value before connecting the

serial port object.

As shown below, after the data is stored in the input buffer, it is then

transferred to the output variable specified by

fscanf.

Reading Text Data

You use the fgetl, fgets, and fscanf functions to read data from the device,

and format the data as text.

For example, suppose you want to return identification information for the

oscilloscope. This requires writing the

*IDN? command to the instrument, and

then reading back the result of that command.

s = serial('COM1');

fopen(s)

fprintf(s,'*IDN?')

out = fscanf(s)

out =

TEKTRONIX,TDS 210,0,CF:91.1CT FV:v1.16 TDS2CM:CMV:v1.04

By default, fscanf reads data using the %c format since the data returned by

many serial port devices is text based. However, you can specify many other

formats as described in the

fscanf reference pages.

out=fscanf(s)

...

MATLABInput Buffer

Bytes used during read

Bytes unused during read

data

1 2 ... 354 355 356 357 358 359 360 361 362 363 364 ... 407 408

Commentaires sur ces manuels

Pas de commentaire

MATLAB REAL-TIME WORKSHOP 7 - TARGET LANGUAGE COMPILER Manuel d'utilisateur Page 359

Commentaires sur ces manuels

Produits connexes et manuels pour Logiciel MATLAB REAL-TIME WORKSHOP 7 - TARGET LANGUAGE COMPILER