• IEEE1588 – A solution for synchronization of networked data acquisition systems?

      Corry, Diarmuid; ACRA CONTROL INC (International Foundation for Telemetering, 2006-10)
      One of the problems for manufacturers and users of flight test data acquisition equipment, is to guarantee synchronization between multiple units acquiring data on the vehicle. Past solutions have involved proprietary interconnects and multiple wire installations increasing weight and complexity and reducing inter-operation of units. This problem has become particularly important given the trend towards commercial busses, especially Ethernet, as a system interconnect. The IEEE1588 standard offers a way to transmitting time accurately over Ethernet. This paper discusses the standard, how it might be implemented, and examines the issues involved in adopting this standard for flight test data acquisition. A particular implementation that results in a synchronized four-wire Ethernet based distributed data acquisition system is discussed in section 3.
    • XidML – Two Years On

      Corry, Diarmuid; Acra Control Inc. (International Foundation for Telemetering, 2006-10)
      In 2004 ACRA CONTROL introduced XidML as a published standard for instrumentation definition via XML. After two years in the field, much feedback and two revisions, this paper outlines where the standard is now, some of the lessons learned and discusses some ideas for where next. XidML allows any package, message or frame to be defined including PCM, MIL-STD- 1553, Ethernet and storage formats, it is also used to define the settings for instrumentation as diverse as Analog to Digital modules, MIL-STD-1553 monitors, PCM encoders, recorders, bit-syncs, and decoms. Importantly it facilitates the EU range and data format to be defined for large parameter lists. The key elements in the standard are discussed along with some lessons learned.