Platinum resistance temperature range - 200 ~ 850 ℃ metal platinum materials has the advantage of good chemical stability, high temperature, easy to produce pure platinum, and because of its resistivity p ( Ω? mm2/m) Big, can use less material resistance, in addition, the temperature measurement range. Its disadvantage is that: in the reducing medium, especially at high temperature is easy to oxide from contamination, reduction of the steam out of the platinum wire brittle, and the relationship between the change of resistance with temperature. - copper resistance temperature range 50 ~ 150 ℃ copper thermocouple, cheaper line a good degree, in - on the industry 50 - - Use more + 150 ℃ scope. Copper thermocouple afraid of damp, easy to corrode, low melting point as well. Thermocouples are widely used in industrial temperature measurement not only, and is made into standard benchmark instrument. But his due to his temperature measurement range application by certain restrictions, thermocouple temperature measurement principle is based on a conductor or semiconductor resistance changes with the change in temperature. Its many advantages, can also remote transmission signal, high sensitivity, strong stability, compatibility and accuracy are better, but you need to power, can't instantaneous measured the change in temperature. Industrial thermocouple usually use Pt100, Pt10, Cu50, Cu100, platinum thermocouple temperature measurement range is generally 200 - below zero 800 ℃, copper thermocouple is 40 to 140 ℃ below zero. Thermocouple and thermocouple type, but he does not need compensation conductor, and is much cheaper than thermocouple. Platinum thermocouple installation form a lot, have a fixed screw to install, thread installation, fixed flange installation, flange installation, pipe installation, straight pipe connector installation, etc. Thermocouple and the choice of the thermocouple is a big difference in the temperature range of choices, thermocouple is measuring the temperature of the low temperature sensor. General measure temperature in - Is 200 ~ 800 ℃, and the thermocouple temperature sensor in measuring high temperature, average temperature in 400 ~ 1800 ℃, when the choice if measuring temperature at 200 ℃ or so, should choose the thermocouple measurements, if the measure temperature in 600 ℃ should choose K type thermocouple, if the temperature of 1200 ~ 1600 ℃ should choose S type or B type thermocouple. Thermocouple compared with thermocouple has the following characteristics: 1, the output signal under the same temperature is bigger, is easy to measure. 2, must with the help of measuring resistance and power supply. 3, thermocouple temperature part size is larger, the thermocouple is a small solder work end, thus the reaction of the thermocouple temperature measurement speed is slower than the thermocouple; 4, thermocouple as thermocouple temperature measurement of similar material, high ceiling. Thermocouple and thermocouple difference: 1, the nature of the signal, thermocouple itself is the resistance, the change of the temperature, the resistance produce positive or negative resistance changes; And the change of the thermocouple is induced voltage, he along with the change of temperature change. 。 Although is non-contact thermometer table, but their different temperature range, thermocouple used in high temperature environment, such as platinum rhodium - 30 - - Platinum rhodium 6 ( B) Measuring range is 300 ~ 1600 degrees, 1800 degrees short-term measurable. S for a 20 ~ 1300 ( Short-term 1600). , K type a 50 ~ 1000, short-term 1200). 。 XK a 50 ~ 600 ( 800). , E a 40 ~ 800 ( 900). 。 And J type, T, etc. This kind of instrument is commonly used in over 500 degrees high temperature, low temperature zone thermoelectric potential output, while potential hours, against interference measures and the second table and requirement is high, otherwise the measurement, and, in the region of the low temperature, the change of the cold end temperature and the relative error caused by the change of environmental temperature is very outstanding, is not easy to get full compensation. At this time in low temperature, the general use of thermocouple temperature measurement range for a 200 ~ 500, and even measurable lower temperature ( If use carbon resistance of measurable to about 1 k) at low temperature 。 Now normal use platinum thermocouple Pt100, ( There are Pt50, 100, and 50 on behalf of the thermocouple at 0 degrees of resistance. In old dividing use BA1, BA2, BA1 at 0 degrees for 46 ohm resistance value, useful also copper resistance in the industry, index number is CU50 and CU100, but small temperature range, between the 50 ~ 150, and indium resistance in some special occasions, manganese resistance, etc. ) 。 2, in the work field judgment of thermocouple is negative, compensation conductor is divided into positive and negative, connection, first configure it. In the run. Common have short circuit, open circuit, poor contact ( A multimeter can judge) And metamorphism ( According to the surface color to identify) 。 Checks, to make a thermocouple is separated from the secondary table with tools short compensation line in the second table, table indicating at room temperature and sub thermocouple terminals, thermocouple in the ambient temperature (table batch No, compensation wire fault) That measure roughly with a multimeter mv file thermocouple thermoelectric potential ( Such as normal, please check the process) 。 Thermocouple short circuit and open circuit multimeter can be use to judge, in the running, doubt short circuit, as long as the end resistance will be removed a thread to see display instrument, such as the large, thermocouple, short circuit back to zero wire short circuit, ensure the normal connection and configuration, the table values showed low or instability, possibility of protecting tube into the display is very big, thermocouple show small open circuits. Third, from the material, the thermal resistance is a kind of metal materials, has a temperature sensitive metal materials, thermocouple is bimetallic material, both of two different metals, due to the changes of temperature, in two different electric potential difference at both ends of the wire. Fourth, the two kinds of sensors to detect temperature range is different, thermocouple 0 - general detection The temperature range of 150 degrees ( Of course can detect negative temperature) , can detect 0 - thermocouple Temperature range of 1000 c ( Even higher) So, the former is low temperature detection, which is high temperature detection.