Ladder Diagram - Omron CQM1H - PROGRAM Programming Manual

instruction block
instruction execution time
instruction line
interface
interlock
interrupt (signal)
interrupt program
inverse condition
JIS
jump
jump number
ladder diagram (program)
ladder diagram symbol
ladder instruction
least-significant (bit/word)
LED
leftmost (bit/word)
link
load
560
Glossary
A group of instructions that is logically related in a ladder-diagram program. A
logic block includes all of the instruction lines that interconnect with each other
from one or more lines connecting to the left bus bar to one or more right-hand
instructions connecting to the right bus bar.
The time required to execute an instruction. The execution time for any one in-
struction can vary with the execution conditions for the instruction and the op-
erands used in it.
A group of conditions that lie together on the same horizontal line of a ladder
diagram. Instruction lines can branch apart or join together to form instruction
blocks. Also called a rung.
An interface is the conceptual boundary between systems or devices and usu-
ally involves changes in the way the communicated data is represented. Inter-
face devices perform operations like changing the coding, format, or speed of
the data.
A programming method used to treat a number of instructions as a group so
that the entire group can be reset together when individual execution is not re-
quired. An interlocked program section is executed normally for an ON execu-
tion condition and partially reset for an OFF execution condition.
A signal that stops normal program execution and causes a subroutine to be
run or other processing to take place.
A program that is executed in response to an interrupt.
See normally closed condition.
An acronym for Japanese Industrial Standards.
A type of programming where execution moves directly from one point in a pro-
gram to another, without sequentially executing any instructions in between.
A definer used with a jump that defines the points from and to which a jump is
to be made.
A form of program arising out of relay-based control systems that uses circuit-
type diagrams to represent the logic flow of programming instructions. The ap-
pearance of the program is similar to a ladder, and thus the name.
A symbol used in drawing a ladder-diagram program.
An instruction that represents the conditions on a ladder-diagram program.
The other instructions in a ladder diagram fall along the right side of the dia-
gram and are called terminal instructions.
See rightmost (bit/word).
Acronym for light-emitting diode; a device used for indicators or displays.
The highest numbered bits of a group of bits, generally of an entire word, or the
highest numbered words of a group of words. These bits/words are often called
most-significant bits/words.
A hardware or software connection formed between two Units. "Link" can refer
either to a part of the physical connection between two Units or a software con-
nection created to data existing at another location (i.e., data links).
The processes of copying data either from an external device or from a storage
area to an active portion of the system such as a display buffer. Also, an output
device connected to the PC is called a load.