National Instruments NI-488.2 Benutzerhandbuch

© National Instruments Corporation

The language header file defines each of the 

ibsta

 status bits. You can test 

for an 

ibsta

 status bit being set using the bitwise 

and

 operator (

&

 in 

C/C++). For example, the 

ibsta

 ERR bit is bit 15 of 

ibsta

. 

To check for an NI-488.2 error, use the following statement after each 
NI-488.2 call:

if (ibsta & ERR)

printf("NI-488.2 error encountered");

If the ERR bit is set in 

ibsta

, an NI-488.2 error has occurred. When an 

error occurs, the error type is specified by 

iberr

. To check for an NI-488.2 

error, use the following statement after each NI-488.2 call:

if (ibsta & ERR)

printf("NI-488.2 error %d encountered", iberr);

The value in 

iberr

 is meaningful as an error type only when the ERR bit is set in 

ibsta

, indicating that an error has occurred. 

For more information about error codes and solutions, refer to Chapter 4, 

, or Appendix C, 

The count variables are updated after each read, write, or command 
function. In Win32 applications, 

ibcnt

 and 

ibcntl

 are 32-bit integers. 

On some systems, like MS-DOS, 

ibcnt

 is a 16-bit integer, and 

ibcntl

 is 

a 32-bit integer. For cross-platform compatibility, all applications should 
use 

ibcntl

. If you are reading data, the count variables indicate the 

number of bytes read. If you are sending data or commands, the count 
variables reflect the number of bytes sent.

Before you begin writing your application, you might want to use the 
Interactive Control utility to communicate with your instruments 
interactively by typing in commands from the keyboard rather than from an 
application. You can use the Interactive Control utility to learn to 
communicate with your instruments using the NI-488.2 API. For specific 
device communication instructions, refer to the user manual that came with 
your instrument. For information about using the Interactive Control utility 
and detailed examples, refer to Chapter 6,