National Instruments GPIB-PC - Manual (Page 44)

©National Instruments Corp. 3-1 GPIB-PC User Manual
Section Three - GPIB-PC
Functions — Introduction
This section introduces you to the GPIB-PC handler functions and their
capabilities. They are described in the order you will most likely use
them.
Application environments for which the functions are designed are
described. Short examples illustrate how the functions operate.
Introduction to the GPIB-PC Functions
The GPIB-PC functions are high-level and low-level functions that
communicate with and control devices on the GPIB. The functions are
divided into six groups, and each group is distinguished by the type of
applications it serves. The functions contained in the first three groups
are mostly high-level, while those of the last three are mostly low-level.
High-Level Functions
High-level functions are easy to learn and use. They automatically
execute sequences of commands that handle bus management
operations required to perform activities such as reading from and
writing to devices and polling them for status. These functions free you
from having to know the GPIB protocol or bus management details
involved. Most device functions (functions that specify a device) are
high-level functions.
Low-Level Functions
In contrast, low-level functions perform rudimentary or primitive
operations that require that you know something about GPIB protocol to
use them effectively. They are needed because high-level functions do
not always meet the requirements of applications. In such cases, low-
level functions offer the flexibility you need to solve most of your
application problems. All board functions (functions that specify a
board) are low-level functions.
Calling Syntax
The calling syntax for GPIB-PC functions varies according to the
language used. In this section, a generic syntax is used to identify the
function and its arguments.