Agilent Technologies E2094S Guia do Utilizador descarregar pdf (Página 69)

Programming with VISA 3

Agilent VISA User’s Guide 69

char err_msg[1024]={0};

viStatusDesc (vi, err, err_msg);

printf ("ERROR = %s\n", err_msg);

return;

}

Example: Checking Instrument Errors When programming

instruments, it is good practice to check the instrument to ensure there

are no instrument errors after each instrument function. This example

uses a SCPI command to check a specific instrument for errors.

void system_err(){

ViStatus err;

char buf[1024]={0};

int err_no;

err=viPrintf(vi, "SYSTEM:ERR?\n");

if (err < VI_SUCCESS) err_handler (vi, err);

err=viScanf (vi, "%d%t", &err_no, &buf);

if (err < VI_SUCCESS) err_handler (vi, err);

while (err_no >0){

printf ("Error Found: %d,%s\n", err_no,

buf);

err=viScanf (vi, "%d%t", &err_no, &buf);

}

err=viFlush(vi, VI_READ_BUF);

if (err < VI_SUCCESS) err_handler (vi, err);

err=viFlush(vi, VI_WRITE_BUF);

if (err < VI_SUCCESS) err_handler (vi, err);

}

Exception Events

An alternative to trapping VISA errors by checking the return status

after each VISA call is to use the VISA exception event. On sessions

where an exception event handler is installed and

VI_EVENT_EXCEPTION is enabled, the exception event handler is

called whenever an error occurs while executing an operation.

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Agilent Technologies E2094S Guia do Utilizador Página 69