Timeline for How are and what are the sources coupled to a 3-wire RTD leads? [duplicate]
Current License: CC BY-SA 4.0
14 events
| when toggle format | what | by | license | comment | |
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| May 23, 2019 at 11:24 | vote | accept | user1999 | ||
| May 22, 2019 at 17:43 | comment | added | user1999 | I understand that but Im not asking that. Im asking does R3 (in the very bottom of the question after the edit) have to be equal to R2. I can understand why R1 and R2 are equal. But Im asking does the value of R3 matter. Hence does the value of sensing wire’s resistance matter? | |
| May 22, 2019 at 9:56 | comment | added | KalleMP | Look at the datasheets of industrial ADC ICs and see the explanations for their input circuits for connecting to 3 wire RTDs. The idea is to use the extra wire to sense the volt drop due to the sensor current and subtract twice that drop from the measured voltage to determine the sensor resistance while compensating for the wires. In essence it allows arbitrary thick, thin, long or short wires as long as all three are the same (in theory one wire can be different if you make sure it will be the zero current wire). | |
| May 21, 2019 at 19:15 | comment | added | user1999 | But R3 is taken equal with R2 and R1 I dont get why. Im scratching my hair | |
| May 21, 2019 at 19:06 | comment | added | D.A.S. | R1,2,3 are just cable resistance, but R3 carries no current so for a really long current loop it is basically 1/2 of a Kelvin bridge. | |
| May 21, 2019 at 19:00 | review | Reopen votes | |||
| May 22, 2019 at 12:20 | |||||
| S May 21, 2019 at 18:41 | history | edited | user1999 | CC BY-SA 4.0 |
R3 is floating what is the use of it?
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| May 21, 2019 at 18:34 | review | Suggested edits | |||
| S May 21, 2019 at 18:41 | |||||
| May 21, 2019 at 18:12 | history | closed |
Andy aka Dave Tweed |
Duplicate of How does 3-wire RTD or resistance measurement works in bridge of wheatstone? | |
| May 21, 2019 at 14:55 | history | edited | user1999 | CC BY-SA 4.0 |
added 367 characters in body
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| May 21, 2019 at 14:25 | review | Close votes | |||
| May 21, 2019 at 18:12 | |||||
| May 21, 2019 at 14:17 | history | edited | user1999 | CC BY-SA 4.0 |
added 171 characters in body
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| May 21, 2019 at 14:04 | answer | added | Arsenal | timeline score: 0 | |
| May 21, 2019 at 13:46 | history | asked | user1999 | CC BY-SA 4.0 |