VXIbus

VXIbus
Name	VXIbus
Caption	VXI mainframe with modules
Invented	1987
Makers	VXIbus Consortium
Type	Instrumentation bus

VXIbus

VXIbus is an open standard instrumentation bus used for modular electronic test and measurement systems. It combines extensions of the VMEbus backplane with standardized signal conditioning and instrumentation features developed by organizations such as National Instruments, Tektronix, and Agilent Technologies. VXIbus systems are deployed across industries including aerospace, automotive, and telecommunications where interoperability with PXI, GPIB, and SCPI-controlled instruments is important.

Overview

VXIbus provides a modular chassis-based platform that integrates controller blades, measurement modules, and power supplies from vendors like Rohde & Schwarz, Keysight Technologies, Advantest, Anritsu, and LeCroy. The standard defines mechanical, electrical, and software aspects enabling compatibility among products from Keithley Instruments, Siemens, Honeywell, Thales Group, and BAE Systems. VXIbus supports high-channel-count automated test equipment (ATE) used by organizations such as NASA, European Space Agency, Boeing, and Airbus. It complements standards endorsed by bodies including IEEE, VITA, and the IEC.

History and Development

The VXIbus initiative emerged in the mid-1980s when companies like Hewlett-Packard (later divided into Agilent Technologies and Keysight Technologies) and Tektronix sought to standardize instrumentation modules compatible with the VMEbus ecosystem. The bus was formalized through industry consortia including the VXIbus Consortium and influenced by committees within IEEE and VITA. Major milestones included adoption by military programs within DARPA projects and commercial test systems for firms such as Motorola, Intel, and Texas Instruments. Over time, compatibility work linked VXIbus with platforms like PXI and control frameworks used in laboratories at institutions such as MIT, Stanford University, and Caltech.

Technical Specifications

VXIbus specifies a 19-inch rack-mounted chassis with a backplane derived from VMEbus mechanics and signaling. The standard details slot pitch, power rails, cooling, and trigger/event lines to support instruments from vendors like Fluke, National Instruments, and R&S. It defines timing and synchronization features compatible with IEEE 1588 and allows integration with GPIB and RS-232 interfaces commonly used by Agilent Technologies and Tektronix instruments. Key electrical parameters include connector pinouts, signaling voltage levels, and thermal dissipation rates referenced by committees within IEC and IEEE.

Architecture and Modules

A VXIbus system comprises a chassis, controller (which may be a VXIbus-based processor or external PC), power modules, and instrumentation modules such as digitizers, function generators, and RF analyzers from manufacturers like Keysight Technologies, Rohde & Schwarz, Tektronix, LeCroy, and Anritsu. Modules follow mechanical classes and slot types to ensure interchangeability among suppliers such as National Instruments and Advantest. The architecture supports trigger lines, star triggers, and multi-chassis synchronization used in test setups by Lockheed Martin, Northrop Grumman, and Raytheon for complex system validation.

Software and Programming Interfaces

VXIbus devices are commonly programmed using instrument command sets like SCPI and accessed through APIs and drivers provided by vendors including National Instruments, Keysight Technologies, and Tektronix. Software frameworks such as LabVIEW, MATLAB, C/C++, and Python (with libraries maintained by communities at institutions like CERN and SLAC National Accelerator Laboratory) enable automated test sequences. Integration with middleware standards from IEEE and interoperability with PXI and GPIB controllers is supported through vendor drivers and VISA libraries from organizations such as VXIplug&play and the IVI Foundation.

Applications and Use Cases

VXIbus is used in automated test systems for semiconductor device testing by firms like Intel, AMD, and TSMC; avionics testing by Boeing and Airbus; and satellite payload validation at agencies such as NASA and the European Space Agency. Additional applications include telecommunications equipment certification by companies such as Ericsson and Nokia, radar system verification at BAE Systems and Thales Group, and research instrumentation at universities including MIT, Caltech, and Imperial College London.

Compatibility and Standards Compliance

VXIbus maintains compatibility with the VMEbus mechanical and electrical baseline while specifying additional instrumentation features standardized through the VXIbus Consortium and referenced by IEEE, VITA, and IEC committees. Interoperability with PXI, GPIB, and SCPI-controlled instruments is achieved via adapters and software drivers from vendors like National Instruments and Keysight Technologies. Certification and conformance testing are performed by test houses and consortium programs involving companies such as Tektronix, Rohde & Schwarz, and Agilent Technologies.

Category:Computer buses Category:Electronic test equipment