Linear PT100 temperature sensor using method
linear temperature sensor is linear output negative temperature coefficient ( The NTC) Thermal element, it is actually a kind of linear temperature - Voltage conversion element, that is, in general working current, 100uA） Conditions, the voltage is linear change with the temperature of components so as to realize the linear transformation of non-electricity to electricity. What is the main characteristics of the linear NTC temperature sensor?
the temperature sensor is its main feature is the temperature - working temperature scope Voltage relations as a straight line, for the secondary development of temperature measurement, temperature control circuit design, will be without linearization, can complete the design of the temperature or temperature control circuit, thus simplify the design and debugging of instrument. Linear NTC temperature sensor temperature range is how to provide?
in terms of the total, temperature range, can be in Between 200 ℃ ~ + 200 ℃, but considering the actual needs, generally do not need to such a wide temperature range, and three different sections, to adapt to the different packaging design, at the same time in the selection of extension is also different. Linear temperature sensor for temperature compensation is special, set the working temperature range for - only 40℃～+80℃。 Can completely satisfy the general circuit of temperature compensation. Selection of extension shall comply with the principles of what?
in - general 200～+20℃、- 50 ~ + 100 ℃ advisable choose ordinary double glue line; In the range of 100 ~ 200 ℃ should choose high temperature line. What is the meaning of the reference voltage?
reference voltage is refers to the sensor under 0 ℃ temperature field ( Ice water) In general, taking the working current ( 100μA） Conditions, the voltage value of the sensor. In fact is the point of zero voltage. The symbol for V ( 0) The factory calibration, the value, because the temperature coefficient of sensor S are the same, as long as know the benchmark voltage V ( 0) Any temperature point, knowledge of sensor voltage value, without sensor for indexing.
the calculation formula is:
V ( T） =V（ 0) + S (T
example: such as reference voltage V ( 0) = 700 mv; S = - temperature coefficient 2 ℃ mv, then at 50 ℃, the output of the sensor voltage V ( 50) = 700 - 2×50=600（ mV） 。 This is the value of linear temperature sensor is better than the other temperature sensor. The temperature coefficient S mean?
temperature coefficient S refers to the regulation of working conditions, the output of the sensor voltage value of the ratio of change and temperature change, namely every 1 ℃ temperature change sensor output voltage value of change: S = delta V delta T ( mV℃） 。
temperature coefficient is the physical basis of linear temperature sensor for temperature measuring element, its role is similar to B value of the thermistor, the parameters in the whole operating temperature range is the same value, namely - 2 ℃ mv, and various types of sensor is the same value, that the traditional thermistor temperature sensor is incomparable. Swap the parameter precision of what's the point?
swap accuracy refers to work in the same conditions, The same working current, the same temperature field) For the determination of the same ideal fitting line to each sensor voltage V ( T） — T temperature curve and the maximum deviation of straight line, this deviation is often according to the temperature of the sensor, Voltage conversion coefficient S converted into temperature. As a result of the sensor output linearization and temperature - Voltage conversion coefficient is the same, that is, within the scope of temperature to the swap, so the exchange said the reference voltage value of the discrete degree of accuracy, temperature converted into discrete values of reference voltage values are used to describe the size of the degree of interchange between the whole batch of sensor. Generally divided into three: class I swap deviation is not more than 3 ℃; J level is not more than 5 ℃; K level is not more than 10 ℃.
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key words: thermal resistance, thermocouple, thermal resistance, platinum resistance, PT100, PT1000, pressure sensor and digital temperature sensor