I have a question for everyone: when using a PLC RTD module, what wiring method—three-wire or four-wire—ensures accurate resistance measurement?
Thread Content
I have a question for everyone: when using a PLC RTD module, which wiring method—three-wire or four-wire—is suitable for accurately measuring resistance? https://gss0.baidu.com/-Po3dSag_xI4khGko9WTAnF6hhy/zhidao/wh%3D600%2C800/sign=4054ea8fb2119313c716f7b6550820ef/0b7b02087bf40ad171cee3ae572c11dfa9ecce50.jpg As shown in the figure, when a+ and a- provide stable current sources and A+ and A- are used to measure voltage, doesn’t the four-wire/three-wire system still have the resistance of the A+ and A- wires? Is the difference due to an error? I hope an expert can answer this. Thank you all.
I know about balance bridges and things like that, but I’m not sure how RTD modules are used.
:Lol, go check out the post written by my brother and you’ll understand — in-depth explanation of the three-wire thermal resistance temperature measurement circuit: https://bbs.hcbbs.com/thread-1977228-1-1.html. . .
Thank you very much, I understand. :lol