Test and measurement markets are increasingly demanding hybrid instruments that satisfy both general-purpose and dedicated applications.
By Mark Cejer
EDITED BY JOHN R. GYORKI
A single piece of electronic equipment usually can't satisfy all test, data-collection, and analysis requirements for new products on the manufacturing floor or for complex research and development labs. Integrating many pieces of dedicated equipment to accomplish one job increases the out-of-box hardware and software costs as well as the less obvious integration, installation, and start-up costs.
Some of these costs crop up again when the one-track system must be modified for a different job. The time to debug the pieces and develop test programs often cost more than the hardware. Therefore, it pays to look at a hybrid instrument that incorporates multiple functions. It should come in a small box, with simple, intuitive start-up software, and program libraries and drivers compatible with Microsoft and ActiveX environments. These factors are crucial for holding down total system cost. The one hybrid can have a per-unit price and start-up cost lower than the collective costs of the individual units.
The best hybrid measuring instruments can do today's job and adapt easily to largely unknown future requirements. These requirements usually include a wide range of measured variables and their amplitudes, resolution, and sensitivity. Requirements are also likely to include NIST-traceable accuracy, number of channels, and scan rates.
Hybrid systems do the work of several general-purpose or specialized measurement systems that analyze, scale, and record a particular set of physical, chemical, or electrical variables. Hybrids replace traditional benchtop instruments, data loggers, chart recorders, or PC-controlled GPIB instruments and plug-in cards with data-logger front ends. However, hybrid instruments normally contain their own embedded microcomputer chips with optional I/O for PCs. Having such computer power behind the measurement hardware increases data-acquisition speed, accuracy, and the amount of collected data. The measurements are particularly necessary during production to test multiple-measurement devices, switching systems, and mixed-signal systems.
Because test-system developers are likely to become involved with several types of applications, ideal hybrid instruments combine features found in the most common test equipment. One hybrid, for example, combines source and measurement functions in the same instrument for tight integration of stimulus and response testing, while another combines data acquisition and USB communications in a single module as key elements for a measurement network.
The hardware and software set residing in a single hybrid instrument is a major advantage. It can reuse large chunks of application software on new projects. This is particularly useful when a Microsoft environment is used with portable ActiveX controls and drivers that support a variety of programming languages and test development packages.