Request an explanation for dual-core thermal resistors
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At work today, I replaced a dual-core thermistor; since I usually deal with single-core thermistors and thermocouples. The instructor isn’t here again today, so I have to turn to the experts on the forum to help me clarify a question in my mind: does a dual-core thermistor mean it has two thermistors inside? So there are six terminal blocks? Similarly, does a two-core thermocouple have four terminals? What are the advantages of dual-core thermoresistors (pairs) compared to single-core ones? Where is it mainly used? Are there any types with more than two cores in addition to the two-core thermistor (pair)? Thank you.
Yes, a dual-element thermistor consists of two resistors that are independent of each other. The reason for this is that if the temperature needs to be measured in two different locations, a dual-element thermistor is used. It is also used to provide redundancy at very important temperature points. The principle is the same as that of thermocouples; I haven’t seen any more examples yet, but I believe they do exist.
Those with more cores use multiple thermocouples for fertilizers; there are several of them
Generally, dual (multiple) thermocouples are more common, while thermal resistors are usually single-unit types since it is easier to replace them when the temperature of their medium is low. Dual-element thermistors are used for measuring the surface temperature of unit coils and in other locations where disassembly and assembly are inconvenient.
Dual-core thermoresistors or thermocouples are generally used in monitoring environments where process requirements are stringent or where replacement is difficult, serving as backup points or for dual-location display.
Everything upstairs is correct! But that doesn’t mean a dual-core design must necessarily have six contacts!
1. Set redundancy at very important temperature points as well. 2. There are also those used in measurement, which can reduce external measurement errors and improve accuracy.
For relatively important process parameters, if temperature display is required along with control, then two temperature measurement points are needed. Using a two-wire thermistor (pair) is normal.
For a two-core resistor, which consists of two resistors, the labels are usually set as a and b; this improves accuracy, as the average value can be calculated； It is used at temperature measurement points where the temperature sensors are prone to damage, such as in environments with high vibration or strong corrosion. It improves stability at critical temperature measurement points, and the programming logic can be set to enable functions like tripping and reset via a 3-to-2 selection ； Special process sequences are set up, with a single temperature measurement point providing two OI points, and so on
At work today, I replaced a dual-core thermistor; since I usually deal with single-core thermistors and thermocouples. The instructor isn’t here again today, so I have to turn to the experts on the forum to help me clarify a question in my mind: does a dual-core thermistor mean it has two thermistors inside? So there are six terminal blocks? Similarly, does a two-core thermocouple have four terminals? Yes. What are the advantages of dual-core thermoresistors (pairs) compared to single-core ones? Where is it mainly used? There are no significant advantages; it is mainly used in situations where dual outputs are required, such as one output for connection to on-site display instruments and another for transmission to the control center. Are there any types with more than two cores in addition to the two-core thermistor (pair)? Thank you. In the reaction tanks of the chemical industry, there are reactors with more cores; we have worked on ones with 5–7 cores.