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Edited

Link to Pt100 sensor (That's the best i could do)

https://www.intech.co.nz/products/temperature/mrh.html

Link to ESP8266 datasheet

http://www.handsontec.com/pdf_learn/esp8266-V10.pdf

Original

First of all, I am bit of a noob in electronics so i beg your forgiveness.

So i have a question. I have a manufacturing process where we "melt" resin into liquid form and i want to keep track of the temperature (range probably about 100-200 'C ) in an IOT way (Web dashboard, MQTT).

I am thinking of using a 3 wire PT100 with a ESP8266 Nodemcu using wheatstone bridge configuration. The sensor i am thinking of using will look something like this

enter image description here

Questions:

  1. The equipment on which i will be fitting this sensor will be essentially a very large vessel and most probably there will be chances of the whole probe getting submerged in the liquid resin. How this will effect my reading ? Can this create complications or even damage the probe.

  2. I am not able to find a circuit schematics for a 3 wire Pt-100. I will be really glad if somebody could literally spoon-fed me on how to make the circuit.

Thanks !!!

Sanchit Agarwal
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  • Can you edit your question to add links to the PT100 and ESP8266 datasheets? – evildemonic Dec 20 '18 at 18:33
  • Can't you just find a temperature controller that has a 3-wire input? Building your own is like Brain Surgery Self Taught Also, using a PT1000 might work if the cable is reasonably short. – Robert Endl Dec 20 '18 at 19:32
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    @evildemonic question has been edited. Please check – Sanchit Agarwal Dec 22 '18 at 05:30
  • @RobertEndl Won't be cost effective. Plus i know a bit or two about the basics. I already have a prototype ready with an IR temperature sensor but it is not helpful for my usecase. – Sanchit Agarwal Dec 22 '18 at 05:31
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    If you're going to use an industrial PT100, you should also use an industrial PT100 transmitter. Get one that outputs 0-10v, and feed that into your ESP 8266 with a resistor divider. You can also use the 4-20ma version which is more resistant to noise, but the wiring is slightly more complicated. – Drew Mar 21 '20 at 07:37
  • MAX31865 or similar IC? – NStorm Nov 18 '21 at 05:23

1 Answers1

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enter image description here

Found this on Bing. The opamps are obviously r-r and low voltage so they would not be easy to substitute. You may or may not want to calibrate this depending on the accuracy you need.

https://www.analog.com/media/en/reference-design-documentation/reference-designs/CN0337.pdf

Robert Endl
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