How is the average temperature measured?
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I just can’t figure it out – the resistance is much greater than that of the thermocouple, with the cold end at the same temperature
Can measuring the parallel voltage of three resistors give the average potential?
1. In this circuit, the total current I_total is generated as a result of the thermoelectromotive force passing through resistors.
2. In addition to keeping the cold end at a constant temperature, it is also necessary that R1 = R2 = R3.
3. The average thermoelectromotive force is calculated as: U_avg = I_total ÷ 3 × R1.
4. The thermoelectromotive force U can be found by referring to a table: U = U_avg + U_cold
2. In addition to keeping the cold end at a constant temperature, it is also necessary that R1 = R2 = R3.
3. The average thermoelectromotive force is calculated as: U_avg = I_total ÷ 3 × R1.
4. The thermoelectromotive force U can be found by referring to a table: U = U_avg + U_cold
Oh, this is used to measure the total current. It’s basically like connecting a thermocouple and a resistor in series, with these three components connected in parallel to measure the total current in the main circuit, thereby calculating the average temperature, right?
It can also be regarded as the average potential generated by three thermocouples; actually, that is an ammeter. Got it, thank you so much
By posting this image, the parallel connection of the thermocouples is correct; using this connection to calculate the average value results in a relatively small additional error. . . It is incorrect to connect N thermocouples in parallel directly without using a resistor to measure the average temperature! It’s wrong! It’s wrong! There are many textbooks that contain incorrect diagrams and wording in this section, misleading many people. . . Furthermore, modern instruments rarely use this circuit configuration these days; after all, it introduces variable errors. For more precise measurements, it is now common to directly feed the signals from each thermocouple into the amplifier in sequence, sample and calculate the temperature values for each channel, and finally compute the average temperature to update the data.
Just feed the temperature directly into the DCS to calculate the average. Is DCS still not available where you are?
I tried to learn it, but I gave all the circuit knowledge back to the teacher.
I only saw this in a book; I don’t quite understand it, so I’m coming to ask