Timeline for RTD sensor circuit design
Current License: CC BY-SA 4.0
6 events
| when toggle format | what | by | license | comment | |
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| May 21, 2018 at 17:12 | comment | added | user76844 | By the way. If you are worried about the wire resistance (i don't think you should be, but still), go for 4-wire scheme, which is in fact much like 4-point resistance measurement. | |
| May 21, 2018 at 17:09 | comment | added | user76844 | Glad you understand. Did you understand that you don't need current source? Did you understand why? Do you understand why simplicity matters? | |
| May 21, 2018 at 17:02 | comment | added | Emily L. | Ok so what you're describing is a voltage divider and you want to take the voltage at the midpoint. This is not a pull-up. A pull up is used to drive a line high when there is no one actively driving it low. Using a voltage divider like that was my first idea and I discarded it early in the process. Then I did the amplification/shifting as in the question. And maybe it would work with that circuit. | |
| May 21, 2018 at 16:27 | comment | added | user76844 | Makes no sense because little experience, sorry. So pull up meaning it's enough to do like that: 5V -\/\/\- PT100 GND. The redistor- 5k, so the current will be around 1mA. Voltage on PT100 is amplified by analog amplifier (very simple) with some gain (probably 30 to 50) and bandwidth (probably 100Hz to 1kHz). That's it. Very simple, otherwise it's for advanced engineers. In your MCU you can do running average, that's the most "complex" digital filter you may need for this application. Is it more clear now? | |
| May 21, 2018 at 16:20 | comment | added | Emily L. | I'm sorry but your explanation makes no sense to me. Using a pull up to measure is a foreign concept as it's just a resistance to Vcc. It doesn't measure anything... What do you mean by filter? Analog domain? Digital domain? I did the simulations for my circuits and circuit analysis to determine the gains and offsets. | |
| May 21, 2018 at 6:14 | history | answered | user76844 | CC BY-SA 4.0 |