Omron CPM1

Glossary
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operating modes One of three PC modes: PROGRAM mode, MONITOR mode, and RUN mode.
operating error An error that occurs during actual PC operation as opposed to an initialization
error, which occurs before actual operations can begin.
OR A logic operation whereby the result is true if either of two premises is true, or if
both are true. In ladder-diagram programming the premises are usually ON/OFF
states of bits or the logical combination of such states called execution condi-
tions.
output The signal sent from the PC to an external device. The term output is often used
abstractly or collectively to refer to outgoing signals.
output bit A bit in the IR area that is allocated to hold the status to be sent to an output de-
vice.
output device An external device that receives signals from the PC System.
output point The point at which an output leaves the PC System. Output points correspond
physically to terminals or connector pins.
output signal A signal being sent to an external device. Generally an output signal is said to
exist when, for example, a connection point goes from low to high voltage or
from a nonconductive to a conductive state.
overflow The state where the capacity of a data storage location has been exceeded.
overseeing Part of the processing performed by the CPU that includes general tasks re-
quired to operate the PC.
overwrite Changing the content of a memory location so that the previous content is lost.
parity Adjustment of the number of ON bits in a word or other unit of data so that the
total is always an even number or always an odd number. Parity is generally
used to check the accuracy of data after being transmitted by confirming that the
number of ON bits is still even or still odd.
parity check Checking parity to ensure that transmitted data has not been corrupted.
PC See Programmable Controller.
PC configuration The arrangement and interconnections of the Units that are put together to form
a functional PC.
PC System With building-block PCs, all of the Units connected up to, but not including, the
I/O devices. The boundaries of a PC System are the PC and the program in its
CPU at the upper end; and the I/O Units at the lower end.
PCB See printed circuit board.
PC Setup A group of operating parameters set in the PC from a Programming Device to
control PC operation.
Peripheral Device Devices connected to a PC System to aid in system operation. Peripheral devic-
es include printers, programming devices, external storage media, etc.
peripheral servicing Processing signals to and from peripheral devices, including refreshing, commu-
nications processing, interrupts, etc.
port A connector on a PC or computer that serves as a connection to an external de-
vice.