National Instruments 600 Programming with VXI

Chapter 3 Developing Your Application

VXI/VMEpc 600 Series for Windows 95/NT 3-4

National Instruments Corporation

Alternatively, you can use VISAIC to interact with your devices. VISAIC

lists the available devices, similar to what T&M Explorer displays. By

double-clicking on a given device, you can open a VISA session and access

the device through it. For more information regarding VISAIC, use the

right-click help available from all panels.

Programming with VXI

National Instruments provides two different programming interfaces

foraccessi ng your instruments: NI-VISA and NI-VXI. NI-VISA is the

National Instruments implementation of the VISA API as defined by the

VXIplug&play standard. It is very useful when you have different types

ofinstruments in your system (such as VXI, VME, GPIB, and Serial

devices) because the NI-VISA functions have the same interface.

NI-VXI is the National Instruments proprietary interface for programming

VXI/VME instruments. Both NI-VXI and NI-VISA grant you

capability to message-based devices. With either interface you can service

asynchronous events, such as triggers and interrupts, and also assert them.

The best way to learn how to program with NI-VXI or NI-VISA is by

reviewing the example programs included in your software. In the

Examples directory you will find examples for many different types of

applications. If you are just getting started, you should first learn how to

access registers with high-level calls and send messages with word serial

functions. The NI-VISA examples of these tasks are called VISAhigh.c

and VISAws.c. The NI-VXI examples are called VXIhigh.c and

VXIws.c. You should use the other examples as you try more advanced

techniques. Consult the NI-VISA User Manual or the NI-VXI User Manual

for additional information on these topics.

Note The NI-VXI User Manual resides in the NIVXI\manuals directory, and the

NI-VISA User Manual is in the VXIpnp\

\NIvisa\manuals directory, where

would be either Win95 or WinNT. Use the Acrobat Reader program to open and

navigate through the manuals.