A broad range of programmable resistance decade boxes for applications requiring a programmable impedance unit, controlled manually and by a computer via an IEEE-488 or an RS-232 interface.

• Wide range and resolution: 1 mΩ to 100 MΩ
• Available at accuracies of : 0.01%, 0.02%, 0.05%, 0.1%, 0.5%, and 1%
• IET PRS20x_LabView Driver for IEEE-488.2 and RS-232 Versions
• effective programmable impedance unit controlled manually and by a computer
• Special RTD and custom configurations
• High power versions available
• Programmable "open circuit" and "short circuit" states optional
• Desktop and 19" Rackmount enclosures
• Dual / Combo rackmount models ( examples: dual resistance, resistance & capacitance )
• Windows tools and IEEE-488 interface software and hardware available
• Contact us for Custom or Built to Order Models

The PRS Series is a broad line of high programmable decade boxes. They provide direct resistance substitution as well as RTD (Resistance Temperature Detector) simulation, in a wide selection of ranges, tolerances and ratings.

The PRS programmable resistance decade box is a precision resistance source with excellent characteristics of stability, temperature coefficient, and power coefficient. High dynamic ranges are available, starting as low as 1 mW, and extending to as many as 10 decades. These features combined with a low virtually constant zero resistance make for very versatile instruments.

The PRS Series programmable resistance decade box features two optional special settings. An "open circuit" and a "short circuit". These modes are useful for obtaining reproducible transitions between settings, i.e. break-before-make or to short between settings. The "short circuit": setting also provides a reduced zero resistance.

Operation is both local using convenient direct-reading front panel thumbwheel switches, and remote with optional parallel RS-232, or IEEE-488 interfaces.
Both can provide an optional extra "10" position for each decade.

The PRS Series programmable resistance decade box employs very low resistance, low thermal emf relays with gold-clad silver-alloy contacts. A special design keeps contact resistance to a minimum. The gold plating keeps the silver contacts from becoming tarnished when unused, or when only low currents are passed through them. This is most often the case when only minute test currents are drawn by digital multimeters and other test instruments. Contact resistance remains low and repeatable.

The programmable decade box employees, high-quality gold-plated tellurium-copper five-way binding posts serve to minimize the thermal emf effects, which would produce errors in dc resistance measurements. All other conductors within the instrument, as well as the solder employed contain no metals or junctions that could contribute to thermal emf problems.

With a resolution as low as 1 mΩ and a maximum available resistance of over 100 MΩ, the PRS Series Series may be used for exacting precision measurement
applications requiring high accuracy, good stability, and low zero resistance. They are suited for automatic and manual calibration and testing, simulation of RTD'S, programmable loads, and many other laboratory and industrial applications. The PRS Series programmable resistance decade box may be rack mounted to serve as components in measurement and control systems.

PRTD Version: Low resistance versions with a fixed minimum resistance setting (4 Ω or specified by customer) are suitable for Programmable RTD (Resistance Temperature Detector) simulations. This design virtually eliminates the effect of zero resistance and relay contact resistance, providing the specified absolute accuracy over its entire range.