Omron C200H Operation Manual page 351

default
definer
delay
destination
differentiated instruction
differentiation instruction
digit
digit designator
distributed control
DM area
download
electrical noise
error code
exclusive OR
exclusive NOR
348
Glossary
A value automatically set by the PC when the user omits to set a specific val-
ue. Many devices will assume such default conditions upon the application of
power.
A number used as an operand for an instruction but that serves to define the
instruction itself, rather that the data on which the instruction is to operate.
Definers include jump numbers, subroutine numbers, etc.
In tracing, a value that specifies where tracing is to begin in relationship to
the trigger. A delay can be either positive or negative, i.e., can designate an
offset on either side of the trigger.
The location where an instruction is to place the data on which it is operating,
as opposed to the location from which data is taken for use in the instruction.
The location from which data is taken is called the source.
An instruction that is executed only once each time its execution condition
goes from OFF to ON. Nondifferentiated instructions are executed each cycle
as long as the execution condition stays ON.
An instruction used to ensure that the operand bit is never turned ON for
more than one cycle after the execution condition goes either from OFF to
ON for a Differentiate Up instruction or from ON to OFF for a Differentiate
Down instruction.
A unit of storage in memory that consists of four bits.
An operand that is used to designate the digit or digits of a word to be used
by an instruction.
An automation concept in which control of each portion of an automated sys-
tem is located near the devices actually being controlled, i.e., control is de-
centralized and 'distributed' over the system. Distributed control is one of the
fundamental concepts of PC Systems.
A data area used to hold only word data. Words in the DM area cannot be
accessed bit by bit.
The process of transferring a program or data from a higher-level computer
to a lower-level computer or PC.
Random variations of one or more electrical characteristics such as voltage,
current, and data, which might interfere with the normal operation of a de-
vice.
A numeric code generated to indicate that an error exists, and something
about the nature of the error. Some error codes are generated by the system;
others are defined in the program by the operator.
A logic operation whereby the result is true if one, and only one, of the prem-
ises is true. In ladder-diagram programming the premises are usually the ON/
OFF states of bits, or the logical combination of such states, called execution
conditions.
A logic operation whereby the result is true if both of the premises are true or
both of the premises are false. In ladder-diagram programming the premises