Glossary
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data link area A common data area established through a data link.
data link table A table of settings kept in memory that specifies what words are to be part of a
data link for all PCs involved in the link.
data register A storage location in memory used to hold data. In CV-series PCs, data registers
are used with or without index registers to hold data used in indirect addressing.
data sharing An aspect of SYSMAC Link Systems and SYSMAC NET Link Systems in which
common data areas or common data words are created between two or more
PCs.
data transfer Moving data from one memory location to another, either within the same device
or between different devices connected via a communications line or network.
debug A process by which a draft program is corrected until it operates as intended.
Debugging includes both the removal of syntax errors, as well as the fine-tuning
of timing and coordination of control operations.
decimal A number system where numbers are expressed to the base 10. In a PC all data
is ultimately stored in binary form, four binary bits are often used to represent
one decimal digit, via a system called binary-coded decimal.
decrement Decreasing a numeric value, usually by 1.
default A value automatically set by the PC when the user does not specifically set
another value. Many devices will assume such default conditions upon the appli-
cation of power.
delimiter A code sent during communications between devices to indicate the end of the
current transmission, but not the end of the entire transmission. See terminator.
destination The location where an instruction places the data on which it is operating, as op-
posed to the location from which data is taken for use in the instruction. The loca-
tion from which data is taken is called the source.
digit A unit of storage in memory that consists of four bits.
DIP switch Dual in-line package switch, an array of pins in a signal package that is mounted
to a circuit board and is used to set operating parameters.
distributed control An automation concept in which control of each portion of an automated system
is located near the devices actually being controlled, i.e., control is decentralized
and ‘distributed’ over the system. Distributed control is a concept basic to PC
Systems.
DM Area A data area used to hold only word data. Words in the DM Area cannot be ac-
cessed bit by bit.
DM word A word in the DM Area.
downloading The process of transferring a program or data from a higher-level or host com-
puter to a lower-level or slave computer. If a Programming Device is involved,
the Programming Device is considered the host computer.
EEPROM Electrically erasable programmable read-only memory; a type of ROM in which
stored data can be erased and reprogrammed. This is accomplished using a
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