B&R Industries Power Panel 300, Руководство пользователя

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Appendix A • Glossary
Power Panel 300/400 User's Manual V 2.30
LCD
An abbreviation for " L iquid C rystal D isplay". A display type, based on liquid crystals that have a
polarized molecular structure and are enclosed between two transparent electrodes as a thin
layer. If an electrical field is applied to the electrodes, the molecules align themselves with the
field and form crystalline arrangements that polarize the light passing through. A polarization
filter, which is arranged using lamellar electrodes, blocks the polarized light. In this way, a cell
(pixel) containing liquid crystals can be switched on using electrode gates, thus coloring this pixel
black. Some LCD displays have an electroluminescent plate behind the LCD screen for lighting.
Other types of LCD displays can use color.
LED
An abbreviation for " L ight E mitting D iode". A semiconductor diode which converts electrical
energy into light. LEDs work on the principle of electroluminescence. They are highly efficient
because they do not produce much heat in spite of the amount of light they emit. For example,
"operational status indicators" on floppy disk drives are LEDs.
MB
Megabyte (1 MB = 220 or 1,048,576 bytes).
Microprocessor
Highly integrated circuit with the functionality of a CPU, normally housed on a single chip. It
comprises a control unit, arithmetic and logic unit, several registers and a link system for
connecting memory and peripheral components. The main performance features are the internal
and external data bus and address bus widths, the command set and the clock frequency.
Additionally, a choice can be made between CISC and RISC processors. The first commercially
available worldwide microprocessor was the Intel 4004. It came on the market in 1971.
MTBF
An abbreviation for " M ean t ime b etween f ailure". The average time which passes before a
hardware component fails and repair is needed. This time is usually expressed in thousands or
ten thousands of hours, sometimes known as power-on hours (POH).
Multitasking
Multitasking is an operating mode in an operating system that allows several computer tasks to
be executed virtually simultaneously.
Node
Branching point in a network.
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