3-wire constant current/constant voltage temperature measurement circuit

zhouf2323

3-wire constant current/constant voltage temperature measurement circuit [Copy link]

Dear experts, I don't understand the two circuits above. The three-wire temperature measurement is to avoid the influence of line resistance. In the constant voltage circuit above, pt100 obviously has three wires, and there is nothing wrong with it. But in the constant current temperature measurement below, I can't see the meaning of the three-wire system at all. Is this line resistance ignored in the constant current case? I am confused, please give me some advice

qwqwqw2088

There are many ways to connect PT100, including 3-wire, 2-wire, and 4-wire. The constant current temperature measurement below is a 2-wire connection.

zhouf2323

qwqwqw2088 posted on 2018-10-17 14:23 There are many ways to connect PT100, including 3-wire, 2-wire, and 4-wire. The constant current temperature measurement below is a 2-wire connection

Can the constant current below be changed to a 3-wire circuit?

qwqwqw2088

zhouf2323 posted on 2018-10-17 15:02 Can the following constant current circuit be modified to become a 3-wire circuit?

There are many ways to connect PT100. You can refer to the above circuit for constant current temperature measurement and ground the other end.

chunyang

The figure below shows a two-wire constant current connection method. The circuit for the three-wire constant current connection method is different. You can look up the specific circuit in a book or search on the Internet.