Glossary
timer
A
location in memory accessed through a TC bit and used to time down from the
timer’s set value. Timers are turned ON and reset according to their execution
conditions.
TR Area
A data area used to store execution conditions so that they can be reloaded later
for use with other instructions.
TR bit
A bit in the TR Area.
transfer
The process of moving data from one location to another within the PC, or be-
tween the PC and external devices. When data is transferred, generally a copy
of the data is sent to the destination, i.e., the content of the source of the transfer
is not changed.
transmission distance
UM area
The distance that a signal can be transmitted.
The memory area used to hold the active program, i.e., the program that is being
currently executed.
Unit
In OMRON PC terminology, the word Unit is capitalized to indicate any product
sold for a PC System. Though most of the names of these products end with the
word Unit, not all do, e.g., a Remote Terminal is referred to in a collective sense
as a Unit. Context generally makes any limitations of this word clear.
unit address
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 deter
-
mine the unit address for a CPU Bus Unit.
unit number
uploading
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 Devices is involved,
the Programming Device is considered the host computer.
watchdog timer
A timer within the system that ensures that the scan time stays within specified
limits. When limits are reached, either warnings are given or PC operation is
stopped depending on the particular limit that is reached.
WDT
See watchdog timer.
wire communications
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 per
fectly adequate for many applications.
-
word
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.
word address
word allocation
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 PC System to create an I/O Table.
work area
A part of memory containing work words/bits.
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OMRON [ OMRON ELECTRONICS LLC ]
