Newnes Sensor Technology Handbook 2005 Yyepg Lotb Part 15 ppt

Chapter 20 550 Canadian Standards Association (CSA): http://www.csa.ca Not-for-profit membership-based association serving business, industry, gov- ernment, and consumers in Canada and around the world. Develops standards for enhancing public safety and health, advancing the quality of life, helping to preserve the environment, and facilitating trade. Instrumentation, Systems, and Automation Society (ISA): http://www.isa.org Helps advance the theory, design, manufacture, and use of sensors, instru- ments, computers, and systems for measurement and control in a variety of applications. International Electrotechnical Commission (IEC): http://www.iec.ch Prepares and publishes international standards for all electrical, electronic, and related technologies. International Organization for Standardization (ISO): http://www.iso.ch/iso/en/ISOOnline.openerpage A network of national standards institutes from 146 countries working in part- nership with international organizations, governments, industry, business and consumer representatives. Japanese Standards Association (JSA): http://www.jsa.or.jp/default_english.asp Objective is “to educate the public regarding the standardization and unifica- tion of industrial standards, and thereby to contribute to the improvement of technology and the enhancement of production efficiency.” National Institute of Standards and Technology (NIST): http://www.nist.gov Founded in 1901, NIST is a non-regulatory federal agency within the U.S. Com- merce Department’s Technology Administration. Its mission is to develop and promote measurement, standards, and technology to enhance productivity, facili- tate trade, and improve the quality of life. Note: All thermistor testing and calibration baths are measured to the “International Temperature Scale of 1990” (http://www.its-90.com) using instrumentation from Hart Scientific (http://www.hartscientific.com/). Temperature Sensing 551 Industry Organizations American Society for Quality (ASQ): http://www.asq.org/ Purpose is to improve workplace and communities by advancing learning, quality improvement, and knowledge exchange. Advises the U.S. Congress, government agencies, state legislatures, and other groups and individuals on quality-related topics. International Measurement Confederation (IMEKO): http://www.mit.tut.fi/imeko/ Non-governmental federation of 36 member organizations. Promotes inter- national interchange of scientific and technical information in the field of measurement and instrumentation and the international cooperation among scientists and engineers from research and industry. National Conference of Standards Laboratories International (NCSL International): http://www.ncsli.org/ A professional association for individuals involved in all aspects of measure- ment science. Underwriter’s Laboratories (UL): http://www.ul.com An independent, not-for-profit product-safety testing and certification organization. Applicable Standards and Specifications Electro-mechanical Devices MIL-PRF-24236 Switches, (Bi-metallic and Metallic), General Specification for Issued by: Defense Supply Center (DOD) ANSI Z21.21 Thermostats, gas appliance Issued by: American National Standards Institute UL873 Standard for Temperature Indicating and Regulating Equipment Issued by: Underwriters Laboratory CAN/CSA 22.2 No. 24-1993 Temperature Indicating and Regulating Equipment Issued by: Canadian Standards Association Chapter 20 552 Thermistors MIL-PRF-23648 Resistor, Thermal (Thermistor) Insulated, General Specification for Issued by: Defense Supply Center (DOD) ANSI/EIA 337 Glass Coated Thermistor Beads and Thermistor Beads in Glass Probes and Glass Rods (NTC) General Specification for Issued by: American National Standards Institute ANSI/EIA 275 Thermistor Definitions and Test Methods Issued by: American National Standards Institute Thermocouples ANSI MC96.1 Thermocouples, General Specification for Issued by: Instrument Society of America MIL-T-24388 Resistive Temperature Devices (RTDs) and Thermocouples for Shipboard Use, General Specification for Issued by: U.S. Naval Sea Systems Command RTDs IEC-751 Resistance Standards for Resistive Temperature Devices (RTDs) Issued by: International Electrotechnical Commission JIS C 1604 Resistance Standards for Resistive Temperature Devices (RTDs) Issued by: Japanese Standards Association DIN 43760 Resistance Standards for Nickel Resistive Temperature Devices (RTDs) Issued by: Deutsches Institut fur Normung BS 1904 Resistance Standards for Resistive Temperature Devices (Same as IEC 751) Issued by: British Standards Association Temperature Sensing 553 SAMA RC21-4-1966 Resistance Standards for Resistive Temperature Devices (RTDs) Issued by: Scientific Apparatus Makers Association MIL-T-24388 Resistive Temperature Devices (RTDs) and Thermocouples for Shipboard Use, General Specification for Issued by: U.S. Naval Sea Systems Command 20.4 Interfacing and Design Information The most important consideration with any type of sensing technology is sensor location. In a control application, where the rate of temperature change is fairly slow, the sen- sor should be located as close to the heat source as possible. In this way, the thermal lag is minimal. The heat source will cycle more frequently; however, it will eliminate potential undershoot or overshoot of the application. When the rate of temperature change is rapid due to the thermal conductivity of the material or because of frequent changes in the mass being heated, the sensor should be located as close to the material as possible. This will cause the heat source cycle to be longer and increase fluctuations of the workload. With an electronic-based system, these fluctuations can be minimized with a PID controller. In all circumstances, the distance between the heat source, sensor and mass to be heated should be as short as possible. This will minimize thermal lag, workload tem- perature fluctuations and power usage. Bi-metallic and Bulb and Capillary Thermostats Electro-mechanical sensors are typically the simplest components to interface with their applications. Since they are capable of either opening or closing with increasing temperature, they are capable of interrupting a power circuit to control or shut down a circuit or of closing a circuit to sound an alarm, turn on a fan, etc. In most circumstances, thermostats are connected to one leg of the power source. When the application temperature is reached, the device will function to either make or break the circuit. Chapter 20 554 When the electrical load required by the application exceeds the capabilities of the thermostat, the thermostat can be used in conjunction with a relay, contactor or some other type of power handling component. Resistance and Accuracy Sensor accuracy is a function of production tolerance and any additional calibration that the sensor may get. Calibration can improve the accuracy of an RTD by 10 times over production tolerance. The accuracy values in Table 20.4.1 apply to production tolerance tight trim RTDs with ice point tolerances of R 0 ±0.1%. The thin film values in Table 20.4.2 are for tight trim platinum RTDs. Both thin film and wire-wound tight trim RTDs with 0.00385 alpha values meet IEC 751 Class B. In qualifying volumes, RTDs can be laser trimmed for tight resistance interchange- ability at any temperature between 0°C and 150°C or to an ice point resistance other than 100 Ω or 1000 Ω. Laser trimming also allows matching the resistance of RTDs with different alpha values at a target temperature. Table 20.4.1: Accuracy* vs. temperature. Ice Point, Alpha Value 1000Ω 0.00375 100Ω 0.00385 100Ω 0.003902 Temperature °C ±∆Resistance (Ω) –200 5.1 0.5 0.5 –100 2.4 0.3 0.3 0 1.0 0.1 0.1 100 2.2 0.2 0.2 200 4.3 0.4 0.4 300 6.2 0.6 0.6 400 8.3 0.8 0.8 500 9.6 1.0 1.0 600 10.4 1.2 1.2 Temperature °C ±∆Temperature (°C) –200 1.2 1.2 1.2 –100 0.6 0.6 0.6 0 0.3 0.3 0.3 100 0.6 0.6 0.6 200 1.2 1.2 1.2 300 1.8 1.8 1.8 400 2.5 2.5 2.5 500 3.0 3.0 3.0 600 3.3 3.6 3.6 * Figures are for production tolerance tight trim RTDs. Temperature Sensing 555 Table 20.4.2: Platinum RTD resistance vs. temperature. Ice Point, Alpha Value & RTD Type 1000Ω 0.00375 Pt Thin Film 100Ω 0.00385 Pt Thin Film 100Ω 0.00385 Pt WW 100Ω 0.003902 Pt WW Temperature °C Resistance (Ω) –200 199.49 18.10 18.10 19.76 –180 284.87 26.81 26.81 28.01 –160 368.57 35.35 35.35 36.17 –140 450.83 43.75 43.75 44.27 –120 531.83 52.04 52.04 52.31 –100 611.76 60.21 60.21 60.31 –80 690.78 68.30 68.30 68.27 –60 769.01 76.32 76.32 76.22 –40 846.58 84.27 84.27 84.15 –20 923.55 92.16 92.16 92.08 0 1000.00 100.00 100.00 100.00 20 1075.96 107.79 107.79 107.92 40 1151.44 115.54 115.54 115.84 60 1226.44 123.24 123.24 123.76 80 1300.96 130.89 130.89 131.69 100 1375.00 138.50 138.50 139.61 120 1448.56 146.06 146.06 147.53 140 1521.63 153.57 153.57 155.45 160 1594.22 161.04 161.04 163.37 180 1666.33 168.46 168.46 171.29 200 1737.96 175.83 175.83 179.21 220 1809.11 183.16 183.16 187.14 240 1879.78 190.43 190.43 195.06 260 1949.96 197.67 197.67 202.98 280 2019.67 204.85 204.85 210.90 300 2088.89 211.99 211.99 218.82 320 2157.63 219.08 219.08 226.74 340 2225.89 226.12 226.12 234.66 360 2293.66 233.12 233.12 242.59 380 2360.96 240.07 240.07 250.51 400 2427.78 246.98 246.98 258.43 420 2494.11 253.83 253.83 266.35 440 2559.96 260.65 260.65 274.27 460 2625.33 267.41 267.41 282.19 480 2690.22 274.13 274.13 290.11 500 2754.63 280.80 280.80 298.04 520 2818.55 287.42 287.42 305.96 540 2881.99 294.00 294.00 313.88 560 2944.96 300.53 300.53 321.80 Chapter 20 556 Ice Point, Alpha Value & RTD Type 1000Ω 0.00375 Pt Thin Film 100Ω 0.00385 Pt Thin Film 100Ω 0.00385 Pt WW 100Ω 0.003902 Pt WW Temperature °C Resistance (Ω) 580 3007.44 307.01 600 3069.44 313.44 620 3130.96 319.83 640 3191.99 326.18 660 3252.55 332.47 680 3312.62 338.72 700 3372.21 344.92 720 3431.32 351.08 740 3489.95 357.18 750 3519.09 360.22 Temperature Circuits Two-wire circuit: A Wheatstone bridge is the most common approach for measuring an RTD. As R T increases or decreases with temperature, V out also increases or decreas- es. Use an op-amp to observe V out . Lead wire resistance, L 1 and L 2 directly adds to the RTD leg of the bridge. (See Figure 21.4.1.) Figure 20.4.1: Two-wire temperature circuit. Three-wire circuit: In this approach, L 1 and L 3 carry the bridge current. When the bridge is in balance, no current flows through L 2 , so no L 2 lead resistance is observed. The bridge becomes unbalanced as R T changes. Use an op-amp to observe V out and prevent current flow in L 2 . The effects of L 1 and L 3 cancel when L 1 = L 3 since they are in separate arms of the bridge. (See Figure 20.4.2.) Table 20.4.2: Platinum RTD resistance vs. temperature (continued). Temperature Sensing 557 Figure 20.4.2: Three-wire temperature circuit. Four-wire circuit: A four-wire approach uses a constant current source to cancel lead wire effects even when L 1 ≠ L 4 . Use an op-amp to observe V out and prevent current flow in L 2 and L 3 . (See Figure 20.4.3.) Figure 20.4.3: Four-wire temperature circuit. Temperature switch. The following circuit causes an output voltage to rail whenever the temperature of the RTD rises above a fixed value T 1 . The open-collector out- put simplifies the interfacing of this circuit with additional electronics. (See Figure 20.4.4.) Chapter 20 558 Figure 20.4.4: Temperature switch circuit. Temperature switch with hysteresis. The following circuit uses positive feedback from the output to self heat the RTD enough to develop a hysteresis in the behavior of the switch. Once on, the temperature must drop low enough to offset the self heating before the switch will disable. (See Figure 20.4.5.) Figure 20.4.5: Temperature switch with hysteresis circuit. [...]... Temperature Sensor. ” Sensors 17 (2000):54-57 Measurements Science Conference (MSC): http://www.msc-conf.com/ Quelch, D “Humidity Sensors for Industrial Applications.” International Conference on Sensors and Transducers, Vol 1 Tavistock, UK: Trident Exhibitions, 2001 Scolio, Jay “Temperature Sensor: ICs Simplify Designs.” Sensors 17 (2000): 48-53 561 This page intentionally left blank CHAPTER 21 Nanotechnology-Enabled... Verlag, M Fujita, ed., 1st Ed., May 15, 2000 9 Zyvex Capabilities 10 Vo-Dinh, T., B.M Cullum, and D.L Stokes, “Nanosensors and Biochips: Frontiers in Biomolecular Diagnosis,” Sensors and Actuators B, 74 (2001) pp 2–11 11 Poncharal, P., et al., “Electrostatic Deflections and Electromechanical Resonances of Carbon Nanotubes,” Science, 283 :151 3 151 6 (1999), pp 151 3 151 6 12 Toon, J., “Weighing the Very... Modi, A., et al., “Miniaturized Gas Ionization Sensors using Carbon Nanotubes,” Nature, Vol 424, Jul 10, 2003, pp 171–174 572 Nanotechnology-Enabled Sensors: Possibilities, Realities, and Applications 15 Grimes, C.A., et al., “A Sentinel Sensor Network for Hydrogen Sensing,” Sensors/MDPI, 2003, pp 69–82 16 Kong, J., et al., “Nanotube Molecular Wires as Chemical Sensors,” Science, Vol 287, Jan 28, 2000,... consumed by the sensor itself Therefore, the hardware should be designed to allow the microprocessor to judiciously control power to the radio, sensor, and sensor signal conditioner 576 Wireless Sensor Networks: Principles and Applications Sensor Inputs Lithium thionyl chloride battery Radio frequency (RF) transceiver Sensor signal conditioning 8-bit, low power, microcontroller Flash EEPROM for sensor logging... copyright permission from Nature Publishing Group) Chemical Sensors Various nanotube-based gas sensors have been described in the past few years Modi et al have developed a miniaturized gas ionization detector based on CNTs [14] The sensor could be used for gas chromatography Titania nanotube hydrogen sensors [15] have been incorporated in a wireless sensor network to detect hydrogen concentrations in the... Bakker, A “CMOS Smart Temperature Sensors: An Overview.” Proceedings of IEEE Sensors 2002 Piscataway, NJ: IEEE, 2002 Bakker, A and Jonah H Huijsing High Accuracy CMOS Smart Temperature Sensors Boston: Kluwer Academic Publishers, 2000 Desmarais, Ron and Jim Breuer “How to Select and Use the Right Temperature Sensor. ” Sensors 18 (2001):24-36 Honeywell web site, temperature sensor information: http://content.honeywell.com/sensing/prodinfo/temperature/#technical... 21.3 Applications Few sensors today are based on pure nanoscience, and the development of nano-enabled sensors is in the early stages; yet we can already foresee some of the possible devices and applications Sensors for physical properties were the focus of some early development efforts, but nanotechnology will contribute most heavily to realizing the potential of chemical and biosensors for safety,... Nanotechnology-Enabled Sensors: Possibilities, Realities, and Applications Sharon Smith, Lockheed Martin Corporation David J Nagel, The George Washington University This article is reprinted from Sensors magazine, November 2003 Used with permission If you make or use sensors, your business will likely feel the impact of current and future developments in nanotechnology, a very promising new branch of small-scale technology. .. also been demonstrated applicable to nanocantilever sensors [18] 568 Nanotechnology-Enabled Sensors: Possibilities, Realities, and Applications Figure 21.3.3: This nano-array incorporates capacitive readout cantilevers and electronics for signal analysis (Courtesy of Thomas G Thundat, Ph.D., Oak Ridge National Laboratory, Oak Ridge, TN.) Biosensors Nanotechnology will also enable the very selective, sensitive... unmanned aerial vehicles 570 Nanotechnology-Enabled Sensors: Possibilities, Realities, and Applications Figure 21.3.6: The SnifferSTAR is a nano-enabled chemical sensor integrated into a micro unmanned aerial vehicle (Courtesy of Sandia National Laboratories, Albuquerque NM, and Lockheed Martin Corp.) And More Other areas we expect to benefit from nanotechnology-based sensors include transportation (land, . 76.32 76.22 –40 846.58 84.27 84.27 84 .15 –20 923.55 92.16 92.16 92.08 0 1000.00 100.00 100.00 100.00 20 1075.96 107.79 107.79 107.92 40 1151 .44 115. 54 115. 54 115. 84 60 1226.44 123.24 123.24 123.76 80. 130.89 131.69 100 1375.00 138.50 138.50 139.61 120 1448.56 146.06 146.06 147.53 140 152 1.63 153 .57 153 .57 155 .45 160 159 4.22 161.04 161.04 163.37 180 1666.33 168.46 168.46 171.29 200 1737.96 175.83. Temperature Sensor. ” Sensors 17 (2000):54-57. Measurements Science Conference (MSC): http://www.msc-conf.com/ Quelch, D. “Humidity Sensors for Industrial Applications.” International Conference on Sensors