Temp Logger - RTD ??

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#1
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I'm working on a remote BBQ temp logger, and I've got 4 channels of thermocouples using the MAX6675 - I've got a few a/d ports left and was wondering if there is an easy chip/circuit for adding RTD's ?? Most of the IC's I've seen are very very pricy.

Thanks

Les

next time for shure.

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What do you mean by "very very pricy"? What is your target price? Also, why not add some more MAX6675s or MAX31855s using the extra A/D lines as digital IO for the CS pins?

-Pantelis

Professor of Applied Murphology, University of W.T.F.Justhappened.

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pricy was in the $60/chip for RTD conditioner chips, the reason for adding teh RTD availability and price of existing BBQ RTD sensors is substantially cheaper than thermocouples (~ $5/probe -vs- $10-90 for type K probe) The jacks on hte RTD's are also a little cheaper than for the thermocouples. I would like a conditioner in the $5-10 range. (prices in US dollars)

next time for shure.

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Something like that? Though you will have to compensate for the RTD nonlinearity in software.

Then there is also the XTR family from Texas Instruments that does the linearization on chip.

-Pantelis

Professor of Applied Murphology, University of W.T.F.Justhappened.