Instrument certification as part of a modular test platform architecture

The use of modular test systems for depot, intermediate, and factory test applications has increased dramatically in the last two decades. Starting with the VME Extensions for Instrumentation (VXI) architecture in the early 1990's, card modular architectures have become an integral part of today's Automatic Test Systems (ATS) for military -aerospace components and systems. Today, the primary card modular architecture is based on the PCI Extensions for Instrumentation (PXI) standard with thousands of PXI-based systems in use today and with next generation ATS platforms for military programs transitioning to PXI as well. The flexibility and configurability associated with today's modular architectures has also created new challenges for the calibration and certification of these systems. Historically, the process for re-certification of modular instruments has been to remove and return the modules to the original equipment manufacturer (OEM) or a 3rd party test house, resulting in system down time. However, a better certification method for a card modular architecture is to develop an overall methodology and implementation that allows recertification of modules within the host system, including the possibility to extend this process to include recertification of "box" instruments as well. This paper discusses the features and benefits of a PXI-based standards module which provides the basis for implementing a system level certification strategy. By employing only one standards module in the system, recertification logistics and maintenance can be simplified, resulting in extended system up time and offering test managers added flexibility for supporting in-house certification of modular test system components. By incorporating frequency, resistance and voltage standards and source / measurement facilities, a certification strategy can be developed for an ATS platform that is based on specific test application accuracy requirements.