Platinum resistance temperature detector

Resistance temperature detector. In the low-medium temperature range, thermometers based on resistometry are often used. A reference high-accuracy thermometer is the platinum resistance temperature detector which may be used as an interpolation standard in the temperature range from the triple point... 

Figure 2.1 Thermal behavior of a thermistor [1] and a platinum resistance temperature detector (RTD) [2],...

Temperature sensors are non-invasive and can be attached to either flat or curved surfaces. Platinum resistance temperature detectors may be used to measure the temperature of items with a low mass... 

Calibrate the gas chromatograph column oven temperature sensors using an independent, electronic temperature measuring device such as a thermocouple or platinum resistance temperature detector. 

Temperatures can be measured with thermocouple (T/C) or resistance temperature detector (RTD). RTD provides for stability its variation in temperature is both repeatable and predictable. T/Cs tend to have shorter response time, while RTDs have less drift and are easier to calibrate. RTD provides for stability its variation in temperature is both repeatable and predictable. RTD contains a temperature sensor made from a material such as high purity platinum wire resistance of the wire changes rapidly with temperatures. These sensors are about 60 times more sensitive than thermocouples. 

Example For pure platinum metal (a = 0.00392 K ), which is used extensively in high-precision devices for accurate temperature measurement called resistance temperature detectors (RTD), the coefficient of temperature for the resistance of 100 ohms between the freezing point (0°C) and the boiling point of water (100"C) is a = 0.00385 K [RTD of Class B according to standard lEC-751]. 

Resistance temperature detectors (RTDs) are based on the principle that the electrical resistivity of most metals increases predictably with temperature. Platinum is the preferred metal for RTDs, although other less expensive metals are used in some applications. The resistivity of platinum is one of the standards by which temperature is measured. The relatively good linearity of the resistivity of platinum over a wide temperature range (—200-800° C) makes platinum RTDs suitable for stable, accurate temperature transducers, which are easily adapted to control systems apphcations. 

Resistance Temperature Detectors, Rgure 1 (a) The normaiized resistance of an industrial platinum resistance thermometer 0PRT or RTD) as... 

Resistance Temperature Detectors, Table 1 Temperature accuracy of industrial platinum resistance thermometers (IPRTs) according to the most common standard, which is known variously as lEC, DIN, ASTM, 0.00385-type, and/or the European curve. Note that t is the temperature in degrees Celsius... 

Platinum Resistance Thermometers (PRTs) PRTs (sometimes seen as Resistance Temperature Detectors, or RTDs) are the thermometers of choice in high-quality blackbodies. They are reliable and accurate, although they require recalibration every 2 or 3 years. They are generally used with dedicated blackbody controllers that measure the PRT resistance, convert it to temperature, and adjust heaters to maintain the desired temperature. These controllers are programmable to accept calibration constants they convert the measured PRT resistance to temperature using the Callendar-Van Dusen equation ... 

Resistive Thermal Detectors (RTDs) RTDs determine temperature by measuring the change in resistance of an element due to temperature. Platinum is generally utilized in RTDs because it remains mechanically and electrically stable, resists contaminations, and can be highly refined. The useful range of platinum RTDs is... 

Temperature control is normally carried out using thermocouples in a stainless steel pocket. The type of thermocouple used is either a platinum resistance detector (RTD) or a thermocouple using two dissimilar metals that produce a voltage (EMF). The indicators for these thermocouples must match the probe type and grade. The positioning of the probes is very important as well as any lag (delay) in the system. The output from the probe is connected to the indicator and/or controllers. Most indicators have at least a set point with an on/off output. The more advanced units will allow anticipated switching, more than one set point, temperature ramping between temperatures, time, and hold facilities. Thermocouple break and over-temperature alarm outputs are also commonly provided features. 

The first bolometer produced by Langley in 1880 used a platinum resistance element and later other metals (such as nickel) were used. These metals are still used for resistance thermometers where their high long term stability is an essential requirement. For infrared detectors, however, the older metal film bolometers have been replaced by semiconducting elements which have a much larger temperature coefficient. 

The system applied in the study mentioned above consisted of a CDS model 122 Pyroprobe with a ribbon filament as the heating surface (see Chapter 3 and Appendix 1). This pyrolyser heats by varying the resistance of the platinum element. Temperature rise times for flash pyrolysis are typically of the order of milliseconds. IR spectra were obtained with an FT-IR bench system equipped with a CDS pyrolysis/FT-IR interface. The data were collected at 8 cm" with a deuterated triglycine sulfate (DTGS) detector. The interface is cylindrical in shape with two potassium bromide windows for the IR beam to pass through. 

Temperature detector, resistance RTD contains a temperature sensor made from a material such as high purity platinum wire resistance of the wire changes rapidly with temperatures. These sensors are about 60 times more sensitive than thermocouples. 

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