Daily Question on Automation Theory Knowledge (8.30)

Thread Content

This post was last edited by 18663069001 on 2017-8-29 at 21:26. Process and instrumentation are inseparable; to help everyone gain a better understanding of the basic concepts related to instruments, we have launched the \"One Question per Day\" initiative – just reply to get the answer. To encourage continued participation from everyone! You get 3 wealth rewards just for participating! Higher rewards for correct answers! I hope everyone will participate actively, learn together, and make progress together! ! ! Multiple-choice question: 45. If the compensation wire of a thermocouple is connected incorrectly, the instrument reading will ( ). A. Be too high B. Be too low C. Be either too high or too low depending on the specific situation D. Remain unchanged. The answer to this question is C. 1. When the temperature at the connection point between the thermocouple and the compensation wire is higher than the temperature in the control room, the compensation potential of the compensation wire is positive; it should be the thermoelectric potential generated by the thermocouple 【plus】 the compensation potential generated by the compensation wire. If the connections are reversed, it’s equivalent to adding a negative value, which results in a lower reading ； 2. When the temperature at the connection point between the thermocouple and the compensation wire is lower than the temperature in the control room, the compensation potential of the compensation wire is negative. The thermoelectric potential generated by the thermocouple should be [subtracted] from the compensation potential generated by the compensation wire; if this order is reversed, subtracting a negative value will result in an overestimated reading ； 3. When the temperature at the junction where the thermocouple is connected to the compensation wire is equal to the temperature in the control room, the compensation potential of the compensation wire is zero, and this has no impact on the measurement