Catalog excerpts


Sensors Transducers Transmitters Instruments

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Mandala (sanskrit: circle) The becoming and being of life and universe was archetypically illustrated with concentrical circles as in Mandalas or Gothic-church-windows with a focus representing each culture's ori-gine: God, Buddha or nous in old Greece. Meditation should lead mankind through all the circles closer to the focus. Science explains the creation of life along these lines. Out of a nucleus, a monad, life started. Always in danger to be destroyed, sensory cells evolved to recognize the danger. New forms of life evolved to evade the danger. Millions of cycles later, sensory cells...

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On the Trail of Swiss Watchmakers High precision mechanics has a long tradition in Switzerland, renowned mainly for the mechanical Swiss watches. These handmade masterpieces find a growing clientele who see in this item – as the marketing approach successfully infuses – a friend they can rely on when achieving extraordinary accomplishments as sportsmen, pioneers, scientists or as a 007-hero. What is the secret? Does material have a soul striving for perfection as many philosophers have postulated? Is the watchmaker conveying his soul through many hours of manufacturing into this piece of...

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Galileo Galilei, born in Pisa (Italy), obtains the patent for a machine to pump water from a river for the irrigation of land. The heart of the pump was a syringe. Galileo Galilei found that 10 meters was the limit to which the water would rise in the suction pump, but had no explanation for this phenomenon. Scientists were then devoted to find the cause for this. Evangelista Torricelli (Torr), Italian physicist, filled a tube 1 meter long, hermetically closed at one end, with mercury and set it vertically with the open end in a basin of mercury. The column of mercury invariably fell to...

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History of Pressure Measurement Mechanical Measurement Technologies Lucien Vidie, French scientist, invented and built the aneroid barometer, which uses a spring balance instead of a liquid to measure atmospheric pressure. The spring extension Aneroid Barometer under pressure is mechanically amplified on an indicator system. Employing the indicator method of Vidie, Eugène Bourdon (founder of the Bourdon Sedeme Company) patented 1849 the Bourdon tube pressure gauge for higher pressures. Electrical Measurement Technologies The first pressure transducers were transduction mechanisms where the...

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Up to the 1970’s, there were Basic Specifications (OEM’s) only transducer manufacturers. 0,1...1500 bar nom. 1 mA/constant current nom. 150 mV/mA > 1 bar nom. 200 mV/mA/bar < 1 bar typ. 0,25 %FS / max. 0,5 %FS (best straight line through Zero) < 0,1 mV/K (-10.80 °C) < 0,02 %/K (-10.80 °C) depending on range and design 0,002 %FS best * 0,02 %FS standard abs. * 0,05 %FS standard rel. * Ranges In 1977, KELLER introduced the Excitation first OEM modules, the Series 10 Signcil Oulpul' for lower pressures with 0 19 mm, the Series 8 for higher pressures Un^nly with 0 15 mm, today a...

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The error band as a specification describes the maximum deviation in accuracy from the tar- get value of a transmitter of any point in the specified pressure and temperature range. Over the temperature range, the accuracy is a combination of Linearity, TC Zero and TC Gain. The error band can be found if the measured data of the sensor or transmitter are drawn up in constant pressure lines over temperature (Graph 1) or constant temperature lines over Error Band (-10…80 °C): Error Band (-10…50 °C): pressure (Graph 2). In both graphs, the trans- mitter has been adjusted for highest accuracy at...

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Today, the KELLER modular system contains many OEM sensor elements starting from only 0 9,5 mm, suitable for mounting or welding. The most common are listed below. KELLER has developed various important technologies to amplify and compensate the signal from the OEM sensor. Examples of the available circuit boards can be seen on the following pages. All 500 KELLER standard transmitters are just a combination of one of these sensor elements and the appropriate circuit board. A small selection of transmitters are presented on the next pages. 1 Fully brazed, no O-rings 2 Base pressure

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Conventional Amplifiers For highest adjustment accuracy, Zero and Gain are optimally set by potentiometer at room temperature. Accuracy is defined by the linearity error. Board: 0 16,8 mm. Output: 0...10 V, 4...20 mA, 0,5...4,5 V. All available ranges in absolute or gauge version. Industrial Amplifiers (ProgRes) The industry requires reliable measurements within a certain temperature range. The error band describes the maximum deviation at any pressure within the compensated temperature range. Accuracy at room temperature is normally not of interest. ProgRes is an amplifier with 4...

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The ProgRes ASIC for 0,5...4,5 V output is integrated within the oil filled sensor housing, whereby the programmable amplifier-ASIC is mounted and contacted beside the actual absolute pressure measuring element on the same glass-feed-through. Only one pin is needed for the programming of the finished sensor. Output: 0,5...4,5 V. Absolute versions > 5 bar. Highest reliability at lowest cost is of priority for applications in the automotive field. A large temperature range from -40.135 °C and a high level EMC-protection is required. Adjustment and compensation either by fixed or laser trimmed...

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µP-based Signal Conditioners The graphs in the error band description can be used to considerably improve the accuracy of certain measurements. For instance, a measurement is 2,5% Subtracting 1 % from the measu- Digital Compensation with µP’s create a coherent map of the deviations from the target value from a set of measurements at Error band verified by DKD 08101 Deviation [%FS] defined pressures and temperatures. This map is defined by a set of coefficients. the exact pressure value to a set signals. By this method, called mathematical modelling, the error band is typically narrowed down...

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All KELLER catalogs and technical brochures

  1. ECO2

    5 Pages

  2. ARC-1

    7 Pages

  3. Series 26 Y

    2 Pages

  4. Series 26 W

    1 Pages

  5. Handpump K/P

    1 Pages

  6. K-114 BT

    3 Pages

  7. K-114

    3 Pages

  8. 21 ge

    1 Pages

  9. LEO 3

    1 Pages

  10. FA-23

    1 Pages

  11. Series 8

    2 Pages

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