National Instruments NI-488.2 Benutzerhandbuch
Chapter 3
Developing Your NI-488.2 Application
3-10
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Applications That Use Multiple Interfaces or Communicate with
Multiple GPIB Devices
Multiple GPIB Devices
This section describes items you should include in your application and
provides general program steps with an NI-488.2 example.
provides general program steps with an NI-488.2 example.
Items to Include
Include the following items in your application:
•
Header files—In a C application, include the header files
windows.h
and
decl-32.h
. The standard Windows header file,
windows.h
,
contains definitions used by
decl-32.h
, and
decl-32.h
contains
prototypes for the NI-488.2 calls and constants that you can use in your
application.
application.
•
Error checking—Check for errors after each NI-488.2 call.
•
Error handling—Declare and define a function to handle NI-488.2
errors. This function takes the device offline and closes the application.
If the function is declared as:
errors. This function takes the device offline and closes the application.
If the function is declared as:
void gpiberr (char * msg); /*function prototype*/
Then your application invokes it as follows:
if (ibsta & ERR) {
gpiberr("NI-488.2 error");
}
General Program Steps and Examples
The following steps show you how to use the multi-device NI-488.2 calls
in your application. The NI-488.2 software includes the source code for an
example written in C,
in your application. The NI-488.2 software includes the source code for an
example written in C,
4882query.c
, and the source code for the example
written to use direct entry to access the
gpib-32.dll
,
dll4882query.c
.
The NI-488.2 software also includes a sample program written in Visual
Basic,
Basic,
query4882.frm
.
Initialization
Step 1. Become Controller-In-Charge (CIC)
Use
SendIFC
to initialize the bus and the GPIB interface so that the GPIB
interface is Controller-In-Charge (CIC). The only argument of
SendIFC
is
the GPIB interface number, typically 0 for
GPIB0
.