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Trends in Temperature Calibration. David Southworth VP: Sales and Marketing Isothermal Technology Ltd, UK (Isotech) www.isotech.co.uk. Trends in Temperature Calibration. We see from Industry to Primary Metrology a demand for greater accuracy A demand for more confidence

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Trends in temperature calibration
Trends in Temperature Calibration

David Southworth

VP: Sales and Marketing

Isothermal Technology Ltd, UK (Isotech)

www.isotech.co.uk


Trends in temperature calibration1
Trends in Temperature Calibration

  • We see from Industry to Primary Metrology a demand for greater accuracy

  • A demand for more confidence

  • We have responded with innovative new technology


Introducing isotech
Introducing Isotech

  • David Southworth

  • Worked at Isotech since 1984

    • Engineering Background

    • VP Sales and Marketing since 2006


UK Company

  • Isotech

    • Established in 1980

    • Premier Supplier of Temperature Equipment

    • Premier UKAS Temperature Calibration Lab

    • Premier Source of Articles and Training


NTPL

  • NTPL – Isothermal Technology's Calibration Laboratory


NTPL

  • NTPL – Isothermal Technology's Calibration Laboratory

    • Best Measurement Capability, Gallium Fixed Point Cells

      • 0.000,07°C!

    • Within 4uK of NIST Reference Cell – 0.000004°C

    • +/-0.07mK 2 Sigma Uncertainty (NIST only National Lab with smaller uncertainties


National metrology institutes use isotech equipment
National Metrology Institutes use Isotech equipment

  • Primary Standards

    • ITS-90 Fixed Points

    • Standard Thermometers

    • Associated Equipment

Many Nations rely on Isotech for their Primary Temperature Standards


Secondary and industrial
Secondary and Industrial

  • Secondary Calibration Equipment

    • Liquid Baths

    • Fluidized Furnace

    • High Temperature Furnaces

    • Thermometers

    • Instruments

  • Industrial Calibration Equipment

    • Dry Blocks

    • Liquid Baths

    • Probes, Indicators and Software


Introducing isotech1
Introducing Isotech

  • Operated a Calibration Lab Since 1983

  • Achieved Accreditation in 1985

  • We regularly provide training courses


Introducing isotech2
Introducing Isotech

  • Manufacture Calibration Equipment

    • Industrial, Scientific and Primary Laboratories

  • We Use What We Produce

    • Isotech Lab equipped with Isotech products


Introducing isotech3
Introducing Isotech

  • NTPL equipped with Isotech Products

    • Industrial, Scientific and Primary Laboratories

  • UKAS Accreditation

    • Performance Claims Validated with regular audits


Trends in temperature calibration2
Trends in Temperature Calibration

  • Always a demand for greater accuracy

    • NEVER less accuracy – always better


Trends in temperature calibration3
Trends in Temperature Calibration

  • We see a demand to improve the accuracy of calibrating industrial sensors

  • For example Green Buildings

    • Calibrating Thermistors more accurately can save enormous amounts of money and protect the environment


Trends in temperature calibration4
Trends in Temperature Calibration

  • Isotech Response

    • Greater Accuracy with innovative fixed Point Solutions

      • ISOTower

    • Measuring Systems

      • milliK


Introduction

Most calibrations are performed by comparing the unknown characteristics of the thermometer under test to a calibrated reference thermometer

But how are the reference thermometers calibrated?

Introduction


Introduction1

The answer is, in a series of known and fixed temperatures where pure substances (usually metals) melt or freeze

Introduction


Introduction2

Three things are required before a thermometer can be calibrated at a fixed point

A fixed point cell (an ingot of pure metal inside a specially shaped graphite crucible)

An apparatus or furnace to melt and freeze the ingot of metal uniformly

The thermometer must be sufficiently immersed so that the sensing element is at the cell’s temperature

Introduction


Introduction3

Fixed point systems to National Laboratory standards are very expensive and are also inconvenient if the thermometer is short. So shorter and smaller fixed point systems were developed

The shorter, smaller and cheaper fixed points are approximations to those in National Laboratories and they seldom provide sufficient immersion for the thermometer being calibrated

Introduction


Introduction4

To offer the customer small uncertainties the smaller cells are calibrated in large furnaces and the user must make allowance for the stem conductance of his thermometer

This is not very satisfactory

Introduction


A new approach

What if are calibrated in large furnaces and the user must make allowance for the stem conductance of his thermometer we throw the existing ideas out of the window and start again?

What if the cell and furnace become one and inseparable?

What if the immersion necessary is calculated and compensated?

Might we end up with a novel but improved solution to fixed point calibration?

A New Approach


New design patents applied for

The key to the new design is a heat siphon in the shape of a Dewar with elongated inner tube

The key feature of the Siphonic Dewar is that it is gradient-free so a cell inside will melt and freeze uniformly

Next the cell fits snugly inside and is sealed in place surrounded by 1 atmosphere of pure argon

New Design (Patents Applied For)


Combining cell and apparatus

The concept was patented and called a Siphonic Cell (S.C.) Dewar with elongated inner tube

Combining Cell and Apparatus


Combining cell and apparatus1

The ideal apparatus to surround a cell is a heat pipe or heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

Combining Cell and Apparatus


How does it work
How Does it Work? heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

  • Two heaters are used, the main heater for the Siphonic Dewar, the second heats the immersion compensator to the same temperature as the cell


Immersion compensator ic
Immersion Compensator IC heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

  • The depth from metal surface to the bottom of the re-entrant tube is 180mm and this is inadequate for most SPRTs

  • The unit under test therefore needs to go through an isothermal zone above the cell set to the cell’s transition temperature


Immersion compensator ic1
Immersion Compensator IC heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

  • The Immersion Compensator actively provides the Isothermal Zone


How does it work1
How Does it Work? heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

  • The control temperature is set above the melt temperature – the cell melts. 0.1°C above yields a 30 hours melt. 0.2°C above 15 hours melt etc

  • Setting the temperature 0.1°C below yields a 30 hour freeze etc


Results
Results heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

  • A series of melt and freeze plateau graphs follow

Slide: 28


Siphonic sn fixed point cell melt plateau
Siphonic Sn Fixed Point Cell Melt Plateau heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result


Siphonic sn fixed point cell freeze plateau
Siphonic Sn Fixed Point Cell Freeze Plateau heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result


Siphonic zn fixed point cell melt plateau
Siphonic Zn Fixed Point Cell Melt Plateau heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result


Siphonic zn fixed point cell freeze plateau
Siphonic Zn Fixed Point Cell Freeze Plateau heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result


Siphonic al fixed point cell melt plateau
Siphonic Al Fixed Point Cell Melt Plateau heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result


Siphonic al fixed point cell freeze plateau
Siphonic Al Fixed Point Cell Freeze Plateau heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result


German laboratory invested in isotowers
German Laboratory Invested in ISOTowers heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

  • KK set up a laboratory based on ISOTowers


Isotowers in germany
ISOTowers in Germany heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

  • Achieved Daaks (formerly DKD accreditation

  • Tin 3mK

  • Zinc 3mK

  • Aluminium 5mK


Trends in temperature calibration5
Trends in Temperature Calibration heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

  • Always a demand for greater accuracy

    • As well as ISOTowers we have responded with new instrumentation


Trends in temperature calibration6
Trends in Temperature Calibration heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

  • Isotech Response for Higher Accuracy

    • Measuring Systems

      • milliK


Millik
milliK heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

  • High Accuracy Precision Thermometer

  • Why called milliK?

    • One thousandth of a ⁰C, 0.001 ⁰C is 1milli Kelvin, mK

    • milliK works to this level


Millik greater accuracy
milliK: Greater Accuracy heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

  • Resistance thermometers

    • 3mK at 0⁰C

      • 4mK over 1 year

    • Resolution of 0.0001⁰C, 0.1mK

  • Thermocouples

    • 2µV and 4µV over 12 months

      • For Type K – 4µV =0.1 ⁰C


Millik logging
milliK Logging heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

  • Other instruments can store up to several thousands of data points

  • The milliK has capacity to log time stamped data for up to six months internally, add a low cost USB Memory Drive and store a lifetime of data


Millik usb
milliK USB heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

  • On the same USB you can plug a Mouse / Keyboard to ease entering probe calibration data, Set Programs etc.


Millik innovation
milliK Innovation heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

  • Colour Display

    • Choice of Strip Chart or Numeric

      • Includes simultaneous view of all three channels


Millik innovation1
milliK heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would resultInnovation

  • Isolated Inputs

    • High Degree of Galvanic Isolation

      • Sensor Inputs Isolated from current input

      • Avoid Problems with high voltage pick up on TC inputs

    • Safety


Millik innovation2
milliK heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would resultInnovation

  • Built in 24VDC PSU

    • Isolated

    • Power Transmitters


Millik innovation3
milliK heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would resultInnovation

  • Connectivity

    • Two Serial Ports

      • For PC connections to PC and Dry Block

      • Easy to program SCPI Style Interface

    • Controls ISOTECH Dry Blocks and Baths


Millik innovation4
milliK heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would resultInnovation

  • USB Host

    • Memory Stick / Mouse / Keyboard

  • Ethernet

    • Remote control over network


Expandable
Expandable heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

The millisKanner allows for more channels


Expanding the millik
Expanding the milliK heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

  • The millisKanner Channel Expander

    • Connect SPRT, PRT, Thermistor or Thermocouple on any channel

  • It is not just a scanner


So what is the milliskanner
So what is the millisKanner? heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

  • Expands milliK to have more inputs

  • Allows for an SPRT, PRT, Thermistor or Thermocouple on any channel


So what is the milliskanner1
So what is the millisKanner? heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

  • Flexibility of Inputs

    • No need for lots of expensive modules


So what is the milliskanner2
So what is the millisKanner? heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

  • Solid State Design

    • No mechanical relays

    • High Reliability

  • Isolated Inputs

    • Galvanic Isolation Between both contacts and PSU and Control Circuitry

    • Benefits – Better Measurements and lower noise


So what is the milliskanner3
So what is the millisKanner? heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

  • Intelligent Design

    • Automatically adapts to suit sensor type

      • Handles Thermal EMFs for PRT and TCs

  • milliK Automatically Senses new millisKanners

  • All Driven from milliK

  • milliK does the thinking

    • Self configures – no wrong cables


  • So what is the milliskanner4
    So what is the millisKanner? heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

    • milliK supports maximum of four millisKanners

    • 33 Channels

      • Plus Current Input


    New solution millik
    New Solution: milliK heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

    • We have a new solution for multiple channel precision measurement

    • Unmatched


    Trends in metrology
    Trends in Metrology heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

    • NEW SI

    • Interest in redefining the kilogram, the ampere, the kelvin and the mole


    Trends
    Trends heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

    • Proposed new definition for the Kelvin

    • The Kelvin is currently defined as the fraction 1⁄273.16 of the thermodynamic temperature of the triple point of water (exactly 0.01 °C)


    Trends1
    Trends heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

    • Rather than have an “artefact” (WTP Cell) goal is to relate the Kelvin terms of the SI unit of energy, the joule by fixing the value of the Boltzmann constant k

      • which is simply the proportionality constant between temperature and thermal energy kT


    Trends2
    Trends heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

    • A proposed new definition (definition is still being debated)

      • The kelvin is the change of thermodynamic temperature T that results in a change of the thermal energy kT by exactly 1.380 65X X × 10-23 joule, where k is the Boltzmann constant

    • Problem is the Boltzmann Constant is not known to a sufficient level

    • Number of experiments on going to determine the exact numerical value


    Trends3
    Trends heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

    • For almost all users, the redefinition will pass unnoticed; thermometers calibrated before the change will continue to indicate the correct temperature

    • Water Triple Point Cells will still be used to calibrate SPRTs


    What is a water triple point cell
    What is a Water Triple Point Cell? heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

    • Most Important Defining Fixed Point

      • All three phases coexisting in thermal equilibrium

        • Solid (Ice)

        • Liquid

        • Vapour

    • Unique

      • only realizable defining fixed point common to the Kelvin Thermodynamic Temperature Scale (KTTS) and the ITS-90

    0.01°C

    (273.16 K )


    Water triple point cells
    Water Triple Point Cells heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

    • Lots of Different Sizes


    Water triple point cells1
    Water Triple Point Cells heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

    • A Super Cooled Cell


    Trends in temperature calibration7
    Trends in Temperature Calibration heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

    • For Primary Standards we see not a new definition but to better understand the fixed points

    • We see a demand to improve ITS-90 Fixed Point Cells and better understand the effects of impurities


    What is an its 90 cell
    What is an ITS-90 Cell? heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

    • ITS-90 Fixed Points

    A Sealed Fixed Point Cell


    Standard its 90 cells
    Standard ITS-90 Cells heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result


    Its 90 fixed points
    ITS-90 Fixed Points heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result


    Trends in temperature calibration8
    Trends in Temperature Calibration heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

    • We see a demand to for increased confidence in measurements made with thermometry bridges


    Innovative new bridges microk
    Innovative New Bridges: microK heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result


    Innovative new bridges microk1
    Innovative New Bridges: microK heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

    • A Thermometry Bridge that can work to 17µK at Wtp (0.000017ºC)

    • As well as SPRTs works with all laboratory standard types

      • PRTs, Thermocouples and Thermistors


    Resistance and voltage
    Resistance AND Voltage heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

    • microK supports

      • SPRTs and IPRTs

      • Thermistors

      • Thermocouples

        • Only instrument in its class to do this

        • A DVM with comparable performance has a similar cost to the microK alone


    The a to d
    The A to D heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

    • Uses specially designed analogue to digital converter used in conjunction with a digital signal processor (DSP)

    • Uses a unique adaptation of existing advanced sigma-delta ADC techniques to achieve linearity better than 0.07 ppm.

    • A further major benefit of this ADC technique is its low noise performance,

      • reduced by a factor of 32 over conventional sigma-delta ADC circuits

    • Licensed from NPL


    Zero drift for resistance
    Zero Drift for Resistance heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

    • The microK uses a “substitution technique” in which the Device-Under-Test and the Reference are successively switched

      • This means that the stability of resistance ratio measurements is immeasurably small

    • Unique – Drift Free in Ratio Measurement


    Three channel
    Three Channel heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

    • Three Input Channels

      • Best Practise Ready

      • Allows two standards and a device under test to be connected simultaneously

    • Expandable

      • Add up to 90 channels


    Easy to use
    Easy to Use heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

    • Operated by large touch screen display

      • Intuitive

      • Can add keyboard and mouse


    Easy to use1
    Easy to Use heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

    • Includes Graphing Facility

      • Auto or Manual Scales

      • Intuitive


    Easy to use2
    Easy to Use heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

    • Log Data to Internal Memory

    • Or USB Pen Drive


    Solid state reliable
    Solid State - Reliable heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

    • All Solid Sate

    • Reliable

      • No potentiometers

      • No Dials

      • No Knobs

      • No Relays


    Microk
    microK heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result


    New innovation for thermometry
    New Innovation for Thermometry heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

    • Isotech microK


    Demand for higher accuracy
    Demand for Higher Accuracy heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

    • How can you trust a microK?

    • How can you trust an AC Bridge?

    • How can you trust a high accuracy thermometer?


    Ratio measurement
    Ratio Measurement heat siphon. If the outer wall of a metal clad fixed point cell also becomes the inner wall of the heat siphon then a very simple structure of ideal thermal profile would result

    • Bridges of this type make ratio measurements


    Trends in temperature calibration increasing bridge confidence
    Trends in Temperature Calibration: Increasing Bridge Confidence

    • One simple method for checking a resistance bridge is to measure a pair of resistors separately, and then measure the two in series

    • Ideally the series measurement should equal the sum of the two individual measurements


    Trends in temperature calibration increasing bridge confidence1
    Trends in Temperature Calibration: Increasing Bridge Confidence

    • Another check is to measure the ratio of two resistances, then swap the resistors and measure the reciprocal ratio (or complement)

    • Ideally the product of the two measurements should equal 1.0 exactly

    • Problem is how to check over the whole range?


    Trends in temperature calibration increasing bridge confidence2
    Trends in Temperature Calibration: Increasing Bridge Confidence

    • The answer is to use the RBC

    • The RBC exploits the same principles as the linearity and complement check

    • It uses a network of four stable four-terminal resistors that can be connected in 35 different series and parallel combinations

    • The combinatorial calibration method is particularly powerful because it is not necessary to know the actual values of the four resistors


    Trends in temperature calibration increasing bridge confidence3
    Trends in Temperature Calibration: Increasing Bridge Confidence

    • Concept developed by Rod White – at the NMI of New Zealand

    • Now an Automatic Version

    • Includes Software to create the report


    Trends in temperature calibration increasing bridge confidence4
    Trends in Temperature Calibration: Increasing Bridge Confidence

    • “A Method for Calibrating Resistance Thermometry Bridges” Rod White evaluated 38 Bridges, small but significant faults were found with 15% of those tested, but “like the walking wounded” they continued to provide a plausible reading.


    Trends in temperature calibration increasing bridge confidence5
    Trends in Temperature Calibration: Increasing Bridge Confidence

    • “A Method for Calibrating Resistance Thermometry Bridges” Rod White evaluated 38 Bridges, small but significant faults were found with 15% of those tested, but “like the walking wounded” they continued to provide a plausible reading.



    New automatic version1
    New Automatic Version Confidence

    • Same Size as a Standard Resistor

      • Can be immersed in oil bath for temperature control

    • Improved Accuracy

    • Fully Automatic

      • Bridge and RBC


    Thank you
    Thank you Confidence


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