Rockwell Automation 1747-L5xx SLC 500 Modular Hardware Style User Manual - Manual (Page 276)

Publication 1747-UM011G-EN-P - June 2008
276 Glossary
full-duplex
A high-performance protocol that allows simultaneous two-way data
transmission. For point-to-point applications only.
half-duplex
A high-performance protocol where data transmission is limited to
one direction at a time. Used in point-to-point and multi-point
applications.
hard disk
A storage device in a personal computer.
high byte
Bits 8...15 of a word.
housekeeping
The portion of the scan when the controller performs internal checks
and services communication.
initiator
A node on the DH-485 network capable of acting as a master. When
an initiator has the token it can send messages and request replies
from any node on the DH-485 network. A personal computer running
your programming software is an initiator on the data link. The
SLC 5/02, SLC 5/03, SLC 5/04, and SLC 5/05 processors can also be
initiators.
input device
A device, such as a push button or a switch, that supplies signals
through input circuits to a programmable controller.
input scan
The controller reads all input devices connected to the input
terminals.
inrush current
The temporary surge current produced when a device or circuit is
initially energized.