Image Credit: Acromag, Inc. | Data Device Corporation | Emerson

CompactPCI and PXI products are a general search form covering a wide range of peripherals for the CompactPCI / PXI bus, including switches, extenders, controllers, processors and interface adapters. Bus interfaces or adapters allow the CompactPCI / PXI system to communicate with other devices or systems. 

• Switches are used in industrial systems to connect test points or devices to instruments for the purpose of testing, measuring or monitoring the system. 
• Extenders are boards used to improve or extend the functions of the standard CompactPCI / PXI cards. 
• Controllers are special computers that are used to control the CompactPCI / PXI network.  They are used to control the data transfer between devices in the network, the status of interrupts, IRQs, registers, triggers, etc.  Also, they are used to control instruments in the network for testing and analysis.  Controllers are the most important single element in a CompactPCI / PXI system. 

CompactPCI is high performance industrial bus based on the PCI electrical specifications. Its form factor is specified to be the rugged 3U and 6U Eurocard format. PXI (PCI eXtensions for Instrumentation) is a specification developed by National Instruments that extends CompactPCI for measurements and automation systems. CompactPCI / PXI is used in many industrial applications including computer telephony, industrial automation, real-time data acquisition, real-time machine control, instrumentation, military systems, and others. Compared to desktop PCI, Compact PCI supports 8 PCI slots (the desktop PCI standard supports only 4) that can be expanded by using PCI-PCI bridges, and is more robust and sturdy for use in industrial applications.

Card Format

Card format for CompactPCI and PXI products is given in terms of (height x length).

• The height is expressed in units of 'U'.  The 'U' is a unit used for the front panel of cards.  Each 'U' is equal to 1.75 inches.  The length normally is in mm (millimeters). The most popular heights are: 3U = 100 mm and 6U = 233 mm.
• The length of the card is measured in terms of millimeters (mm). 

Types of Cards

The CompactPCI specifications recognizes two types of cards:

• A single height board, also known simply as a 3U card, is 100 mm x 160 mm with one 96 pin DIN connector (the J1connector) on the rear that plugs into the backplane. 
• A double height board, also known as a 6U card, is 233 mm x 160 mm and has a second 96 pin DIN connector (the J2 connector). 

Operating Systems

Common operating systems used by CompactPCI and PXI products include DOS, Windows® 95/98, Windows® NT, Windows® 2000, Linux, Solaris®, QNX®, VxWorks®, and LynxOS®. 

Features

Other features found on CompactPCI and PXI products include hot swappable and CE or FCC certified. 

• Hot swappable products can be plugged or unplugged when the system is running without any disturbance to the surrounding boards in the bus. 

Standards

Some cards conform with the American requirements of the Federal Communication Commission (FCC) and with the European CE Marking (Conformite Europeene or European Conformity) system, which is helpful for exports to the countries of the European Economic Area (EEA).