ZMD31050 Temperature Sensing with Platinum-Resistors (RTD s)

Temperature Sensing with Platinum-Resistors (RTD s) /

Brief Description Temperature is one of the most common physical measurands. For industrial applications thermocouples and Platinum-based resistive temperature sensors (RTDs) are typically used to measure temperatures. The can be used in order to condition the temperature signal of both types of sensors. The is a programmable system-onchip (PGA; ADC; DSP; DAC) and optimized for industrial sensing applications, thus industrial temperature transmitters can be designed with a very low number of electronic parts at low system cost and with high performance. The can be programmed to output analog signals (e.g. (0 to 10) VDC; (4 to 20) ma; PWM) as well as digital values via a serial interface (I 2 C or SPI or ZACwire). Because of the fully digitized calibration procedure the cost for calibration are minimized, compared to manual adjustment. This digital calibration procedure can be automated, thus an integration of the calibration line in a high-volumeproduction line is possible. This application note describes the use of for signal conditioning of Platinumbased resistive temperature sensors (RTDs). Three standard applications are described in detail with digital I2C-interface, with analog voltage output and with analog current loop output. The range of temperature to be measured amouts to (-200 to +800) C, the achievable resolution of the temperature signal amounts to 14 bit in maximum (via digital interface). Basically the principle of signal conditioning implemented in the can be used for other types of resistive temperature sensors with positive temperature coefficients (PTCs) as well (e.g. Nickel- or semiconductor-based PTCs). Even a simple copper wire could be used as temperature sensor. Some tables with material constants of Platinum an Nickel are attached. Benefits Precise and cost effective temperature measurement using Pt100, Pt1000 and other resistive PTC temperature sensors High accuracy Interchangeable sensor element Calibration via characteristic curve of resistance (not over temperature) Only digital communication during calibration fast, precise, robust Low system cost and high measurement performance Fits perfect to cost-sensitive industrial high-volume-applications Features Digital correction of offset, span and (non)- linearity Compatible to usual PTC temperature sensors like Pt100, Pt1000, Ni, Cu or auch semiconductor-based sensors (KTY) Wide range of temperature measurement (-200 to +850) C using Pt-based sensors Analog output options: ratiometric voltage (2.5 to 97.5) %V supply absolute voltage (0 to 1/5/10 V) 2-wire-current loop (4 to 20) ma Digital interfaces: I 2 C, SPI or ZACwire TM (proprietary digital one-wire-interface) Programmable switch outputs Operational temp. range (-40 to +150) C two user-programmable EEPROM cells, e.g. for part-id-number 2 / 27

Content Content... 3 List of figures... 4 List of tables... 4 1 Temperature Measurement with... 5 2 Input circuitry with PTC... 6 2.1. Resistive Voltage Divider (half bridge)... 6 2.2. Resistive voltage divider (full bridge)... 7 2.3. Input circuitry with external current source... 9 3 Application circuit with I 2 C-interface & voltage output... 11 4 Application Circuit with voltage output (0 to 10) VDC... 12 5 Application Circuit with current loop output (4 to 20) ma... 13 6 Adjustments at the -Evaluation-Software... 14 General remarks... 16 6.1. Calibration via characteristic curve of resistance... 16 6.2. Calibration in a bath... 16 7 Appendix... 17 7.1. Theoretical basics of Platinum sensors... 17 7.1.1. Packages... 17 7.1.2. Sensor signal processing... 18 7.1.3. Accuracy classes... 18 7.1.4. Characteristic curves of Pt-based sensors according to DIN/EN 60751... 19 7.1.5. Characteristic curves of Ni-based sensors according to DIN/EN 43760... 20 7.2. Pt100 resistance table according to DIN/EN 60751... 21 7.3. Links... 24 7.4. Manufacturer of Pt and Ni based resistive temperature sensors... 24 8 Further documents... 25 9 Glossary... 26 10 Document Revision History... 27 3 / 27

List of figures figure 1 input circuitry half bridge... 6 figure 2 input circuitry full bridge... 7 figure 3 Input circuitry with external current source... 9 figure 4 Application circuit with I 2 C-interface and voltage output... 11 figure 5 application circuit (0 to 10) VDC... 12 figure 6 application circuit with 2-wire-current-loop-output signal (4 to 20) ma... 13 figure 7 Adjustments in the main window of the -Eval.-Software... 14 figure 8 Sub-window current-loop-calibration-adjust... 15 figure 9 Sub-window Sensor-Calibration... 15 figure 10 Pt1000 of thin-film-technology... 17 List of tables table 1 temperature-related output voltage of the half bridge... 7 table 2 temperature-related output voltage of the full bridge... 8 table 3 temperature-related output voltage of the constant current circuitry... 10 table 4 value ranges, calibration points and output signal of the temperature transmitter... 14 table 5 Pt100 resistance values at the temperature range (-200 to +850) C... 21 table 6 Further documents... 25 table 7 Glossary... 26 table 8 Revision... 27 4 / 27

1 Temperature Measurement with Temperature is one of the most common physical measurands. For industrial applications thermocouples and Platinum-based resistive temperature sensors (RTDs) are typically used to measure temperatures. The can be used in order to condition the temperature signal of both types of sensors. The is a programmable system-on-chip (PGA; ADC; DSP; DAC) and optimized for industrial sensing applications, thus industrial temperature transmitters can be designed with a very low number of electronic parts at low system cost and with high performance. The can be programmed to output analog signals (e.g. (0 to 10) VDC; (4 to 20) ma; PWM) as well as digital values via a serial interface (I2C or SPI or ZACwire). Because of the fully digitized calibration procedure the cost for calibration are minimized, compared to manual adjustment. This digital calibration procedure can be automated, thus an integration of the calibration line in a high-volume-production line is possible. This application note describes the use of for signal conditioning of Platinum-based resistive temperature sensors (RTDs). Three standard applications are described in detail with digital I2C-interface, with analog voltage output and with analog current loop output. The range of temperature to be measured amounts to (-200 to +800) C, the achievable resolution of the temperature signal amounts to 14 bit in maximum (via digital interface). Basically the principle of signal conditioning implemented in the can be used for other types of resistive temperature sensors with positive temperature coefficients (PTCs) as well (e.g. Nickel- or semiconductor-based PTCs). Even a simple copper wire could be used as temperature sensor. Some tables with material constants of Platinum an Nickel are attached. 5 / 27

2 Input circuitry with PTC 2.1. Resistive Voltage Divider (half bridge) PTC sensors are resistive elements, their electrical resistance increases with increasing temperature. In General all metallic materials have such a positive temperature coefficient of their electrical resistance. Platinum and Nickel are most commonly used for temperature sensors in practice. Because of the very flexible, programmable analog front end of the there are various options in order to measure the resistance of the temperature sensor. The simplest configuration (refer figure 1) consists of two resistors and the sensor element. The resistors are referred to the supply voltage and the PTC is connected between these two resistors in series. Because of its inherent symmetry of this voltage divider the voltage drop of the PTC amounts to values within the common mode voltage range of the s differential input amplifier. The voltage drop of the sensor element is ratiometric to the supply voltage and proportional to its resistance. figure 1 input circuitry half bridge This circuitry can be used for a wide range of temperature measurement at low and medium signal resolution. The relative high offset resistance causes a high offset voltage, thus the conversion range of the ADC inside the needs to be adapted to this by adjusting the ADC range shift e.g. to 15/16 instead of the default value of 1/2 (differential input voltage range symmetrical to 0 mv). A disadvantage of this circuitry is, that the sensor element and its connection wires need to be isolated properly, because it is not reffered to GND. In order to avoid additional, temperature-related errors it is recommended to use low-tc-resistors (e.g. with 50 ppm/k or 25 ppm/k) fot the voltage divider. These resistors should be of the same batch in order to get the best common mode performance. The current flowing through the resistive divider must be limited to approx. 0.25 ma at a Pt1000 sensor element in order to avoid an additional error caused by self heating. 6 / 27

table 1 temperature-related output voltage of the half bridge Temperature [ C] Sensor resistance [Ω] Output voltage [mv @ VDD=5V] Output voltage [mv / V] -100 602,6 146,2 29,2-20 921,6 220,3 44,1 0 1000 238,1 47,6 20 1077,9 255,7 51,1 50 1194,0 281,7 56,3 100 1385,1 323,8 64,8 200 1758,6 404,1 80,8 400 2470,9 549,8 110,0 800 3757,0 790,7 158,1 2.2. Resistive voltage divider (full bridge) At this input circuitry the PTC sensor element is connected to full-bridge-voltage-divider (WHEATSTONE bridge refer figure 2). The advantage compared to the half bridge configuration is, that the sensor element is connected to GND. The offset voltage can be subtracted, but the output voltage to be processed by the is ratiometric to the supply voltage and proportional to the PTC s resistance as before. figure 2 input circuitry full bridge 7 / 27

The full bridge consists of four metal-film-resistors of 10 kohm (TC = 50 ppm/k) each of the same batch. The low end resistance of one half bridge is adapted to the PTC by another resistor connected in parallel (refer figure 2 / resistor R5). When using a Pt1000 sensor element a value of R5 = 91 kohm is recommended in order to achieve a resulting low end resistance of this half bridge of approx. 10 kohm and, thus, a balanced full bridge. By this the offset voltage amouts to near zero and the achievable ADC resolution of the becomes maximal. When using a digital output mode a resolution of the temperature signal of 14 bit can be achieved. Hint: The advantage of the connection of R5 = 91 kohm in parallel to R4 (refer figure 2) is, that the higher TC of this resistor is weighted by only 10% when calculation the total error caused by the TCs of the bridge resistors. The value of R5 = 91 kohm is valid for temperatures to be measured > 0 C, at very low or high temperatures to be measured the value of R5 need to be adapted probably. The ADC range shift should be adjusted to 15/16 at temperatures to be measured > 0 C in order to achieve the maximal sensor signal resolution. table 2 temperature-related output voltage of the full bridge Temperature [ C] Sensor resistance [Ω] Output voltage [mv @ VDD=5V] -100 602,6-49,4-9,9-20 921,6-8,6-1,7 0 1000 1,2 0,2 20 1077,9 10,9 2,2 50 1194,0 25,2 5,0 100 1385,1 48,4 9,7 200 1758,6 92,5 18,5 400 2470,9 172,3 34,5 800 3757,0 303,8 60,8 Output voltage [mv / V] 8 / 27

2.3. Input circuitry with external current source The disadvantage of the half/full bridge voltage divider circuitries described before is, that the resistance of the connecting wires influences the temperature signal to be processed by. This effect could be compensated by calibration, but afterwards the length of the connecting wires cannot be changed without loss of accuracy. To avoid this the so-called 4-wire-force-sense -principle is used. Via two wires the sensor element is supplied by a constant current, via the other two wires the resulting voltage drop at the sensor element ist measured. By using a constant current variations of the resistance of the connecting wires cannot influence the voltage drop at the sensor element anymore. When using this circuitry the connecting wires to the sensor element need to be isolated properly, because there is no connection between the sensor element and e.g. GND. The low end resistance of the constant current source (refer figure 3 R3) causes an offset voltage, which shifts the voltage drop of the sensor element to the input common mode range of the. This voltage drop is proportional to the resistance of the sensor element. The conversion range of the ADC inside the needs to be adapted to the sensor signal offset by adjusting the ADC range shift e.g. to 15/16 instead of the default value of 1/2 (differential input voltage range symmetrical to 0 mv) in order to enable the maximal ADC resolution of the sensor signal. figure 3 Input circuitry with external current source Hint: There is a programmable constant current source inside the, which could be used as well fort his application. For highly accurate applications it is recommended to use a very stable external constant current source. When using long connection wires it is recommended to use RF filters in order to improve the susceptibility of the input circuitry vs. RF signals. This circuitry can be used for Pt100 sensor elements as well. The low end resistance needs to be adapted for that in order to adjust a constant current of approx. 1 ma. 9 / 27

table 3 temperature-related output voltage of the constant current circuitry Temperature [ C] Sensor resistance [Ω] Output voltage [mv @ VDD=5V] Output voltage [mv / V] -100 602,6 150,7 30,1-20 921,6 230,4 46,1 0 1000 250,0 50,0 20 1077,9 269,5 53,9 50 1194,0 298,5 59,7 100 1385,1 346,3 69,3 200 1758,6 439,7 87,9 400 2470,9 617,7 123,6 800 3757,0 939,3 187,9 10 / 27

3 Application circuit with I 2 C-interface & voltage output figure 4 Application circuit with I 2 C-interface and voltage output By this circuitry the conditioned temperature signal can be output via a digital serial interface (I2C or ZACwire protocol) at a very high resolution. The measurement range amounts to (-200 to +850) C at approx. 14 bit resolution, which is equal to a temperature resolution of better than 0.1 Kelvin. Additionally an analog voltage output signal of 11 bit in resolution is available. To get a ratiometric analog voltage output signal the depletion-nmos-transistor TR2 needs to be replaced by a short. By this tolerances or a drift of the supply voltage cannot influence the conditioned output signal because of the full ratiomentric mode of signal processing. 11 / 27

4 Application Circuit with voltage output (0 to 10) VDC figure 5 application circuit (0 to 10) VDC By the external circuitry drawn at figure 5 above an additional discrete output buffer is build, which converts the analog output voltage range to e.g. (0 to 10) VDC. The protection parts enable the use of this application circuit inside temperature transmitters used e.g. for building automation applications. 12 / 27

5 Application Circuit with current loop output (4 to 20) ma figure 6 application circuit with 2-wire-current-loop-output signal (4 to 20) ma By the external circuitry drawn at figure 6 above an additional discrete output buffer is build, which converts the analog output voltage range to a current signal (4 to 20) ma. The protection parts enable the use of this application circuit inside temperature transmitters used for industrial applications. 13 / 27

6 Adjustments at the -Evaluation-Software The following example describes the adjustment and the calibration of a temperature transmitter with Pt1000 sensor element and analog (4 to 20) ma current loop output mode. The input circuitry drawn in chapter 5 is used, the temperature range to be measured amounts to (-20 to 80) C. table 4 value ranges, calibration points and output signal of the temperature transmitter Temperature [ C] R_Sensor [Ω] V_Bridge [mv] Output [%] I_loop [ma] L min -20 921,6-8,6 20,00 4,00 P1 0 1000,0 1,2 36,00 7,20 P3 30 1116,7 15,7 60,00 12,00 P2 60 1232,4 29,9 84,00 16,80 L max 80 1309,0 39,2 100,00 20,00 figure 7 Adjustments in the main window of the -Eval.-Software 14 / 27

figure 8 Sub-window current-loop-calibration-adjust figure 9 Sub-window Sensor-Calibration 15 / 27

General remarks Sensor supply current: Bei When using Pt1000 sensors their supply current must be adjusted to < 0.3 ma in order to avoid additional errors caused by self heating effects. Connection wires: When using a 2-wire-connection the resistance of the connecting wires becomes part of the processed sensor resistance. At wire length < 0.2 m this effect can be disregarded (e.g. at head transmitters). At longer connection wires their resistance should be measured and embedded to the calibration by adding this resistance value to the resistance values of the sensorelement acquired during calibration. If the calibration is performed over temperature using a calibration bath, then the resistance of the connection wires is embedded in the calibration. After calibration the length of this connection wire must not be changed anymore. Temperature compensation of conditioning electronic circuitry: Because of the distance between the temperature sensor element and the conditioning electronics an additional, but relatively small error could be caused by e.g. self heating of the electronics or variant ambient temperatures at the electronics. In order to avoid errors cause by the TC of the resistors of the input circuitry metal-film-types of the same batch with TC = 50 ppm/k or TC = 25 ppm/k must be used. The TC of a Pt1000 sensor element amounts to 3850 ppm/k, thus there is still a small temperature-related error caused by the input circuitry. Furthermore the small, temperature-related error of the analog front end of needs to be added as well. Theoretically it would be possible to measure the ambient temperature of the conditioning electronics itself and to calibrate the electronics at several operating temperatures using a climate chamber. But this would cause very high calibration cost. In practice this is not necessary at common accuracy requirements. 6.1. Calibration via characteristic curve of resistance The characteristic curve of resistance of a Pt1000 sensor element is standardized according to DIN/IEC 60751. The maximal allowed tolerance between temperature and resistance is classified and amounts at class A sensors to 0.15 Kelvin and at class B sensors to 0.3 Kelvin (related to 0 C). This enables a calibration of temperature transmitters using this standardized characteristic curves of Pt1000- resistance, which makes the calibration under the conditions of high-volume production very cost effective. To calibrate the 2nd-order-polynomial-math of three calibration points are needed. These three points of resistance values can be stimulated at the input of the DUT (Device Under Test) by a resistive decade. The calibration points should be defined in a way, that one point is located at the lower end of the measurement range (below 30% full scale), the second point within the upper end of the measurement range (> 30% full scale) and the third point at around 50% full scale. Later on at these calibration points the maximal accuracy will be achieved. 6.2. Calibration in a bath At very high requirements regarding accuracy it is recommended to calibrate the temperature sensor element together with the connecting wires and the conditioning electronics in a calibration bath. By this all temperature-related errors of the sensor element, of the connecting wires and of the conditioning electronics can be compensated, if the thermal coupling between the sensor element and the conditioning electronics is very good. 16 / 27

7 Appendix 7.1. Theoretical basics of Platinum sensors The use of resistive Platinum-based temperature sensors for industrial temperature sensing applications ist he most common principle for the accurate measurement of temperatures of (-200 to +800) C. In former times there were wounded types of sensors available, which were of high cost. Today most of these sensors are by thin film technology, which enables smaller dimensions, shorter response time, lower cost and higher precision. The resistance of such a sensor element depends on temperature, the characteristic curve is standardized according to DIN/EN 60751. This enables the interchange of sensorelements of the same type and class without a new calibration. At raw approximation the resistance of Platinum-based temperature sensors depends in a linear mannor on temperature. More accurate approximations use a 2 nd -order-polynom to model this characteristic at temperatures > 0 C. For temperatures < 0 C another polynom of 4th order can be used in order to achiev high precision. 7.1.1. Packages Sensors with THT-compatible, wired packages can be used to build transducers, pocket thermometers or other specific systems with glued or potted sensors. The wires can be soldered, but should be welded when measuring temperatures > 150 C. Sensors with SMT-compatible packages can be mounted directly on a PCB or other substrates using common pick-and-place-machines and soldering processes. At high volume such parts are of very low cost. Typical applications are room probes or temperature compensation at electronic circuits. figure 10 Pt1000 of thin-film-technology 17 / 27

Thin-film-RTDs are manufactured in high volume. On a ceramic substrate a thin Platinum layer is applied using vapor phase deposition technology. Afterwards this Pt layer is structured like a meander using lithographic techniques. By laser trimming the required target value of the resistance is adjusted. Pt100: Because of ist low resistance of typ. 100 Ohms this sensor type should be interfaced using the 3- or 4-wire- force-sense -configuration with a supply current < 1 ma in order to decrease self-heating related errors. Pt1000: The processing of Pt100-signals is more simple because of the higher resistance of typ. 1000 Ohms, only a 2-wire-connection is needed normally. When using long connection wires it is recommended to compensate their resistance. Beside these two types of Pt-based sensors there are further Pt-based types available with various resitances, e.g. very low-ohmic types of 25 Ohms or high-ohmic types of 10 kohms. Connecting wires: When measuring high temperatures it is recommended to use Nickel-Platinumconnecting wires. 7.1.2. Sensor signal processing The processing of the sensor resistance is done usually by measuring the voltage drop at the sensor element while it is supplied by a constant current. By this the measured change of this voltage drop is at a first approximation proportional to the change of the sensor element s resistance to be detected. The value of the constant sensor supply current needs to be adjusted carefully in order to achieve the optimal measurement performance (sensor signal span vs. self heating). The other practicable option is to use the full-bridge-input-circuitry. This enables to connect the sensor element to GND at one end. 7.1.3. Accuracy classes Because of techology-related tolerances Pt-based temperature sensors are classified to class A and class B. These classes decribe the dependence of the allowed temperature error T on the real temperature T to be measured. error specification of the classes A and B [ C]: class A: T = ± (0,15 C + 0,002 T) class B: T = ± (0,30 C + 0,005 T) 1/3 class B: T = ± (1/3 (0,30 C + 0,005 T)) 1/10 class B: T = ± (1/10 (0,30 C + 0,005 T)) The higher accuracy of sensor elements of 1/3 class B and 1/10 class B is typically specified for a smaller temperature range compared to the allowed total range of temperature, which could be measured. 18 / 27

7.1.4. Characteristic curves of Pt-based sensors according to DIN/EN 60751 The resistance of a Platinum-based temperature sensor at a certain temperature can be calculated based on its standardized resistance R0 according to the following formulas: For the temperature range (0 to +100) C a linearly approximated formula (1st-order-polynom) can be used: R = R0 (1 + a T) with T in C a = 3,85 10-3 / K For the temperature range (+100 to +850) C or at very high accuracy for T = (0 to +100) C a quadratically approximated formula (2nd-order-polynom) can be used: R = R0 (1 + a T + b T 2 ) with T in C a = 3,9083 10-3 / K b = -5,775 10-7 / K 2 For the temperature range < 0 C a 4th-order-polynom is used: R = R0 (1 + a T + b T 2 + c (T 100 C) T 3 ) with T in C a = 3,9083 10-3 / K b = -5,775 10-7 / K 2 c = -4,183 10-12 / K 4 19 / 27

7.1.5. Characteristic curves of Ni-based sensors according to DIN/EN 43760 The resistance of a Nickel-based temperature sensor at a certain temperature can be calculated based on its standardized resistance R0 according to a 6 th -order-polynom: R = R0 (1 + a T + b T 2 + c T 3 +d T 4 + e T 5 + f T 6 ) coefficients of Nickel NL (5000 ppm/k): a = 4,427 10-3 / K b = 5,172 10-6 / K 2 c = 5,585 10-9 / K 3 d = 0 e = 0 f = 0 coefficients of Nickel ND (6180 ppm/k): a = 5,485 10-3 / K b = 6,65 10-6 / K 2 c = 0 d = 2,805 10-11 / K 4 e = 0 f = -2,0 10-17 / K 6 coefficients of Nickel NJ (6370 ppm/k) a = 5,64742 * 10-3 / K b = 6,69504 * 10-6 / K 2 c = 5,68816 * 10-9 / K 3 d = 0 e = 0 f = 0 coefficients of Nickel NA (6720 ppm/k) a = 5,88025 * 10-3 / K b = 8,28385 * 10-6 / K 2 c = 0 d = 7,67175 * 10-12 / K 4 e = 0 f = -1,5 * 10-16 / K 6 20 / 27

7.2. Pt100 resistance table according to DIN/EN 60751 At Pt1000 temperature sensors the values of this table need to be multiplied by factor 10. table 5 Pt100 resistance values at the temperature range (-200 to +850) C 0 1 2 3 4 5 6 7 8 9 10-200,00 18,52 18,95 19,38 19,82 20,25 20,68 21,11 21,54 21,97 22,40 22,83-190,00 22,83 23,25 23,68 24,11 24,54 24,97 25,39 25,82 26,24 26,67 27,10-180,00 27,10 27,52 27,95 28,37 28,80 29,22 29,64 30,07 30,49 30,91 31,34-170,00 31,34 31,76 32,18 32,60 33,02 33,44 33,86 34,28 34,70 35,12 35,54-160,00 35,54 35,96 36,38 36,80 37,22 37,64 38,05 38,47 38,89 39,31 39,72-150,00 39,72 40,14 40,56 40,97 41,39 41,80 42,22 42,63 43,05 43,46 43,88-140,00 43,88 44,29 44,70 45,12 45,53 45,94 46,36 46,77 47,18 47,59 48,00-130,00 48,00 48,42 48,83 49,24 49,65 50,06 50,47 50,88 51,29 51,70 52,11-120,00 52,11 52,52 52,93 53,34 53,75 54,15 54,56 54,97 55,38 55,79 56,19-110,00 56,19 56,60 57,01 57,41 57,82 58,23 58,63 59,04 59,44 59,85 60,26-100,00 60,26 60,66 61,07 61,47 61,88 62,28 62,68 63,09 63,49 63,90 64,30-90,00 64,30 64,70 65,11 65,51 65,91 66,31 66,72 67,12 67,52 67,92 68,33-80,00 68,33 68,73 69,13 69,53 69,93 70,33 70,73 71,13 71,53 71,93 72,33-70,00 72,33 72,73 73,13 73,53 73,93 74,33 74,73 75,13 75,53 75,93 76,33-60,00 76,33 76,73 77,12 77,52 77,92 78,32 78,72 79,11 79,51 79,91 80,31-50,00 80,31 80,70 81,10 81,50 81,89 82,29 82,69 83,08 83,48 83,87 84,27-40,00 84,27 84,67 85,06 85,46 85,85 86,25 86,64 87,04 87,43 87,83 88,22-30,00 88,22 88,62 89,01 89,40 89,80 90,19 90,59 90,98 91,37 91,77 92,16-20,00 92,16 92,55 92,95 93,34 93,73 94,12 94,52 94,91 95,30 95,69 96,09-10,00 96,09 96,48 96,87 97,26 97,65 98,04 98,44 98,83 99,22 99,61 100,00 0,00 100,00 100,39 100,78 101,17 101,56 101,95 102,34 102,73 103,12 103,51 103,90 10,00 103,90 104,29 104,68 105,07 105,46 105,85 106,24 106,63 107,02 107,40 107,79 20,00 107,79 108,18 108,57 108,96 109,35 109,73 110,12 110,51 110,90 111,29 111,67 30,00 111,67 112,06 112,45 112,83 113,22 113,61 114,00 114,38 114,77 115,15 115,54 40,00 115,54 115,93 116,31 116,70 117,08 117,47 117,86 118,24 118,63 119,01 119,40 50,00 119,40 119,78 120,17 120,55 120,94 121,32 121,71 122,09 122,47 122,86 123,24 60,00 123,24 123,63 124,01 124,39 124,78 125,16 125,54 125,93 126,31 126,69 127,08 70,00 127,08 127,46 127,84 128,22 128,61 128,99 129,37 129,75 130,13 130,52 130,90 80,00 130,90 131,28 131,66 132,04 132,42 132,80 133,18 133,57 133,95 134,33 134,71 90,00 134,71 135,09 135,47 135,85 136,23 136,61 136,99 137,37 137,75 138,13 138,51 100,00 138,51 138,88 139,26 139,64 140,02 140,40 140,78 141,16 141,54 141,91 142,29 110,00 142,29 142,67 143,05 143,43 143,80 144,18 144,56 144,94 145,31 145,69 146,07 120,00 146,07 146,44 146,82 147,20 147,57 147,95 148,33 148,70 149,08 149,46 149,83 21 / 27

130,00 149,83 150,21 150,58 150,96 151,33 151,71 152,08 152,46 152,83 153,21 153,58 140,00 153,58 153,96 154,33 154,71 155,08 155,46 155,83 156,20 156,58 156,95 157,33 150,00 157,33 157,70 158,07 158,45 158,82 159,19 159,56 159,94 160,31 160,68 161,05 160,00 161,05 161,43 161,80 162,17 162,54 162,91 163,29 163,66 164,03 164,40 164,77 170,00 164,77 165,14 165,51 165,89 166,26 166,63 167,00 167,37 167,74 168,11 168,48 180,00 168,48 168,85 169,22 169,59 169,96 170,33 170,70 171,07 171,43 171,80 172,17 190,00 172,17 172,54 172,91 173,28 173,65 174,02 174,38 174,75 175,12 175,49 175,86 200,00 175,86 176,22 176,59 176,96 177,33 177,69 178,06 178,43 178,79 179,16 179,53 210,00 179,53 179,89 180,26 180,63 180,99 181,36 181,72 182,09 182,46 182,82 183,19 220,00 183,19 183,55 183,92 184,28 184,65 185,01 185,38 185,74 186,11 186,47 186,84 230,00 186,84 187,20 187,56 187,93 188,29 188,66 189,02 189,38 189,75 190,11 190,47 240,00 190,47 190,84 191,20 191,56 191,92 192,29 192,65 193,01 193,37 193,74 194,10 250,00 194,10 194,46 194,82 195,18 195,55 195,91 196,27 196,63 196,99 197,35 197,71 260,00 197,71 198,07 198,43 198,79 199,15 199,51 199,87 200,23 200,59 200,95 201,31 270,00 201,31 201,67 202,03 202,39 202,75 203,11 203,47 203,83 204,19 204,55 204,90 280,00 204,90 205,26 205,62 205,98 206,34 206,70 207,05 207,41 207,77 208,13 208,48 290,00 208,48 208,84 209,20 209,56 209,91 210,27 210,63 210,98 211,34 211,70 212,05 300,00 212,05 212,41 212,76 213,12 213,48 213,83 214,19 214,54 214,90 215,25 215,61 310,00 215,61 215,96 216,32 216,67 217,03 217,38 217,74 218,09 218,44 218,80 219,15 320,00 219,15 219,51 219,86 220,21 220,57 220,92 221,27 221,63 221,98 222,33 222,68 330,00 222,68 223,04 223,39 223,74 224,09 224,45 224,80 225,15 225,50 225,85 226,21 340,00 226,21 226,56 226,91 227,26 227,61 227,96 228,31 228,66 229,02 229,37 229,72 350,00 229,72 230,07 230,42 230,77 231,12 231,47 231,82 232,17 232,52 232,87 233,21 360,00 233,21 233,56 233,91 234,26 234,61 234,96 235,31 235,66 236,00 236,35 236,70 370,00 236,70 237,05 237,40 237,74 238,09 238,44 238,79 239,13 239,48 239,83 240,18 380,00 240,18 240,52 240,87 241,22 241,56 241,91 242,26 242,60 242,95 243,29 243,64 390,00 243,64 243,99 244,33 244,68 245,02 245,37 245,71 246,06 246,40 246,75 247,09 400,00 247,09 247,44 247,78 248,13 248,47 248,81 249,16 249,50 249,85 250,19 250,53 410,00 250,53 250,88 251,22 251,56 251,91 252,25 252,59 252,93 253,28 253,62 253,96 420,00 253,96 254,30 254,65 254,99 255,33 255,67 256,01 256,35 256,70 257,04 257,38 430,00 257,38 257,72 258,06 258,40 258,74 259,08 259,42 259,76 260,10 260,44 260,78 440,00 260,78 261,12 261,46 261,80 262,14 262,48 262,82 263,16 263,50 263,84 264,18 450,00 264,18 264,52 264,86 265,20 265,53 265,87 266,21 266,55 266,89 267,22 267,56 460,00 267,56 267,90 268,24 268,57 268,91 269,25 269,59 269,92 270,26 270,60 270,93 470,00 270,93 271,27 271,61 271,94 272,28 272,61 272,95 273,29 273,62 273,96 274,29 480,00 274,29 274,63 274,96 275,30 275,63 275,97 276,30 276,64 276,97 277,31 277,64 490,00 277,64 277,98 278,31 278,64 278,98 279,31 279,64 279,98 280,31 280,64 280,98 500,00 280,98 281,31 281,64 281,98 282,31 282,64 282,97 283,31 283,64 283,97 284,30 510,00 284,30 284,63 284,97 285,30 285,63 285,96 286,29 286,62 286,95 287,29 287,62 22 / 27

520,00 287,62 287,95 288,28 288,61 288,94 289,27 289,60 289,93 290,26 290,59 290,92 530,00 290,92 291,25 291,58 291,91 292,24 292,56 292,89 293,22 293,55 293,88 294,21 540,00 294,21 294,54 294,86 295,19 295,52 295,85 296,18 296,50 296,83 297,16 297,49 550,00 297,49 297,81 298,14 298,47 298,80 299,12 299,45 299,78 300,10 300,43 300,75 560,00 300,75 301,08 301,41 301,73 302,06 302,38 302,71 303,03 303,36 303,69 304,01 570,00 304,01 304,34 304,66 304,98 305,31 305,63 305,96 306,28 306,61 306,93 307,25 580,00 307,25 307,58 307,90 308,23 308,55 308,87 309,20 309,52 309,84 310,16 310,49 590,00 310,49 310,81 311,13 311,45 311,78 312,10 312,42 312,74 313,06 313,39 313,71 600,00 313,71 314,03 314,35 314,67 314,99 315,31 315,64 315,96 316,28 316,60 316,92 610,00 316,92 317,24 317,56 317,88 318,20 318,52 318,84 319,16 319,48 319,80 320,12 620,00 320,12 320,43 320,75 321,07 321,39 321,71 322,03 322,35 322,67 322,98 323,30 630,00 323,30 323,62 323,94 324,26 324,57 324,89 325,21 325,53 325,84 326,16 326,48 640,00 326,48 326,79 327,11 327,43 327,74 328,06 328,38 328,69 329,01 329,32 329,64 650,00 329,64 329,96 330,27 330,59 330,90 331,22 331,53 331,85 332,16 332,48 332,79 660,00 332,79 333,11 333,42 333,74 334,05 334,36 334,68 334,99 335,31 335,62 335,93 670,00 335,93 336,25 336,56 336,87 337,18 337,50 337,81 338,12 338,44 338,75 339,06 680,00 339,06 339,37 339,69 340,00 340,31 340,62 340,93 341,24 341,56 341,87 342,18 690,00 342,18 342,49 342,80 343,11 343,42 343,73 344,04 344,35 344,66 344,97 345,28 700,00 345,28 345,59 345,90 346,21 346,52 346,83 347,14 347,45 347,76 348,07 348,38 710,00 348,38 348,69 348,99 349,30 349,61 349,92 350,23 350,54 350,84 351,15 351,46 720,00 351,46 351,77 352,08 352,38 352,69 353,00 353,30 353,61 353,92 354,22 354,53 730,00 354,53 354,84 355,14 355,45 355,76 356,06 356,37 356,67 356,98 357,28 357,59 740,00 357,59 357,90 358,20 358,51 358,81 359,12 359,42 359,72 360,03 360,33 360,64 750,00 360,64 360,94 361,25 361,55 361,85 362,16 362,46 362,76 363,07 363,37 363,67 760,00 363,67 363,98 364,28 364,58 364,89 365,19 365,49 365,79 366,10 366,40 366,70 770,00 366,70 367,00 367,30 367,60 367,91 368,21 368,51 368,81 369,11 369,41 369,71 780,00 369,71 370,01 370,31 370,61 370,91 371,21 371,51 371,81 372,11 372,41 372,71 790,00 372,71 373,01 373,31 373,61 373,91 374,21 374,51 374,81 375,11 375,41 375,70 800,00 375,70 376,00 376,30 376,60 376,90 377,19 377,49 377,79 378,09 378,39 378,68 810,00 378,68 378,98 379,28 379,57 379,87 380,17 380,46 380,76 381,06 381,35 381,65 820,00 381,65 381,95 382,24 382,54 382,83 383,13 383,42 383,72 384,01 384,31 384,60 830,00 384,60 384,90 385,19 385,49 385,78 386,08 386,37 386,67 386,96 387,25 387,55 840,00 387,55 387,84 388,14 388,43 388,72 389,02 389,31 389,60 389,90 390,19 390,48 850,00 390,48 23 / 27

7.3. Links http://de.wikipedia.org/wiki/pt100 www.pt100.de 7.4. Manufacturer of Pt and Ni based resistive temperature sensors Heraeus Sensor Nite HYGROSENS Instruments GmbH IST Jumo Rössel www.heraeus-sensor-technology.de www.hygrosens.com www.ist-ag.com www.jumo.net/pt100 www.roesselgruppe.de 24 / 27

8 Further documents table 6 Further documents Document Functional Description Datasheet File Name _FunctionalDescription_Rev_x_yz.pdf Datasheet_Rev_a_bc.pdf Visit ZMD s website www.zmd.biz or contact your nearest sales office for the latest version of these documents. 25 / 27

9 Glossary table 7 Glossary Term RTD PTC PGA ADC DSP DAC PWM I 2 C SPI ZACwire THT SMT Description Resistance Temperature Detection Positive Temperature Coefficient Programmable Gain Amplifier Analog-to-Digital-Converter Digital Signal Processor Digital-to-Analog-Converter Pulse Width Modulation Serial Inter-IC-bus (PHILIPS) Serial Peripheral Interface (MOTOROLA) Bi-directional, proprietary serial one-wire-interface of ZMD Through-Hole-Technology Surface-Mounting-Technology 26 / 27

10 Document Revision History table 8 Revision Revision Date Description 0.90 February 15 th, 2009 Update after review 0.46 February 01 st, 2009 First release after format update Sales Offices and Further Information ZMD AG Grenzstrasse 28 01109 Dresden Germany Phone +49 (0)351.8822.7.772 Fax +49(0)351.8822.87.772 sales@zmdi.com ZMD America, Inc. 201 Old Country Road Suite 204 Melville, NY 11747 USA Phone +01 (631) 549-2666 Fax +01 (631) 549-2882 sales@zmdi.com ZMD Japan 2 nd Floor, Shinbashi Tokyu Bldg. 4-21-3, Shinbashi, Minato-ku Tokyo, 105-0004 Japan Phone +81.3.6895.7410 Fax +81.3.6895.7301 sales@zmdi.com www.zmdi.com ZMD Far East 3F, No.,51, Sec. 2, Keelung Road 11052 Taipei Taiwan Phone +886.3.563.1388 Fax +886.3.563.6385 sales@zmdi.com 27 / 27