National Instruments NI-488.2 Benutzerhandbuch
Chapter 4
Developing Your NI-488.2 Application
© National Instruments Corporation
4-9
Step 3a.
Use
ibwrt
to send the
"*IDN?"
query command to the device.
Step 3b.
Use
ibrd
to read the response from the device.
Continue communicating with the GPIB device until you are finished.
Cleanup
Step 4. Place the Device Offline before Exiting Your Application
Use
ibonl
to put the device handle offline before you exit the application.
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 file
ni488.h
,
which contains prototypes for the NI-488.2 calls and constants that you
can use in your application.
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:
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
in your application. The NI-488.2 software includes the
4882query
source
code examples to demonstrate these principles.