Chapter 3 Developing Your NI-488.2 Application
NI-488.2 User Manual for Windows 3-10 www.natinst.com
Applications That Use Multiple Interfaces or Communicate with Multiple GPIB Devices
This section describes items you should include in your application and
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.
•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:
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, 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, 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 0for GPIB0.