Features and Benefits

Since its inception in 1987, MI has been providing customers with the best in resistance measuring equipment. As the original manufacturer of the Automated Direct Current Comparator (DCC) Resistance Bridge, MI has been the industry leader in providing the highest level of automated resistance bridges and turnkey systems to metrology laboratories worldwide.

The AccuBridge® 6242D (furthermore 6242D) is ideal for measurements in both resistance metrology and temperature thermometer applications. With its innovative technology, the 6242D’s speed, measurement accuracy, and data handling capabilities make it the preferred primary resistance measurement system in primary and calibration labs worldwide. The 6242D is designed for flexibility and ease of use.

Ratio Range & Accuracy

The 6242D DCC with its binary wound current comparator technology balances current ratio with an effective resolution of 25-bit. It provides ratio measurements with an accuracy to better than 100 ppb with a  linearity of better than 5 ppb. The 6242D can perform ratio measurements (Rx/Rs) with resistances valued from 0.001 Ω to 1 GΩ range. A line of optional high current range extenders permits measurements down to 1 μΩ for shunt resistance or direct-current current transformer (DCCT) measurement applications.

Automated Resistance Operation

The 6242D Bridge itself can ratio a standard resistor with another resistor being tested. Optional 10-, 16- or 20-channel scanners can be used individually or together to connect to up to 40-channels of ratio measurement for up to 40 different test resistors.

The 6242D is perfectly suited for front panel operation, or you can team it with MI’s 6242D-SW Windows®-based operating software for fully automated measurements, history logging, graphing, and regression analysis. Front panel operation with the 6242D’s touch sensitive display panel provides full bridge capabilities to the operator. The ratio or direct resistance measurements can be made. Multiple measurements over time can be numerically displayed or graphically displayed to best fit your needs.

The AccuBridge® Family of Bridges

The 6242D is a high-performance model MI Bridge. It is one of a family of bridges where there are various bridges optimized for different tasks from measuring Quantum Hall Resistance Standards (QHR) over a smaller range of resistance but with excellent uncertainties, to others which are a better fit for other labs with a broader range of measurements but with larger uncertainties. Three different bridge designs use different measurement methods to measure over 21 orders of magnitude of resistance, from 1 μΩ to 10 PΩ. The Accubridge® family offers the best line of bridges available for measuring the widest range of resistance.

Overview

The 6242D measures both ratio and absolute values. You select functions using the menu on the 6242D’s large touch screen display. For absolute measurements, you enter the value and related uncertainty of the standard resistor using the display’s keypad. You enter the measurement functions such as current through the unknown resistor, settle time, number of measurements, and number of statistics the same way.

The 6242D’s low-noise, touch screen display is interactive with the measurements, as shown in the screen images below. When a reading is complete, the average value and uncertainty (based on the number for statistics) are displayed. All uncertainty calculations are 2 sigma level.

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The Summary tab displays current measurement data

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The Table tab displays a chronological list of measurement data

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The Graph tab displays a graphical representation of the data

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The Measurement Information tab displays measurement parameters

Measurements International provides world-class expertise in DC resistance metrology to National Measurement Institutes (NMIs) primary, and calibration laboratories who need to achieve the lowest possible traceable uncertainty in their measurements and calibration equipment. As your accreditation and global support partner, MI helps ensure your competitive advantage by offering leading product knowledge and applications expertise through coaching, system design, implementation, calibration services, and ongoing expert support.

At MI, it’s not only about the equipment and science; it’s about what you can do and the ease with which you can do it.

Automatic current reversal ensures that DC offsets and thermals are cancelled out during the measurement. The 6242D has a standard (Rs) input and an unknown (Rx) input for measuring the ratio of the two resistors. All resistor connections are made using 4-terminal connections. Calibration verification can be made by performing an interchange measurement at any ratio. The interchange technique works at all ratios.