Construction and application of platinum temperature sensors · Since then, platinum resistance thermo-meters have been used as indispensable devices for measuring temperature as

Data Sheet 90.6000 Page 1 / 11

JUMO GmbH & Co. KGDelivery address: Mackenrodtstraße 14,

36039 Fulda, GermanyPostal address: 36035 Fulda, GermanyPhone: +49 661 6003-0Fax: +49 661 6003-607e-mail: [email protected]: www.jumo.net

JUMO Instrument Co. Ltd.JUMO HouseTemple Bank, RiverwayHarlow, Essex CM 20 2TT, UKPhone: +44 1279 635533Fax: +44 1279 635262e-mail: [email protected]: www.jumo.co.uk

JUMO PROCESS CONTROL INC.885 Fox Chase, Suite 103Coatesville PA 19320, USAPhone: 610-380-8002

1-800-554-JUMOFax: 610-380-8009e-mail: [email protected]: www.JumoUSA.com

Introduction

As long as 130 years ago, Sir William Siemens made the suggestion that thechange of electrical resistance of metalsas a result of changes in temperaturecould be utilized for the measurement oftemperature itself. The material to beused should be a noble metal: platinum,since platinum shows characteristicsthat are not shared by other metals. In1886 Siemens continued to develop theplatinum resistance thermometer, and,by taking appropriate precautions, constructed a precision resistance thermometer that was suitable for measuring high temperatures.

Since then, platinum resistance thermo-meters have been used as indispensabledevices for measuring temperature as aphysical variable. These days, speciallyadapted designs make it possible to cover a multitude of applications over the temperature range from –200 to +850 °C. Platinum thermometerscan thus be used not only in industrialmeasurement technology, but in sectorssuch as HVAC engineering, householdequipment, medical and electricalengineering, as well as in automobiletechnology.

Wirewound platinum temperature sensors on a glass or ceramic core aswell as platinum chip sensors made inthin-film technology are incorporated asthe temperature-sensitive heart of theresistance thermometer.

Temperature-dependent resistance

Platinum temperature sensors use theeffect of the temperature-dependence ofthe electrical resistance of the noble metalplatinum. Since the electrical resistanceincreases with rising temperature, wespeak of a positive temperature coefficient(often abbreviated to PTC) for suchtemperature sensors.

In order to use this effect for measuringtemperature, the metal must vary itselectrical resistance with temperature in areproducible manner. The characteristicproperties of the metal must not changeduring operation, as this would result inmeasurement errors. The temperaturecoefficient should, as far as possible, beindependent of temperature, pressure andchemical influences.

Standardized platinum temperature sensors

For more than 130 years, platinum hasbeen the basic material of choice for tem-perature-dependent sensors. It has theadvantage that it is highly resistant to cor-rosion, is relatively easy to work (especiallyin wire manufacture), is available in a verypure state and exhibits good reproducibilityof its electrical properties. In order to main-tain the features noted above and to ensureinterchangeability, these characteristics aredefined in the internationally valid standardIEC 751 (translated in Germany as the DINEN 60 751).

This standard specifies the electrical resist-ance as a function of temperature (table ofreference values), permissible tolerances(as tolerance classes), the characteristiccurves and usable temperature range.

The characteristic curves are calculatedusing certain coefficients, whereby the cal-culation distinguishes between the temper-ature ranges from

–200 to 0 °C and from 0 to 850 °C.

The range –200 to 0 °C is covered by athird-order polynomial:

0,4�/ °C for Pt 100 temperature sensors

2,0�/ °C for Pt 500 temperature sensors

and

4,0�/ °C for Pt 1000 temperature sensors.

As an additional parameter, the standarddefines a mean temperature coefficientbetween 0 °C and 100 °C.

It represents the average change in resistance, referred to the nominal value at0 °C:

A second-order polynomial is applied forthe range 0 to 850 °C

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Construction and application of platinum temperature sensors

R (t) = R0 (1 + A x t + B x t2 + C x (t – 100 °C) x t3)

R (t) = R0 (1 + A x t + B x t2)

� = = 3.850x10–3°C–1R100 – R0

R0 x 100°Cwith the coefficients

The term R0 is referred to as the nominalvalue, and represents the resistance at0 °C.

According to EN 60 751, the nominal valueis 100.000 � at 0 °C. It is therefore referred to as a Pt 100 temperature sensor.

Temperature sensors with higher nominalvalues are also available on the market,such as Pt 500 and Pt 1000.

They have greater sensitivity, since theslope of the characteristic is directly proportional to R0, the nominal value.Their advantage thus lies in the fact thattheir resistance has a larger change withtemperature.

The resistance change in the temperaturerange up to 100 °C is approximately:

A = 3.9083x10–3°C–1

B = –5.775x10–7°C–2

C = –4.183x10–12°C–4R0 and R100 are the resistance values for the temperatures 0 °C and 100 °C respectively.

Calculating the temperature fromthe resistance

For the use as a thermometer, the resistance of the temperature sensor isused to calculate the corresponding temperature. The formulae cited abovedefine the variation in electrical resistanceas a function of temperature.

For temperatures above 0 °C, a closedform of the representation of the characteristic according to EN 60 751 canbe derived to determine the temperature.

Fig. 1: Pt100 characteristic

t =–R0 x A + [(R0 x A)2 – 4 x R0 x B x (R0 – R)]1/2

2 x R0 x B







R = resistance, measured in �

t = temperature, calculated in °C

R0, A, B = parameters as per EN 60 751

Tolerance limits

The standard distinguishes between twotolerance classes:

t = temperature, in °C (without math. sign)

The calculation of the tolerance limit �R in� at a temperature of t > 0 °C is given by:

For t < 0 °C it is:

Tolerance Class A applies for tempera-tures from –200 to +600 °C.

Tolerance Class B applies for the entiredefined range from –200 to +850 °C.

Fig. 2: Tolerance band as a function of the temperature

Extended tolerance classes

The two tolerance classes specified in thestandard are frequently inadequate forcertain applications. JUMO has defined afurther division of the tolerance classes,based on the standardized tolerances, inorder to cover the widest possible rangeof applications throughout the market.

In addition to the definition equations forthe temperature-dependent deviations,the range of validity has also been defined. Because of the inexactly linearrelationship between the resistance and temperature, measurements must be made at various temperatures to determine the deviations from the stand-ard curve 3 (for t >0 °C) or 4 (for t < 0 °C)respectively. For series manufacture oftemperature sensors, tests are generallymade only at 0 °C and 100 °C. So it is not

that the tolerance will be exceeded andthen the standard Class B tolerance mustbe applied.

Measurement point

Before delivery, all temperature sensors are completely checked and measured,

possible to make a precise determinationof the individual characteristic of a temperature sensor. Since, on the onehand, it is not possible to make the measurement uncertainty endlessly smalland, on the other hand, the characteristiccurve is subject to variations caused by production tolerances, the range ofvalidity of the narrower tolerance classesmust be restricted compared with themeasuring range of the temperature sensor.

Another conclusion from this situation isthat the temperature classes cannot benarrowed without limit.

Practical situation

Temperature sensors with tightened tolerances usually have a considerablywider measuring range. This has thepractical result that temperature sensorswhich are used at the upper or lower temperature limits can only achieve thegiven tolerance within the range of validity.Outside the range of validity, it is possible

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Class A: �t = � (0.15 + 0.002xltl)Class B: �t = � (0.30 + 0.005xltl)

�R = R0 (A + 2 x B x t) x �t

�R = R0 (A + 2 x B x t – 300°C x t2+4 x C x t3) x�t

Tolerance class Sensor category Temperature range Tolerance in °C

Class 1 / 3 DIN B Thin-film –50 to +200°C ± (0.10K + 0.0017 x Itl)Wire –70 to +250°C

Class A Thin-film –70 to +300°C ± (0.15K + 0.002 x Itl)Wire –200 to +600°C

Class B Thin-film –70 to +600°C ± (0.30K + 0.005 x Itl)Wire –200 to +850°C

Class 0.5 Thin-film –70 to +600°C ± (0.50K + 0.006 x Itl)Wire –200 to +850°C

Table 1: Tolerance classes – Temperature validity range Itl = measured temperature in °C (without sign)

Temper- Class Class Class Class ature 1/3 DIN A B 0.5

B

–200 °C 0.55 °C 1.30 °C 1.70 ° C

–70 °C 0.22 °C 0.29 °C 0.65 °C 0.92 °C

0 °C 0.10 °C 0.15 °C 0.30 °C 0.50 °C

100 °C 0.27 °C 0.35 °C 0.80 °C 1.10 °C

250 °C 0.53 °C 0.65 °C 1.55 °C 2.00 °C

350 °C 0.85 °C 2.05 °C 2.60 °C

600 °C 1.35 °C 3.30 °C 4.10 °C

850 °C 4.55 °C 5.60 °C

Table 2: ± Tolerance in °C according to class







and selected into tolerance classes. The measurement uncertainty of the classificati-on equipment is taken into account. Duringthe measurement, both the temperaturesensors and the connecting wires are at thespecific temperature for the measurement.Four-wire connections are made 2 mm fromthe open ends of the connecting wires.During further processing of the tempera-ture sensors it must be noted that anyalteration of the length of the connectingwires will alter the resistance for 2-wiremeasurement. In exceptional cases thismay cause the tolerance limits to beexceeded, positively or negatively.

Self-heating

In order to obtain an output signal from atemperature sensor, a current must flowthrough the sensor. This measuring currentgenerates heat losses which warm upthe temperature sensor. The result is an higher indicated temperature. Self-heatingdepends on various factors, one of which isthe extent to which the self-generated heatcan be removed by the medium being measured.

The formula for electrical power P = R x I2

means that this effect also depends onthe nominal resistance value (R) of the temperature sensor: For a given measuring current, a Pt 1000 temperaturesensor will generate 10 times as muchheat as a Pt 100. So the advantage of higher sensitivity brings the disadvantageof increased self-heating. If a temperaturerise of 0.1°C is permitted in running water,then the current level for wirewound ceramic temperature sensors will bebetween 3 and 50 mA, depending on thesize, and for thin-film temperature sensorsit will be about 1 mA.

In still air the permissible current level willhave to be reduced by a factor of about 50.If the temperature sensor is mounted in aprotective fitting, then the self-heating characteristics will be altered. The permissible current levels lie between thetwo extremes noted above, and depend on the thermal boundaries, size, heat conduction, and heat capacity of the pro-tective fitting.

Thermometer manufacturers often state aself-heating coefficient in the correspondingdocumentation. This coefficient provides avalue for the temperature increase causedby a defined power loss produced in thetemperature sensor. Such calorimetric measurements are carried out under de-fined conditions (in water flowing at 0.2

meters / sec or air at 2 meters / sec) but theresults have a somewhat theoretical natureand are used as figures of merit when comparing different types of construction.In most cases, the manufacturer defines themeasuring current as 1mA, since this valuehas proven to be an acceptable practicalvalue that does not generate a significantamount of self-heating.

For instance, if a 1 mA measuring current ispassed through a Pt 100 sensor mounted ina (thermally) completely insulated containerwith an air volume of 10 cm³, then the airwill be warmed up by about 39 °C after onehour.

Any flow of gas or liquid will reduce thiseffect, because of the considerably increased removal of the heat that is generated.

The self-heating must be measured at thepoint of installation, depending on the circumstance of the measuring setup. Thetemperature must be measured at variousdifferent current levels. The self-heatingcoefficient E can then be derived as follows:

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E = �t / (R x I2)

I = (�t / E x R) 1 / 2

Where �t = (indicated temperature) –(temperature of the medium), R = resist-ance of the temperature sensor, I = measuring current

The self-heating coefficient can then beused to define the maximum permissiblemeasuring current for a given permissiblemeasurement error �t.

Response

If the temperature sensor is subjected to asudden change in temperature, then therewill be a distinct time lag before it has takenup the new temperature. This time isdependent on the style of the temperaturesensor and the ambient conditions, such asthe medium being measured and the flowrate of the same. The figures given in thedata sheets refer to measurements in agita-ted water, at a flow of v = 0.4 meters / sec orin air at a flow of 1 meter / sec.

The response times for other media can becalculated with the aid of the heat transfercoefficient as per VDI / VDE 3522. Fig. 3shows a typical response curve (transferfunction).

The specific times derived are those takenby the sensor to reach 50 % or 90 % of thefinal (steady) value.

The transfer function, i.e. the way in whichthe measured value changes after a stepchange in temperature at the sensor, provides this information.

The transfer function is measured by passing a current of warm water or airacross the temperature sensor.

Two times (settling times) characterize thetransfer function:

– Half-value time t0.5This is the time taken for the measure-ment to reach 50 % of the final value, and the

– 90 % time t0.9 in which 90% of the final value is reached.

A time t, the time taken to reach 63.2 % ofthe final value, is not given, because it is

Fig. 3: Transfer function

Long-term behavior

In addition to the tolerance of the temper-ature sensor, the long-term behavior is animportant parameter, since it is the majorfactor determining the maintenance of themeasurement uncertainty during the oper-ating life of the device under its definedconditions. The values given in the datasheets are guidance values, determinedthrough measurements on the specifictype of sensor, not made-up in any way, inan oven with a normal atmosphere. Thefurther processing of the temperature sen-sors and the characteristics of the materi-als with which it comes into contact mayaffect the long-term stability. It is thereforeto be recommended that the long-termstability of a particular design should beestablished under the intended operatingconditions, so that external influencesmay also be taken into account.







easily mistaken for the time constant of anexponential function. The heat transferfunction of practically all temperature sen-sors shows significant deviations fromsuch a function.

Styles

Principally, platinum temperature sensorscan be divided into two fundamentally different categories. We can distinguishbetween temperature sensors with a solidwire winding in glass, ceramic or foil versions, and temperature sensors manufactured using the latest thin-filmtechnology. The classic platinum tempera-ture sensor is based on the wirewound

construction.

In spite of partially automated productionprocesses, a common feature of all suchstyles is a high level of manual labor inproduction.

Wirewound temperature sensors

Platinum-glass temperature sensors(PG style)

Platinum-glass temperature sensors belongto the category of wirewound construc-tions. One or two measurement windingsare wound on a glass rod, each in the formof a bifilar winding. The winding is fusedonto the glass and provided with connec-ting wires. The nominal resistance value iscalibrated by altering the length of the winding. Afterwards, a sleeve is pushedover the glass rod + measurement winding,and the components are then fusedtogether.

The glass that is used is matched to theexpansion coefficient of the platinum wire.An additional artificial ageing process ensu-res that good long-term stability is achie-ved. The operating temperature covers therange from –200 to +400 °C.

JUMO platinum-glass temperature sensorsare distinguished by a design that is extre-mely resistant to shock and vibration. Fur-thermore, the connecting wires exhibit avery high tensile strength. Another advantageof this style is that the temperature sensorscan readily be used for measurement in highly humid environments or directly in theliquid, thanks to the hermetic sealing of the

measurement winding and the excellentchemical resistance of the glass. In addit-ion, the familiar protection tube – a neces-sary component with other styles – can nowbe dispensed with, allowing short responsetimes.

A wide variety of platinum-glass temperaturesensors is available in many different geometries. As well as the versions with astandard nominal resistance of 100 � at 0 °C, JUMO also supplies platinum-glasstemperature sensors with 500 � and 1000 �nominal values, as well as special values onrequest. Versions with a glass extension ordouble measurement windings are alsopossible.

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Fig. 6: Producing temperature sensors under clean-room conditions

Fig. 7: Basic construction of platinum-glass temperature sensors (PG style)Fig. 5: Product selection

Fig. 4: Product selection

Connecting wires

Carrier rod(glass)

Bifilar platinum winding

Sheath







Platinum-glass laboratory resistance thermometers

Electrical glass thermometers for labora-tory applications frequently have to meetespecially high demands.

The electrical connection of the resistancethermometer is made via a connectorsystem (e.g. LEMOSA), or directly throughan attached cable. Connections can be made in 2-wire, 3-wire or 4-wire circuit, according to choice. Laboratory resistance thermometers can optionally be supplied in a variety of tolerance classes, such as the tighter tolerance of Class A as per EN 60 751. JUMO laboratory resistance thermometers canalso be delivered with a DKD calibrationcertificate.

As a specialist for manufacturing a wideproduct spectrum, JUMO offers solutionsfor many customer-specific requirements.

Platinum-ceramic temperature sensors(PK style)

Platinum-ceramic temperature sensorsuse a ceramic tube as the carrier material,in which there are either two or four bores,depending on the version to be produced.A platinum coil that has already been calibrated and fitted with connection wiresis inserted into each of the bores. Platinum-glass temperature sensors therefore also belong to the category ofwirewound constructions. The remainingspace in the bores is then filled withalumina powder, to fix the coils and toimprove heat transfer. Both ends of theceramic body are then closed with a sealing compound that is fused on. Thisseals off the embedded measurementwindings and also stabilizes the connecting wires. Platinum-ceramic temperature sensors are available withdiameters as small as 0.9 mm. Their over-

Laboratory resistance thermometers aremade by a supplementary processing of platinum-glass temperature sensors. Temperature sensors in the PGL style, forinstance, can be fitted with glass tubeextensions in various lengths. Dependingon the specific measurement task, suchglass extensions can also be suppliedwith a standard ground joint, diametergraduations, or even as angled versions.

all length varies, in general, from 4 to 30 mm. As far as the nominal value isconcerned, this style is normally only available with Pt 100 temperature sensors.

Platinum-ceramic temperature sensors aremainly used for high-temperature measu-rement. They have the highest overall usable temperature range, stretching from–200 to +800 °C.

The special internal construction of theplatinum-ceramic temperature sensors largely prevents permanent changes in theresistance value, which may occur in otherstyles as a result of substantial temperaturecycling or shock-like temperature changes.

However, the application of this style mustbe restricted if strong vibration or shocksare to be expected in the application.

Platinum-foil temperature sensors (PF style)

Like glass or ceramic temperature sensors,platinum-foil temperature sensors alsobelong to the category of wirewound styles. A winding of solid platinum wire isembedded between two self-adhesivepolyimide foils. The platinum winding iscalibrated through the adjustment of thewinding length, before the foils are joined.The electrical characteristics conform toEN 60 751. Two nickel tapes are taken outto form the electrical connection.

JUMO platinum-foil temperature sensors areespecially suitable for measurements on flat

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Fig. 10: Basic construction of platinum-ceramic temperature sensors (PK style)

Fig. 8: Basic construction of platinum-glasstemperature sensors with glass extension(style for laboratory resistance thermo-meters)

Connecting wires

Glass extension

Connecting wire extension

Glass temperature sensor PGV

End cap

Ceramic tube

End cap

Connecting wires

Platinum wire winding

Fig. 9: Automated production of wirewound platinum-glass temperature sensors







or even slightly curved surfaces. Furthermore,their flexibility and small thickness enablemeasurements at sites that are difficult toaccess. Thanks to their low intrinsic massand relatively large surface area, these foiltemperature sensors achieve fast response.Foil temperature sensors are designed for applications at temperatures from –80 to +180°C.

Thin-film temperature sensors

Since the early 80s, JUMO has taken production processes from semiconductortechnology and used them to manufactureplatinum-chip temperature sensors. Thiswas linked to the start of a continual process of miniaturization that is not yet atan end, even today, and is following tworoutes: a reduction of component sizesand an increase in nominal values, and,parallel to this technological development,a continual reduction of production costs,so that the technical advantages of plati-num-chip temperature sensors can alsobe used in mass production applications.

Platinum-chip temperature sensorswith connecting wires (PCA style)

Platinum-chip temperature sensors aremanufactured in the latest thin-film techniques, in clean-room conditions.Unlike the wirewound versions, the platinum layer in thin-film temperaturesensors is applied to a ceramic substratethrough a sputtering process.

This platinum coating is then formed into aserpentine structure by a photolithographicprocess, and then adjusted by a laser-trimming method.

The electrical connection is made throughspecial contact areas, onto which theconnecting wires are bonded. A fusedlayer of glass protects the platinum serpentine from external influences andalso serves as insulation.

The contact areas of the connecting wireson the sensor are fixed by another glasslayer, which also provides strain relief.

The temperature at which platinum-chiptemperature sensors can be used dependson the version, and is usually in the rangefrom –70 to +600 °C. Platinum-chip temperature sensors can also be used tosome extent at much lower temperatures,if they are previously given a specialartificial ageing treatment.

Thin-film temperature sensors combinethe favorable properties of a platinum sensor, such as interchangeability, long-term stability, reproducibility and widetemperature measurement range, with theadvantages of large-scale production.And, thanks to the small dimensions andlow mass, very fast response times are achieved. In addition, they can alsoachieve high nominal values in very smalldimensions, compared with glass andceramic temperature sensors.

Platinum-chip temperature sensorswith terminal clamps (PCKL style)

PCKL style platinum-chip temperature

sensors are manufactured in the sameway as the standard PCA styles. However,there are some differences in the connecting wire techniques that are used.

Compared with the standard PCA styletemperature sensors, these sensors do notfeature bonded connecting wires, but haveterminal clamps that are soldered on.

These terminal clamps are especially rigidand exhibit a high bending strength. Thischaracteristic gives the temperature sensors an outstanding directional stability.

PCKL style platinum-chip temperature sensors are thus preferred for various

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Fig. 13: Basic construction of platinum-chip temperature sensors with connectingwires (PCA style)

Fig. 12: Laser trimming of platinum-chiptemperature sensors

Strain relief

Covering layer

Bonding pad Structuredplatinum layer

Ceramic substrate

Connecting wires

Fig. 14: Basic construction of platinum-chip temperature sensors with terminalclamps (PCKL style)

Covering layer

Solder contact

Terminal clamps

Structured platinum layer

Ceramic substrate

Fig. 11: Basic construction of platinum-foiltemperature sensors (PF style)

Foil

Platinumwinding

Connecting tapes

Foil







types of probe construction in climaticmeasurement technology. The entire tem-perature sensor, including the solder jointand terminal clamps (with bare wire ends),is additionally coated with a protectivevarnish, to protect against condensationand external effects.

The operating temperature range is –40 to +105 °C.

Platinum-chip temperature sensorsin cylindrical style (PCR style)

Platinum-chip temperature sensors on epoxy card (PCSE style)

PCSE style platinum-chip temperature sensors constitute a pre-assembled version. The epoxy card carries an assem-bled SMD temperature sensor as the activecomponent to acquire the temperature. Theresistance signal is transmitted to thecontact surfaces on opposing sides, via

Platinum-chip temperature sensors inSMD style (PCS style)

Platinum-chip temperature sensors in SMDstyle belong to the category of thin-filmtemperature sensors. Like the similarlydesigned PCA styles, they are manufac-tured in the latest thin-film techniques, inclean-room conditions. During productionof these temperature sensors, a platinumlayer, which constitutes the active layer, isformed into a serpentine structure andapplied to a ceramic substrate.

The platinum serpentine is provided withtwo solder contacts at the opposing lengthwise ends of the temperature sen-sor, to make the electrical connection. Theglass layer that is applied after the adjust-ment protects the platinum serpentineagainst external effects.

Unlike wire-ended styles, SMD temperaturesensors are specially designed for auto-matic placing on electronic circuit boardsin large-scale production.

thin tracks. At these points, a variety ofconnecting wires can be attached for arange of wire-ended probe versions. Theuse of this style (with a base card) has theadvantage that any possible tension on theconnecting cable cannot be transmitteddirectly to the temperature sensor. Further-more, the thin conductor tracks achieve aconsiderable reduction of any measure-ment error caused by heat conduction.

This style was designed especially as ameasuring insert, making it considerablyeasier to fabricate different versions ofwire-ended probes. This also enables auto-mated production steps, thus achieving thelowest possible cost levels.

PCSE style platinum-chip temperature sensors are suitable for operation over atemperature range from –20 to +150 °C.

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Fig. 15: Basic construction of platinum-chip temperature sensors in cylindricalform (PCR style)

Fig. 16: Basic construction of platinum-chip temperature sensors in SMD form(PCS style)

Fig. 17: Basic construction of platinum-chip temperature sensors on epoxy card(PCSE style)

Ceramic tube

Thin-film temperature sensor

Sealing

Covering layer

Structured platinum layer

Ceramic substrate

Cap (solder contact)

Spacer

SMD temperature sensor

Base card

Basically, this style incorporates a plati-num-chip temperature sensor which isinserted into a ceramic sleeve that is openat one end. After inserting the platinum-chip temperature sensor, the opening ofthe ceramic sleeve is hermetically sealedwith a sealing compound. The round bodyof this type of platinum-chip temperaturesensor enables a good adaptation to theinner walls of protection tubes, and alsoprotects the sensor from external influ-ences. In addition, this style exhibits highmechanical rigidity, thus facilitating anembedding in many types of bulk adhe-sive. It is frequently used in the construc-tion of equipment and machinery.

JUMO temperature sensors in cylindricalstyle present a cost-effective alternative towirewound ceramic temperature sensors.Platinum-chip temperature sensors in thiscylindrical style are designed for operatingtemperatures from –70 to +300 °C.







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Electrical Temperature Measurement

with thermocouples and resistancethermometersby Matthias Nau

makes this book a valuable guide, both forthe experienced practical engineer and forthe novice in the field of electrical tempe-rature measurement.

To be ordered under Sales No.90 / 00085081 or as a download fromwww.jumo.net

Schools, institutes and universities areasked to make joint orders, because ofthe high handling costs.

Error Analysis of a Temperature Measurement System with worked examplesby Gerd Scheller

The 44-page publication helps in the evaluation of measurement uncertainty,particularly through the worked examplesin Chapter 3. Where problems arise, weare happy to discuss specific problemswith our customers, and to provide practical advice.

In order to make comparable measure-ments, their quality must be establishedthrough details of the measurement uncertainty. The ISO / BIPM “Guide to theExpression of Uncertainty in Measure-ment”, published in 1993 and usually referred to as GUM, introduced a standar-dized method for the determination anddefinition of measurement uncertainty.This method was adopted by calibrationlaboratories around the world. However,the application requires a certain level ofmathematical understanding. Furtherchapters present the topic of measure-ment uncertainty in a simplified and easilyunderstandable fashion for all users oftemperature measurement systems.

Errors in the installation of the temperaturesensors and the connections to the evaluation electronics lead to increasederrors in measurement. To these must beadded the measurement uncertainty components of the sensor and the evalua-tion electronics itself. The explanation ofthe various components of measurementuncertainty is followed by some workedexamples.

Knowledge of the various measurementuncertainty components and their magnitudes enables the user to reduceindividual components through the selection of equipment or altered installa-tion conditions. The decisive factor is

01.05/ 00307266

Fig. 19: Publication“Error Analysis of a Temperature Measure-ment System with worked examples”

Fig. 18: Publication“Electrical temperature measurement withthermocouples and resistance thermo-meters”

Electrical temperature sensors havebecome indispensable components inmodern automation, consumer goodsand production technology. Particularlyas a result of the rapid expansion ofautomation in recent years, they havebecome firmly established in industrialengineering.

In view of the large spectrum of productsavailable for the electrical measurementof temperature, it is becoming ever moreimportant for the user to select the onesuitable for his application.

On 160 pages this publication deals withthe theoretical fundamentals of electricaltemperature measurement, the practicalconstruction of temperature sensors, theirstandardization, electrical connection,tolerances and types of construction.

In addition, it describes in detail the different fittings for electrical thermo-meters, their classification according toDIN standards, and the great variety ofapplications. An extensive section oftables for standard values of voltage andresistance according to DIN and EN

always, which level of measurementuncertainty is acceptable for a specificmeasurement task. For instance, if a stan-dard specifies tolerance limits for thedeviation of a temperature from a givenvalue, then the measurement uncertaintyof the method used for temperature mea-surement should not exceed 1 / 3 of thetolerance.

To be ordered under Sales No.90 / 00413510 or as a download fromwww.jumo.net








German Calibration Service (DKD)at JUMO

Certification laboratory for temperature

Raised quality expectations, improvedmeasurement technology and, of course,quality assurance systems such as ISO9000, make increasing demands on thedocumentation of processes and themonitoring of measuring equipment. Tothis must be added customers' demandsfor products with a high standard of quali-ty. Particularly stringent demands arisefrom the ISO 9000 and EN 45 000 standards, whereby measurements mustbe traceable to national or internationalreference standards. This provides thelegal basis for obliging suppliers andmanufacturers (of products that are subject to processes where temperature isrelevant) to check all test and measure-ment equipment that can affect the product quality, before use or at prescribed intervals. Generally, this isdone by calibration or adjustment usingcertified equipment. Because of the highdemand for calibrated instruments andthe large number of instruments to be calibrated, the state laboratories haveinsufficient capacity. The industry has therefore established and supports specialcalibration laboratories which are linked tothe German Calibration Service (DKD)and, in matters of measurement technology,subordinate to the Physikalisch-Techni-sche-Bundesanstalt (PTB).

The certification laboratory of the GermanCalibration Service at JUMO has carriedout calibration certification for temperaturesince 1992. This establishment providesfast and economical certification as a service for everyone.

DKD calibration certificates can be issuedfor resistance thermometers, thermo-couples, direct-reading measurement sets, data loggers, temperature block calibrators and temperature probes withbuilt-in transmitters, within the range –80 to +1100 °C. The traceability of thereference standard is the central issuehere. All DKD calibration certificates aretherefore recognized as documents of traceability, without any further specifica-tions. The DKD calibration laboratory atJUMO has the identification DKD-K-09501-04 and is accredited to DIN ENISO / IEC 17 025.

You can get a free brochure (at presentonly available in German) by asking forPublication No. PR 90029 or as a down-load from www.jumo.net.

Practical assistant for everyday use

“Standard values for thermocouple andresistance thermometers”

at present only available in German

This is a practical assistant for use inlaboratories, production, service and training, and includes the standard reference values for thermocouple typesJ, K, T, N, S, R and B as per EN 60 584and for Pt 100 resistance thermometersaccording to EN 60 751.

It enables you very quickly to assign a temperature value to every resistance valueor thermal emf - or the other way around.

The pocket slide-rule, the interchangeabletables of data, color-coded according to theelements, and the corresponding operatinginstructions are all in wipe-down plastic.And everything is held in a clear plasticpocket, to prevent it becoming dirty.

The WINDOWS calculation program (on adiskette) generates the standard valuesaccording to freely selectable temperaturelimits and increments. These tables canalso be exported for further processing inother applications.

In addition, the resistance value, thermal

emf and tolerance class (as defined by thestandard) can all be determined for anyvalue of temperature. Alternatively, the corresponding temperature can be calculated from the known value of the sen-sor signal.

Furthermore, the individual characteristiccurve parameters for resistance thermo-meters can be programmed and saved. Allthe usual calculation options are providedfor this purpose.

Pocket slide rule

To be ordered under Sales No.90/0034111. (Article only available in German at present)

3 ½" diskette version

To be ordered under Sales No.90/00341183 or as a download fromwww.jumo.net (Article only available inGerman at present)


01.05/ 00307266

Fig. 20: Pocket slide rule and WINDOWS programPractical assistant for everyday use“Standard values for thermocouple and resistance thermometers”

Documents

Construction and application of platinum temperature sensors · Since then, platinum resistance thermo-meters have been used as indispensable devices for measuring temperature as