Data acquisition (DAQ) systems certainly existed before 1985, but EE’s in-depth coverage began with publication of that year’s September issue. As stated in the “How to Automate Almost Anything” article, “[1985] systems represent a marriage of the standard industrial datalogger to more modern computer technology….”
Courtesy of National Instruments
Companies listed included Elexor Associates (same phone number today but called StarTrak, “tracking, monitoring, and controlling refrigerated trucks”); Dynage Controls (dissolved 2010); MetraByte (bought by Keithley Instruments 1987); and Solartron Instruments (Schlumberger Instruments prior to 1993, part of AMETEK since 2005). John Fluke, Hewlett-Packard, and Racal Dana also addressed the DAQ market.
In the September 1986 story, “Data, More Data,” MetraByte’s Bob Judd commented, “I believe that the market today is very small compared to what it will be in a few years.” How right he was!
A couple of very important factors came together in the mid-1980s: First, the PC provided an inexpensive standard platform, which encouraged development of the personal computing software/hardware infrastructure that we take for granted today. The second big thing was the founding of the VXI Consortium in 1987 by companies including HP (now Agilent Technologies), Tektronix, Racal Instruments (now EADS North America Defense Test and Services), Colorado Data Systems, and Wavetek (now Fluke). Today, Fluke, Tektronix, and Keithley are part of Danaher.
In a July 1988 article, National Instruments’ Ron Wolfe discussed the new VXI standard, using NI’s GPIB-VXI interface module as an example. He referred to pre-VXI modular instrumentation systems such as CAMAC but concluded that limited software tools relegated CAMAC to high-end applications. In Wolfe’s view, NI’s LabVIEW graphical programming language in conjunction with VXI “ensures ease of use while allowing for construction of… complex and high-performance systems.”
By 1990, EE was running six VXI-related articles per year—up to 13 and a separate buyers guide in 1993. As VXI was addressing applications for MIL/Aero and large industrial users, PC-based DAQ continued to gain popularity. A Burr-Brown February 1992 article on DAQ board selection presented advantages as well as pitfalls of using these attractive, low-cost solutions. In the same issue, RadiSys made the case for VXI systems using embedded PCs, claiming that more than 50 million PCs were in use.
The Peripheral Component Interconnect Special Interest Group (now PCI-SIG) was formed in 1992. The fast PCI bus soon displaced the older ISA standard and formed the foundation for the PXI specification released in 1997, managed by the PXI Systems Alliance (PXISA). Much as VXI had added special test-oriented signals to the existing VSA bus, PXI enhanced PCI.
EE ran at least seven DAQ articles in each of the years from 1995 through 2000. The range of topics was broad, including several signal-conditioning stories such as “A Primer on Signal-Conditioning Issues” published in November 1996. Test-system architecture was a recurring theme, given several viable platforms to choose among. The September 1998 National Instruments article “What Bus Architecture Is Right for You?” and the March 2001 Bustec story “What Is the Ideal Bus?” addressed this subject.
The 2005 release of the PXI Express (PXIe) standard retained software compatibility with PXI but transferred data serially at 2 Gb/s in both directions. As PXI and PXIe were being adopted, the universal serial bus (USB) also attracted followers. USB 1.0 was released September 1996 for keyboard and mouse interfacing and ran at 1.5 or 12 Mb/s. Version 2.0 in April 2000 increased speed to 480 Mb/s, and today’s USB 3.0 achieves 5 Gb/s. The January 2009 Tektronix article “USB 3.0 Physical Layer Measurements” highlighted the need for compliance testing because of the high rate and relatively uncontrolled channel characteristics.
Ethernet, yet another technology, was well established within LANs and, since 2005, associated with LXI. To support the new standard, EE published LXI ConneXion, a separate magazine dedicated to the LXI standard and related test applications.
The introduction of the IEEE 1588 Precision Timing Protocol in 2008 was a game changer because it provided nanosecond-synchronism for geographically large systems. Symmetricon covered this topic in the January 2010 story “Improving Synchronization With 1588 Transparent Clocks.”
Wireless sensors are the most recent opportunity available to test system developers. Implementations range from redundant self-routing networks to solutions with a single sensor.