Allen-Bradley MicroLogix 1200 User Manual page 148

Glossary 4
Publication 1762-UM001D-EN-P - March 2004
high byte
Bits 8 to 15 of a word.
input device
A device, such as a push button or a switch, that supplies signals to
the input circuits of the controller.
inrush current
The temporary surge current produced when a device or circuit is
initially energized.
instruction
A mnemonic and data address defining an operation to be performed
by the processor. A rung in a program consists of a set of input and
output instructions. The input instructions are evaluated by the
controller as being true or false. In turn, the controller sets the output
instructions to true or false.
instruction set
The set of general purpose instructions available with a given
controller.
I/O (Inputs and Outputs)
Consists of input and output devices that provide and/or receive data
from the controller.
jump
Change in normal sequence of program execution, by executing an
instruction that alters the program counter (sometimes called a
branch). In ladder programs a JUMP (JMP) instruction causes
execution to jump to a labeled rung.
ladder logic
A program written in a format resembling a ladder-like diagram. The
program is used by a programmable controller to control devices.
least significant bit (LSB)
The digit (or bit) in a binary word (code) that carries the smallest
value of weight.