ECE Elective 1 (2425_Term 1) Instrumentation (Temperature Sensors) PDF

ECE Elective 1 (2425_Term 1) BETELXT-NS-T-3A-T Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  TEMPERATURE AND HEAT Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  THERMODYNAMICS Instrumentation (2425_Term 1) BETEL...

ECE Elective 1 (2425_Term 1) BETELXT-NS-T-3A-T Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  TEMPERATURE AND HEAT Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  THERMODYNAMICS Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  HEAT Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  HEAT describes the transfer of thermal energy between molecules within a system and is measured in Joules. Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  HEAT describes the transfer of thermal energy between molecules within a system and is measured in Joules. Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  HEAT describes the transfer of thermal energy between molecules within a system and is measured in Joules. Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  TEMPERATURE Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  TEMPERATURE describes the average kinetic energy of molecules within a material or system and is measured in Celsius (°C), Kelvin(K), Fahrenheit (°F), or Rankine (R). Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  TEMPERATURE describes the average kinetic energy of molecules within a material or system and is measured in Celsius (°C), Kelvin(K), Fahrenheit (°F), or Rankine (R). Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Kelvin Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  25°C Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  25°C To Fahrenheit Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  25°C To Kelvin Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  25°C To Rankine Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  274.15K To Rankine Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  274.15K To Fahrenheit Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  274.15K To Celsius Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  HEAT Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  HEAT Methods of Heat Transfer Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Methods of Heat Transfer CONDUCTION occurs between objects that are touching each other. Collisions between small particles allow fast moving, or vibrating, particles to give some of their microscopic kinetic energy to slower particles. Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Methods of Heat Transfer CONDUCTION occurs between objects that are touching each other. Collisions between small particles allow fast moving, or vibrating, particles to give some of their microscopic kinetic energy to slower particles. Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Methods of Heat Transfer CONVECTION is heat transfer caused by moving fluids. In a fluid, particles can mix together, move faster, and spread out, thus distributing their thermal energy. Warm air coming from a heating vent to flow around a cool room is an example of convection. Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Methods of Heat Transfer CONVECTION is heat transfer caused by moving fluids. In a fluid, particles can mix together, move faster, and spread out, thus distributing their thermal energy. Warm air coming from a heating vent to flow around a cool room is an example of convection. Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Methods of Heat Transfer RADIATION occurs without the movement of matter. Thermal radiation is made of electromagnetic waves given off by moving particles. These waves can also be absorbed by materials. Microwave ovens work by radiation and the entire surface of the Earth is heated by the sun's solar radiation. Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Methods of Heat Transfer RADIATION occurs without the movement of matter. Thermal radiation is made of electromagnetic waves given off by moving particles. These waves can also be absorbed by materials. Microwave ovens work by radiation and the entire surface of the Earth is heated by the sun's solar radiation. Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  TEMPERATURE SENSORS Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  TEMPERATURE SENSORS detect a change in a physical parameter such as resistance or output voltage that corresponds to a temperature change. Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  2 BASIC TYPES OF TEMPERATURE SENSING Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  2 BASIC TYPES OF TEMPERATURE SENSING 1. Contact 2. Non-contact Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  CONTACT temperature sensing requires the sensor to be in direct physical contact with the media or object being sensed. It can be used to monitor the temperature of solids, liquids or gases over an extremely wide temperature range. Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  NON-CONTACT measurement interprets the radiant energy of a heat source in the form of energy emitted in the infrared portion of the electromagnetic spectrum. This method can be used to monitor non-reflective solids and liquids but is not effective with gases due to their natural transparency. Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  TEMPERATURE SENSORS FAMILY Temperature Sensors Electro-Mechanical Electronic Resistive Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Electro-Mechanical BI-METAL THERMOSTATS are exactly what the name implies: two different metals bonded together under heat and pressure to form a single strip of material. By employing the different expansion rates of the two materials, thermal energy can be converted into electro-mechanical motion. Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Electro-Mechanical BI-METAL THERMOSTATS are exactly what the name implies: two different metals bonded together under heat and pressure to form a single strip of material. By employing the different expansion rates of the two materials, thermal energy can be converted into electro-mechanical motion. Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Electro-Mechanical BULB AND CAPILLARY THERMOSTATS make use of the capillary action of expanding or contracting fluid to make or break a set of electrical contacts. Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Electro-Mechanical BULB AND CAPILLARY THERMOSTATS make use of the capillary action of expanding or contracting fluid to make or break a set of electrical contacts. Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Electronic SILICON SENSORS make use of the bulk electrical resistance properties of semiconductor materials, rather than the junction of two differently doped areas. Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Electronic SILICON SENSORS make use of the bulk electrical resistance properties of semiconductor materials, rather than the junction of two differently doped areas. Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Electronic INFRARED (IR) PYROMETRY measure the infrared energy emitted from an object in the 4–20 micron wavelength and convert the reading to a voltage Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Electronic INFRARED (IR) PYROMETRY measure the infrared energy emitted from an object in the 4–20 micron wavelength and convert the reading to a voltage Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Electronic THERMOCOUPLES are formed when two electrical conductors of dissimilar metals or alloys are joined at one end of a circuit. Typically, they are built around bare conductors and insulated by ceramic powder or formed ceramic. Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Electronic THERMOCOUPLES are formed when two electrical conductors of dissimilar metals or alloys are joined at one end of a circuit. Typically, they are built around bare conductors and insulated by ceramic powder or formed ceramic. Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Resistive Devices THERMISTORS (or thermally sensitive resistors) are devices that change their electrical resistance in relation to their temperature. They typically consist of a combination of two or three metal oxides that are sintered in a ceramic base material and have lead wires soldered to a semiconductor wafer or chip, which are covered with epoxy or glass. Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Resistive Devices THERMISTORS (or thermally sensitive resistors) are devices that change their electrical resistance in relation to their temperature. They typically consist of a combination of two or three metal oxides that are sintered in a ceramic base material and have lead wires soldered to a semiconductor wafer or chip, which are covered with epoxy or glass. Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Resistive Devices THERMISTORS Thermistors Positive Negative Temperature Temperature Coefficient (PTC) Coefficient (NTC) Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Resistive Devices THERMISTORS Positive Temperature Coefficient (PTC) TEMPERATURE Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Resistive Devices THERMISTORS Positive Temperature Coefficient (PTC) TEMPERATURE RESISTANCE Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Resistive Devices THERMISTORS Negative Temperature Coefficient (NTC) TEMPERATURE Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Resistive Devices THERMISTORS Negative Temperature Coefficient (NTC) TEMPERATURE RESISTANCE Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Electronic RESISTIVE TEMPERATURE DEVICES The metal sensing element is an electrical resistor that changes resistance with temperature. The element usually contains a coil of wire or conductive film with conductors etched or cut into it. It is usually housed in ceramic and sealed with ceramic cement or glass. Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Electronic RESISTIVE TEMPERATURE DEVICES The metal sensing element is an electrical resistor that changes resistance with temperature. The element usually contains a coil of wire or conductive film with conductors etched or cut into it. It is usually housed in ceramic and sealed with ceramic cement or glass. Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  SELECTING AND SPECIFYING TEMPERATURE SENSORS Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  THERMISTORS provide high resolution, have the widest range of applications, are the most sensitive, and are low cost, but are nonlinear and have limited temperature range. SELECTING AND SPECIFYING Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T TEMPERATURE SENSORS  THERMISTORS provide high resolution, have the widest range of applications, are the most sensitive, and are low cost, but are nonlinear and have limited temperature range. SELECTING AND SPECIFYING Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T TEMPERATURE SENSORS  THERMISTORS provide high resolution, have the widest range of applications, are the most sensitive, and are low cost, but are nonlinear and have limited temperature range. SELECTING AND SPECIFYING Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T TEMPERATURE SENSORS  THERMOCOUPLES have the highest temperature region and are durable for high-vibration and high-shock applications, but require special extension wire. SELECTING AND SPECIFYING Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T TEMPERATURE SENSORS  THERMOCOUPLES have the highest temperature region and are durable for high-vibration and high-shock applications, but require special extension wire. SELECTING AND SPECIFYING Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T TEMPERATURE SENSORS  THERMOCOUPLES have the highest temperature region and are durable for high-vibration and high-shock applications, but require special extension wire. SELECTING AND SPECIFYING Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T TEMPERATURE SENSORS  RESISTIVE TEMPERATURE DEVICES are nearly linear and are highly accurate and stable, but they are large and expensive. SELECTING AND SPECIFYING Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T TEMPERATURE SENSORS  RESISTIVE TEMPERATURE DEVICES are nearly linear and are highly accurate and stable, but they are large and expensive. SELECTING AND SPECIFYING Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T TEMPERATURE SENSORS  RESISTIVE TEMPERATURE DEVICES are nearly linear and are highly accurate and stable, but they are large and expensive. SELECTING AND SPECIFYING Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T TEMPERATURE SENSORS  SILICON TYPES are low cost and nearly linear, but have a limited temperature range. SELECTING AND SPECIFYING Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T TEMPERATURE SENSORS  SILICON TYPES are low cost and nearly linear, but have a limited temperature range. SELECTING AND SPECIFYING Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T TEMPERATURE SENSORS  SILICON TYPES are low cost and nearly linear, but have a limited temperature range. SELECTING AND SPECIFYING Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T TEMPERATURE SENSORS  Accuracy is the sensor’s ability to measure the temperature’s true value over a temperature range. SELECTING AND SPECIFYING Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T TEMPERATURE SENSORS  Does the application require contact or non-contact sensing? SELECTING AND SPECIFYING Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T TEMPERATURE SENSORS  What temperature range is the sensor required to control or monitor? SELECTING AND SPECIFYING Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T TEMPERATURE SENSORS  What temperature range is the sensor required to control or monitor? Cryogenic Temperature Cases SELECTING AND SPECIFYING Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T TEMPERATURE SENSORS  What temperature range is the sensor required to control or monitor? Non Contact Extreme Temperatures below –18°C or above 538°C SELECTING AND SPECIFYING Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T TEMPERATURE SENSORS  What is the rate of temperature change of the application? SELECTING AND SPECIFYING Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T TEMPERATURE SENSORS  How tightly do you need to control or monitor the temperature? SELECTING AND SPECIFYING Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T TEMPERATURE SENSORS  How important is total system cost in the selection of the sensor? SELECTING AND SPECIFYING Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T TEMPERATURE SENSORS  ADVANTAGES AND DISADVANTAGES Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Electro-Mechanical BI-METAL THERMOSTATS Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Electro-Mechanical BI-METAL THERMOSTATS Direct interface with application for fast response No additional circuitry/components required Available in both hermetic and non-hermetically sealed designs High current carrying capacity Wide operating temperature range Application/market-based pricing NASA qualified high reliability and military versions available Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Advantages  Electro-Mechanical BI-METAL THERMOSTATS Less accurate than most electronic-based systems Larger size than electronic-based systems Creepage-type device cannot interface with electronic components Can fail “closed” at end of life Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Disadvantages  Electro-Mechanical BULB AND CAPILLARY THERMOSTATS Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Electro-Mechanical BULB AND CAPILLARY THERMOSTATS Control can be located at a significant distance from application being sensed Built-in overtemperature systems available Broad operating temperature range High current carrying capability Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Advantages  Electro-Mechanical BI-METAL THERMOSTATS Large size Relatively expensive Limited number of potential applications Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Disadvantages  Electronic Sensors SILICON SENSORS Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Electronic Sensors SILICON SENSORS Less expensive than RTDs More linear than thermistors Easier to use than RTDs or thermocouples due to higher output IC types feature on-chip signal conditioning Many IC types include communication protocols with bus-type data acquisition systems Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Advantages  Electronic Sensors SILICON SENSORS Not as linear as RTDs Less accurate than other electronic-based systems More expensive than thermistors or thermocouples Limited temperature range Slower thermal response than other electronic-based systems Typically larger than RTDs and thermistors Require larger package sizes for immersion Additional components/circuitry required to control application loads Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Disadvantages  Electronic Sensors INFRARED (IR) PYROMETRY Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Electronic Sensors INFRARED (IR) PYROMETRY Allows for non-contact measurement of moving objects or hazardous materials Can be used in conjunction with fiber optics for remote sensing Typical temperature range –18 to +538°C (0 to 1000°F) Accuracy to ±1% Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Advantages  Electronic Sensors INFRARED (IR) PYROMETRY Accuracy can be affected by surface finish Field of view must be matched to target size Ambient temperature can affect readings Wavelength filter must be matched to the applicatioN Higher cost ($200+) can be even higher if control circuitry is Required Calibration can be difficult and costly Additional components/circuitry required to control application loads Dust, gas, or other vapors in the environment can effect the accuracy of the system Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Disadvantages  Electronic Sensors THERMOCOUPLES Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Electronic Sensors THERMOCOUPLES Small size provides rapid temperature response Relatively inexpensive Wide temperature range More durable than RTDs for use in high-vibration and high-shock applications ANSI established calibration types Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Advantages  Electronic Sensors THERMOCOUPLES Must be protected from corrosive environments Smaller gage wire sizes are less stable and have a shorter operating life Use of plated-copper instrumentation wire results in errors when ambient temperatures change Special extension wires are required Reference junction compensation is required Less stable than RTDs in moderate or high temperatures Should be tested to verify performance under controlled conditions for critical applications Additional components/circuitry required to control application loads Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Disadvantages  Resistive Sensors THERMISTORS Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Resistive Sensors THERMISTORS Low component cost Fast thermal response Large change in resistance vs. temperature for more resolution Extremely small size means faster reaction to change in temperature and ability to use in variety of assemblies Linearized resistance types available High resistance values so no lead wire compensation necessary Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Advantages  Resistive Sensors THERMISTORS Limited temperature range Lower temperature exposures than RTDs or thermocouples No established resistance standards Self heating can affect accuracy Non-linear resistance change requires additional components for accurate interpretation Increased component count decreases system reliability Additional components/circuitry required to control application loads Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Disadvantages  Resistive Sensors RESISTANCE TEMPERATURE DETECTOR Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T  Resistive Sensors RESISTANCE TEMPERATURE DETECTOR Very accurate and repeatable Wide temperature range –200 to +650°C (–328 to +1202°F) depending on type Extremely stable over time: >0.1°C/year drift Larger voltage output than thermocouples Excellent resistance linearity Resistance can be determined in the laboratory and will not vary significantly over time Area or point sensing Low variation for better interchangeability Can use standard instrumentation cable to connect to control equipment Established industry accepted resistance curves Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Advantages  Resistive Sensors RESISTANCE TEMPERATURE DETECTOR Higher cost than thermistors or thermocouples Self heating of the RTD can affect overall system accuracy Larger size than thermistors or thermocouples Not as durable as thermocouples in high-vibration and high-shock environments Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T Disadvantages Instrumentation (2425_Term 1) BETELXT-NS-T-3A-T ECE Elective 3 (2425_Term 1) BETELXT-NS-T-3A-T THANK YOU!