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Introducing the SmartResistor
an Automated Resistance Standard
US Pat. No. 6,798,214
Description:
The SmartResistor combines, into one transportable device, the three separate items needed to maintain resistance: a set of standard resistors, a controlled temperature bath and the measurement data defining those resistors.
Advantages of the SmartResistor:
To maintain and disseminate the ohm, a laboratory must have a set of resistance standards, usually at decade values (1W, 10W, 100W, etc.). The SmartResistor contains eight resistors. Seven decade values cover the range from 1W to 1MW. The eighth is user defined.
Traditional resistance standards are usually held in a constant temperature oil bath; these baths are bulky, noisy, and can not be transported. The SmartResistor contains a hermetically sealed enclosure held at a constant temperature, allowing portability. The control circuitry has sufficient power to overcome wide changes in ambient temperature.
The resistor housing provides immunity from changes in barometric pressure and relative humidity.
A resistance standard has no value without its characterization. This critical data includes a reference value in ohms, coefficients of temperature, power coefficient, frequency response and its drift over time. The SmartResistor's internal computer maintains all this data and displays it to the user. The data is available for integration into automated systems.
As time passes, the SmartResistor's calendar will apply drift corrections to the displayed value.
The SmartResistor contains an uncertainty calculator, freeing the metrologist from determining (and possibly mis-applying) the standard's combined uncertainty. The combined uncertainty will be displayed and updated automatically. As the state of measurement science advances, each uncertainty component can improve.
The SmartResistor's software generates and maintains control charts for each of its eight standards.
The SmartResistor's low-thermal eight channel scanner is by Data Proof. The scanner allows automated ratio buildups. Any of the eight resistance standards may be selected as R1 or R2 on the front panel.
A traditional resistance standard has only one reference resistance at a reference temperature. The SmartResistor allows the user to override the temperature setting of its internal constant temperature bath to increment or decrement resistance in extremely small steps. This feature allows the evaluation of a measurement system's resolution.
Cost Savings of the SmartResistor:
A single SmartResistor is designed to replace eight resistance standards, a constant temperature oil bath, a scanner, a temperature datalogger and associated software at a significantly lower cost.
Automating the Resistance Lab:
The SmartResistor is designed with simple, intuitive operator controls. All functions and controls can be integrated into an automated system via the SmartResistor's interfaces. The standard interfaces supplied will include ethernet and IEEE ports.
Protecting Resistance Standards:
Traditional resistance standards can be permanently damaged by exposure to temperature extremes. The SmartResistor contains a battery-powered temperature datalogger, constantly monitoring its internal temperature. Even in storage, the logger will sample and store temperatures hourly for a period of approximately two years. On power-up, the SmartResistor reviews this temperature history and warn the operator if any extremes have been suffered.
Each SmartResistor is supplied with a rugged transport container.
Future Developments:
The SmartResistor Model SR covers the range from 1W to 1MW. A SmartShunt, Model SS, is planned for use as a low resistance standard, containing five decade values from from 1W to 0.000 1W. It may be used for the highest accuracy current measurement, up to 100 amps. A high resistance standard, Model SH, is planned for resistance between 1MW to 1TW. Extended models are planned, including a high current shunt, and automated Hamon Transfer Standards.
Longevity:
The SmartResistor is designed for extended use. Care has been exercised to select the most reliable and rugged components. The software runs on Microsoft Windows XP. Software upgrades will be provided at no cost to customers as they become available. The SmartResistor is internet compatible, so that evaluation, uploads and diagnostics can be performed anywhere in the world.
The SmartResistor carries a five year parts and labor warrantee.
Test Results:
Please periodically return to this website for test results on our prototypes.
Related Information:
For additional information on Ohm-Labs, Inc. please visit www.Ohm-Labs.com. Thank you for your interest in the SmartResistor. We welcome any comments or suggestions you may have. Please contact us with any questions you may have concerning resistance standards.
Click here for information on Ohm-Labs' history with resistors.
Click here for a helpful article about the use and maintenance of resistance standards.
Click here to see information about our line of traditional resistance standards.