Glossary
372 SPU 780 01EMAN May 2002 313
I/O Configurator A PLC internal operation that maps logic element addresses to physical I/O cards.
Also known as the Traffic Cop.
Instruction One of the programmable controller’s instruction set.
Ladder Logic A relay-based programming language typically used in programmable logic
controllers. So called because it looks vaguely like a ladder.
Ladder Logic
Documentation Text information, notes, and other descriptions of the ladder logic.
Ladder Logic
Listing A printout of a group of networks which make up a ladder logic program.
Latch A coil, the state of which is backed up in memory.
Lines Per Page The number of lines printed on a page when printing ladder logic listings.
Load To retrieve data from a disk or other source.
Loader A module that reads and writes ladder logic from a personal computer to a
programmable controller or an industrial programming terminal. It also starts and
stops a programmable controller from a personal computer.
Local I/O One of four major architectures for input/output systems (also see Distributed I/O,
Remote I/O, and Peer-to-peer Communications). The PLC and I/O modules
communicate directly through wiring from the field. For Quantum controllers, local I/
O allows a CPU, power supply, and from one through 14 I/O modules in a single
backplane (up to 448 I/O points). Local I/O is limited to a single rack and is always
head number 0. RIO and DIO processors are added in the local rack to extend the
controller’s I/O system.
Logic Editor The editor in which you edit ladder logic.
Long Comment A block of text which comme nt o n a n a ddre ss wit hin a l ad der logic program. These
are printed between the networks in the ladder listing.
LPI Lines per inch.
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