PCI (Peripheral Component Interconnect)
What does PCI mean?
PCI (Peripheral Component Interconnect) is an older but long-standing and widely used standard for connecting expansion cards to PCs and industrial computers. It was introduced in the early to mid-1990s and replaced older bus systems such as ISA in order to provide higher data rates, more convenience and better compatibility.
Technically, PCI is a parallel local system bus through which expansion cards communicate directly with the processor or chipset. Typical PCI plug-in cards include:
- Measurement and data acquisition cards (DAQ)
- Network cards
- Input and output cards (I/O)
- Fieldbus and interface cards (e.g. CAN, Profibus, RS-485)
- Sound and graphics cards (earlier)
The most important features of PCI include:
- Standardized slots on the mainboard (32- or 64-bit, usually 33 MHz)
- Bus widths of 32 or 64 bit and typical data rates of up to 133 MB/s (32 bit, 33 MHz)
- Plug-and-play support, i.e. automatic allocation of resources (interrupts, I/O ranges)
- Support for multiple bus master devices so that cards can transfer data independently
In industrial automation and measurement technology, PCI was an important standard for many years for expanding PCs or IPCs with modular hardware, for example for measurement, control and regulation tasks. Over time, however, PCI has increasingly been replaced by PCI Express (PCIe), which offers higher data rates, serial instead of parallel transmission and better scalability.
Despite its age, PCI can still be found in many existing systems and long-term installations. For such applications, PCI cards remain relevant, for example as replacement or expansion hardware when existing systems are being modernized but not completely replaced.