Temparature measurement

[Reeq]

I am designing a temperature measurement circuit for measuring temperature of a oven. Temperature of the oven is around 650 K. I heard that thermistors and RTDs can be used for temperature measurements. But I couldn't figure out which is better. Can somebody give some suggestions ?

 

[VEBill]

650K is 377C.

There are also thermocouples.

Why are you designing this, as opposed to buying one? Is this for production, or one-off installation?

 

[DRWeig]

You won't be finding a thermistor for a temperature that high. 250°C is about the upper limit.

As for which is better, VE1BLL's thermocouple suggestion or an RTD: You need to consider the desired accuracy, cost, package, range, and other things.



Best to you,

Goober Dave

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[engineeringcalc]

RTDs are resistors, with a value that changes usually with the temperature. The more common type is PT100. However I think it is a very high temperature for a PT100. For that temperature I believe the correct choice would be a Thermocouple. Thermocouples provide a very week voltage signal, that you will have to handle with the proper electronic. There are many devices in the market that can read the thermocouple and provide a analog (4-20mA) signal that you can handle with a PLC etc.

Regards,

http://www.engineeringcalc.com

 

[btrueblood]

400 C is well within the usable range (to 600 C) for a platinum RTD, if it is properly constructed for high temp's. RTDs have better accuracy, linearity and repeatability than thermocouples, so may have advantages there. Whatever device is used, it should be designed to be fairly readily removed for calibration and/or replacement when it eventually breaks.