B&R MAPPC800-ENG, Руководство пользователя

Страница: 372 / 396

372
Appendix A • Glossary
Panel PC 800 User's Manual V 1.00
PCI Bus
Abbreviation for " P eripheral C omponent I nterconnect bus". Developed by Intel as an
intermediary/local bus for the latest PC generations. It is basically a synchronous bus. The main
clock of the CPU is used for synchronization. The PCI bus is microprocessor-independent, 32-
bit and 64-bit compatible, and supports both 3.3 V and 5 V cards and devices.
PCMCIA
An abbreviation for " P ersonal C omputer M emory C ard I nternational A ssociation". An association
of manufacturers and dealers who are dedicated to the cultivation and further development of
common standards for peripheral devices based on PC cards with a slot for such cards. PC
cards are mainly used for laptops, palmtops (and other portable computers), and intelligent
electronic devices. Version 1 of the PCMCIA standard was introduced in 1990.
PLC
Programmable Logic Controller; Computer-based control device that functions using an
application program. The application program is relatively easy to create using standardized
programming languages [IL, FBD, LAD, AS, ST]. Because of its serial functionality, reaction
times are slower compared to connection-oriented control. Today, PLCs are available in device
families with matched modular components for all levels of an automation hierarchy.
PnP
An abbreviation for " P lug and P lay". Specifications developed by Intel. Using Plug and Play
allows a PC to automatically configure itself so that it can communicate with peripheral devices
(e.g. monitors, modems, and printers). Users can connect a peripheral device (plug) and it
immediately runs (play) without having to manually configure the system. A Plug and Play PC
requires a BIOS that supports Plug and Play and a respective expansion card.
POH
An abbreviation for " P ower O n H ours". See MTBF.
POST
An abbreviation for " P ower- O n S elf T est". A set of routines that are stored in ROM on the
computer and that test different system components, e.g. RAM, disk drive and the keyboard in
order to determine that the connection is operating correctly and ready for operation. POST
routines notify the user of problems that occur. This is done using several signal tones or by
displaying a message that frequently accompanies a diagnosis value on the standard output or
standard error devices (generally the monitor). If the POST runs successfully, control is
transferred over to the system's bootstrap loader.
POWERLINK
See "Ethernet POWERLINK".