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I am doing an assignement and have been asked to find a TMS for a whiskey distillary and I cannot find a suitable RTD. The parameters are that it needs to have a T range between 0 and 120 degrees celcius and an Output range between 0mV and 120mV. The input range is 0V to 12V. I have said an RTD would be the best option.

the question asks to select a suitable tempreture sensor and find an example. I have said that the RTD would be the best option

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    \$\begingroup\$ Google says TMS = Transcranial magnetic stimulation. Sounds like fun. Let us know how it goes. \$\endgroup\$
    – Chris Knudsen
    Commented Oct 27, 2020 at 22:15
  • \$\begingroup\$ RTD is a broad category of devices, and there are hundreds that fit the bill for this application. Have you looked at thermistors (negative or positive tempco)? \$\endgroup\$
    – Reinderien
    Commented Oct 27, 2020 at 22:16
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    \$\begingroup\$ Also, when you say input voltage range and output voltage range, you're implying that there needs to be some kind of signal conditioning other than the RTD alone. If this is homework, what parameters are there on the assignment? Are you expected to come up with an active solution? \$\endgroup\$
    – Reinderien
    Commented Oct 27, 2020 at 22:18
  • \$\begingroup\$ Finally: when you say +/- 0.01C, is that the entire sensing range? Because 78.36-78.38 is possible, but awfully narrow. \$\endgroup\$
    – Reinderien
    Commented Oct 27, 2020 at 22:19
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    \$\begingroup\$ Your title implies a specification for accuracy of +/-10mK (rather difficult and very expensive/fragile an likely to have poor performance in terms of response time) or stability or maybe repeatability, or is it resolution (fairly trivial)? Also, avoid or define acronyms such as “TMS”, they are not commonly enough used to be thrown in there without explanation. \$\endgroup\$
    – Spehro 'speff' Pefhany
    Commented Oct 27, 2020 at 22:23

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It depends on your casual requirements and unspecified real requirements for relative and absolute error . You MUST be specific !! In more measurable tolerances.

I suggest you use the 0.1% absolute LMT70A and use a precision Vref and 0.1% resistors to level shift or use a pot to calibrate gain and offset using a CMOS RRIO Op Amp for converting gain and offset to achieve 1mV/‘C

cost <$10 1pc for everything needed.

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    \$\begingroup\$ The LMT70A does not meet the +/- 0.01C requirement. It's accuracy is specified as +/- 0.2C. A custom calibration would be required. \$\endgroup\$
    – Barry
    Commented Oct 28, 2020 at 1:51
  • \$\begingroup\$ Barry only SNR limit this since calibration was given as a simple low cost solution , an unspecified requirement which is casual or artificial, ambiguous is often perceived with invalid logic. Better criticism can only follow better question specs. He was referring to an RTD spec not the system requirements , when it is doubtful that an RTD is even needed. \$\endgroup\$
    – D.A.S.
    Commented Oct 28, 2020 at 2:21
  • \$\begingroup\$ How would i make it match the 12V requirement? \$\endgroup\$
    – Cameron Norrie
    Commented Oct 29, 2020 at 13:09
  • \$\begingroup\$ Using an inverting Op Amp with RRIO on Vdd=12 using a computed gain and offset to =6V using a band gap Vref....that is trivial, often solved on this site. \$\endgroup\$
    – D.A.S.
    Commented Oct 29, 2020 at 18:03

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