Standalone vs. Modular: Instrumentation Bus History

Instrumentation bus technology has evolved quite a bit throughout the past 30 years. For standalone general-purpose instruments, the main bus technology during this time has been General Purpose Interface Bus (GPIB) and, to a lesser degree, RS-232, with more recent emergence of Ethernet, Universal Serial Bus (USB), and IEEE-1394 (Firewire). For modular instruments, the main choice has been VXI based upon an evolution of VME and PXI, an evolution of PCI and CompactPCI with PXI emerging as the front runner. In this article, Tim compares standalone and modular instruments and describes why his company ultimately chose PXI.