Glossary
Jumps in ladder diagrams are usually conditional on an execution condition;
jumps in SFC programs are conditional on the step status and transition condi
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tion status before the jump.
least-significant (bit/word)
LED
See rightmost (bit/word).
Acronym for light-emitting diode; a device used as for indicators or displays.
leftmost (bit/word)
The highest numbered bits of a group of bits, generally of an entire word, or the
highest numbered words of a group of words. These bits/words are often called
most-significant bits/words.
link
A hardware or software connection formed between two Units. “Link” can refer
either to a part of the physical connection between two Units or a software con
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nection created to data existing at another location (i.e., data links).
Link Adapter
Link System
A Unit used to connect communications lines, either to branch the lines or to con
vert between different types of cable. There are two types of Link Adapter:
Branching Link Adapters and Converting Link Adapters.
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A
system used to connect remote I/O or to connect multiple PCs in a network.
Link Systems include the following: SYSMAC BUS Remote I/O Systems, SYS
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MAC BUS/2 Remote I/O Systems, SYSMAC LINK Systems, Host Link Systems,
and SYSMAC NET Link Systems.
Link Unit
linkable slot
load
Any of the Units used to connect a PC to a Link System. These include Remote
I/O Units, SYSMAC LINK Units, and SYSMAC NET Link Units.
A
slot on either a Backplane to which a Link Unit can be mounted. Backplanes
differ in the slots to which Link Units can be mounted.
The processes of copying data either from an external device or from a storage
area to an active portion of the system such as a display buffer. Also, an output
device connected to the PC is called a load.
main line
In a Link System connected through Branching Link Adapters, the communica-
tions cable that runs from the Unit at each end of the System through the Link
Adapters.
MCR Unit
Magnetic Card Reader Unit.
megabyte
A unit of storage equal to one million bytes.
Any of the areas in the PC used to hold data or programs.
See leftmost (bit/word).
memory area
most-significant (bit/word)
nesting
Programming one loop within another loop, programming a call to a subroutine
within another subroutine, or programming an IF–ELSE programming section
within another IF–ELSE section.
Network Service Board
Network Service Unit
A
device with an interface to connect devices other than PCs to a SYSMAC NET
Link System.
A
Unit that provides two interfaces to connect peripheral devices to a SYSMAC
NET Link System.
noise interference
Disturbances in signals caused by electrical noise.
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