Glossary
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National Instruments Corporation
G-5
NI-FBUS Hardware and Software User Manual
Function block
A named block consisting of one or more input, output, and contained
parameters. The block performs some control function as its
algorithm. Function blocks are the core components you control
a system with. The Fieldbus Foundation defines standard sets of
function blocks. There are ten function blocks for the most basic
control and I/O functions. Manufacturers can define their own
function blocks.
Function Block Application
The block diagram that represents your control strategy.
H
H1
The 31.25 kbit/second type of Fieldbus.
Hard code
To permanently establish something that should be variable in a
program.
Header file
A C-language source file containing important definitions and
function prototypes.
HMI
Human-Machine Interface. A graphical user interface for the process
with supervisory control and data acquisition capability.
Host device
A computer or controller on a Fieldbus network.
Hz
Hertz.
I
I/O
Input/output.
IEC
International Electrotechnical Commission. A technical standards
committee which is at the same level as the ISO.
in.
Inches.
Index
An integer that the Fieldbus specification assigns to a Fieldbus object
or a device that you can use to refer to the object. A value in the object
dictionary used to refer to a single object.
ISA
Industry Standard Architecture.