How to distinguish PT100 thermal resistance and thermocouple probe

First, the nature of the signal, thermal resistance itself is 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 inaccurate; Also, in low temperature area, 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 use of thermal resistance temperature measurement range for a general 200 ~ 500, and even measurable lower temperature ( If use carbon resistance of measurable to about 1 k) at low temperature 。 Now normal use Pt100 platinum thermal resistance, Also have Pt50, 100 and 50 representative value of thermal resistance at 0 degrees. 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, two kinds of sensors to detect temperature range, thermal resistance test 0 - in general 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.

the third, from the material, thermal resistance is a kind of metal material and temperature sensitive change of 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.

4, in the work site judgment

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) 。

thermal resistance short circuit and open circuit with a multimeter can determine, in the running, doubt short circuit, as long as the end resistance will be removed a thread to see display instrument, such as, thermal resistance, 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 water show, the largest thermal resistance circuit according to the minimum short circuit.