Omron CS1W-SLK11-21 - 06-2004 Manual page 194

unit address
unit number
uploading
watchdog timer
WDT
wire communications
word
word address
word allocation
work area
work bit
work word
write protect switch
write-protect
Glossary
A number used to control network communications. Unit addresses are com-
puted for Units in various ways, e.g., 10 Hex is added to the unit number to de-
termine the unit address for a CPU Bus Unit.
A number assigned to some Link Units, Special I/O Units, and CPU Bus Units
to facilitate identification when assigning words or other operating parameters.
The process of transferring a program or data from a lower-level or slave com-
puter to a higher-level or host computer. If a Programming Device is involved,
the Programming Device is considered the host computer.
A timer within the system that ensures that the scan time stays within specified
limits. When limits are reached, either warnings are given or PLC operation is
stopped depending on the particular limit that is reached.
See watchdog timer.
A communications method in which signals are sent over wire cable. Although
noise resistance and transmission distance can sometimes be a problem with
wire communications, they are still the cheapest and the most common, and
perfectly adequate for many applications.
A unit of data storage in memory that consists of 16 bits. All data areas consists
of words. Some data areas can be accessed only by words; others, by either
words or bits.
The location in memory where a word of data is stored. A word address must
specify (sometimes by default) the data area and the number of the word that
is being addressed.
The process of assigning I/O words and bits in memory to I/O Units and termi-
nals in a PLC System to create an I/O Table.
A part of memory containing work words/bits.
A bit in a work word.
A word that can be used for data calculation or other manipulation in program-
ming, i.e., a 'work space' in memory. A large portion of the IR area is always
reserved for work words. Parts of other areas not required for special purposes
may also be used as work words.
A switch used to write-protect the contents of a storage device, e.g., a floppy
disk. If the hole on the upper left of a floppy disk is open, the information on this
floppy disk cannot be altered.
A state in which the contents of a storage device can be read but cannot be
altered.
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