National Instruments 320685D-01 Easy I/O for DAQ Library, Data Acquisition Library , VXI Library , GPIB/GPIB 488.2 Library

Chapter 9 Checking for Errors in LabWindows/CVI

LabWindows/CVI Programmer Reference Manual 9-4

National Instruments Corporation

Easy I/O for DAQ Library

The Easy I/O for DAQ Library functions return a negative value when they detect an error.

They return a positive value as a warning when they are able to complete their task but not in

the way you might expect. This library uses a common set of error codes. The positive

warning codes are the same absolute values as the negative error codes. Refer to the

LabWindows/CVI Standard Libraries Reference Manual or the function panel help for a

listing of the error codes and information on the individual functions. You can use

GetDAQErrorString to get the error message associated with each Easy I/O for DAQ

Library error or warning code.

Data Acquisition Library

The Data Acquisition Library functions return a negative value when they detec t a n error.

They return a positive value as a warning when they are able to complete their task but not in

the way you might expect. This library uses a common set of error codes. The positive

warning codes are the same absolute values as the negative error codes.

Refer to the back of the NI-DAQ Function Reference Manual for PC Compatibles or the

function panel help for a listing of the error codes. You can use GetNIDAQErrorString to

get the error message associated with each Data Acquisition Library error or warning code.

VXI Library

The VXI Library uses a variety of global variables and function return codes to report any

error that occurs. You must check each function description to determine what error checking

might be necessary. Refer to the specific VXI function reference manual or the on-line help

for a listing of the error codes.

GPIB/GPIB 488.2 Library

The GPIB libraries return status information through two global variables called ibsta

andiberr.

Note If your program uses multiple threads, use the ThreadIbsta and ThreadIberr

functions in place of the ibsta and iberr global variables.

Note The GPIB Library functions return the same value that they assign to ibsta. You

can choose to use either the return values, ibsta, or ThreadIbsta.

The ERR bit within ibsta indicates an error condition. If this bit is not set, iberr does not

contain meaningful information. If the ERR bit is set in ibsta, the error condition is stored in