Siemens SIMATIC Box PC 620 Manual page 199

PIC
SIMATIC programmable controller
Plug and play
Generally, a reference to the ability of a computer system to automatically confi-
gure a device added to it. When capitalized and, especially, when abbreviated PnP,
a set of specifications developed by Intel and Microsoft that allows a PC to confi-
gure itself automatically to work with peripherals such as monitors, modems, and
printers. A user can plug in a peripheral and "play" it without manually configuring
the system. A Plug and Play PC requires both a BIOS that supports Plug and Play
and a Plug and Play expansion card.
Programmable Controller
The programmable logical controllers (PLC) of the SIMATIC systems (S5 or S7)
consist of a central controller, one or more CPUs, and various I/O modules.
Pull-Down Menu
See Drop-Down Menu
R
RAM
RAM (Random Access Memory) is a read/write memory in which every memory
location can be addressed individually and its contents changed. RAM is used to
store data and programs.
ROM
ROM (Read Only Memory) is a memory in which every memory location can be
addressed individually. The stored programs and data are permanently
programmed at the factory before delivery and are not lost in the event of a power
failure.
RTC
Real-time clock
SIMATIC Box PC 620 Manual
C79000-G7076-C639-04
Glossary
Glossary-11