ECE5320 Mechatronics Assignment#01: Literature Survey on Sensors and Actuators Topic Ammonia sensor based on Thin film polymer technologySensor OutlineReferencesReferencesIntroductionBackgroundDetection-MethodsPrinciple of sensorFigureOperationSlide 11Slide 12Advantages over other sensorsAdvantagesSlide 15Sensor SpecificationsApplicationsSome other Ammonia sensorsOther ammonia sensorsOther ammonia sensorsWhere to buyConclusionECE5320 MechatronicsAssignment#01: Literature Survey on Sensors and Actuators Assignment#01: Literature Survey on Sensors and Actuators TopicAmmonia sensor based on Thin film polymer technologyPrepared by:Bhanu Prakash GollaDept. of Electrical and Computer Engineering Utah State UniversityEmail:[email protected] F: (435)797-3054 (ECE Dept.)3/9/200701/13/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-2Sensor Outline –Reference list–Introduction–Background–Basic working principle illustrated–Major specifications–Advantages –Application–Where to Buy–Conclusion01/13/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-3References •http://archives.sensorsmag.com/articles/0502/73/•http://www.springerlink.com/content/ru080123256ht2r3/•http://www.vaisala.com/•http://www.sensorsmag.com/sensors/article/articleDetail.jsp?id=186851•www.howstuffworks.com•http://ieeexplore.ieee.org01/13/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-4References•http://en.wikipedia.org/wiki/Ammonia•http://www.ufcw.org/your_industry/manufacturing/safety_health_news_and_facts/ammonia_hazards.cfm•http://www.ammoniatraining.com •http://www.hft.e-technik.uni-dortmund.de•www.irc.wisc.edu/file.php?id=134 •http://www.marketwire.com/mw/release_html_b1?release_id=218681•www.iiar.org01/13/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-5IntroductionAmmonia•Compound with the formula NH3•Environmentally friendly gas•Does not deplete the Ozone layer•Does not contribute to global warming•Used in fertilizers, explosives and synthesis of organo-nitrogen compounds•Used as an ingredient in household glass cleaners•Due to its thermodynamic properties it is commonly used as a refrigerant01/13/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-6BackgroundWhy detect Ammonia?•Toxic chemical that requires reliable detection •Flammable between 16-25% by volume•Personnel and property protection•Ammonia is extremely irritating, burns skin on contact•Causes pulmonary edema , a build up of fluid in lungs, causing respiratory problems.01/13/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-7Detection-Methods •UV absorption -- require high sample volumes and long warm-up periods for accurate•NIR sensors -- expensive•Metal oxide sensors -- require extremely accurate temperature control for acceptable speciation •Electrochemical -- require frequent electrolyte replacement, need stable oxygen concentrations for operation, and respond to interferent gases such as carbon monoxide and chlorine01/13/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-8Principle of sensor •This gas sensor detects changes in capacitance caused by absorbed ammonia that alters the sensor’s relative permittivity. •The capacitance, C, of a capacitor is calculated from:01/13/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-9Figure 1122331. Capacitor2. Heating Resistor3. Measuring ResistorInside view of the sensor01/13/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-10Operation•The active layer is a polymer film that serves as a dielectric between the capacitor plates. Two resistors control the temperature of the capacitor; one heats the system and the other measures the sensor temperature and controls the heater resistor• The capacitance is proportional to the permittivity of the capacitor material. Absorption of ammonia changes the relative permittivity and hence the capacitance.01/13/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-11Operation•Ammonia and water molecules are absorbed into the active polymer layer at a collection temperature. To measure the ammonia concentration, the water must be removed. This task is accomplished by a controlled temperature cycling whereby the sensor is rapidly heated, the gases are desorbed, and then the sensor is cooled again to the collection temperature. Temperature-capacitance data pairs are measured at short time intervals during the cycle. Between the heating and cooling curves, the ammonia sorption causes hysteresis01/13/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-12Graph showing variation of capacitance with cycle temperatureThe ammonia absorption and desorption during the heating and cooling cycles causes hysteresis that is proportional to the amount of ammonia present.01/13/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-13Advantages over other sensors Many ammonia-sensing technologies exhibit temperature dependence and also give false alarms due to cross sensitivity to humidity and chemicals. This sensor is very selective to ammonia and therefore dramatically less prone to false alarms Featuresoperating temperature range –40°F to 140°F humidity range 0–100%.01/13/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-14Advantages•Because of their stability, the sensors require calibration annually; many electrochemical and semiconductor cells must be calibrated every few months. Interchangeable probes make maintenance quick and easy •The sensor is inexpensive compared to other sensors and easy in construction•Can be used in a variety of applications in sync with other apparatus01/13/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-15 The sensor are available in 2 models as shown in the above figure One is a basic sensor and the other is an advanced sensor with adjustable alarm relays01/13/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-16Sensor Specifications•0–20 mA/4–20 mA output •data logging for 800 measurement points •a self-diagnostic check, and a front panel with a clear LED traffic light display to indicate the operation level. •Service mode button that deactivates the outputs for 1 hr, useful when
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