Heating of the RTD wire leads 3

[JoseDRG]

Hi,

I'm working on a temporary fixture that will use an RTD to measure the temperature of a flat surface. The design might allow for the wires to the RTD to heat up to about 300F. Will this effect the performance/accuracy of the RTD significantly?

Any insight will be helpful.

 

[IRstuff]

Depends on the relative resistances, don't it?

TTFN

FAQ731-376

 

[zekeman]

I doubt it.
First, the allowable temperature of the wiring to the RTD probably limits the temperature of the RTD environment but heat transfer from the wires should be miniscule.

 

[IRstuff]

50 ft distance using 30 gauge copper adds 10.3 ohms

230°F rise changes that resistance by 5.3 ohms

5 ohm error in 100 ohm platinum RTD is about 2°C error

TTFN

FAQ731-376

 

[btrueblood]

Use a 3- or 4-wire RTD if you are concerned.

 

[JoseDRG]

Thanks for your help however, I do have another questions.

The RTD is not fixed to the surface that it is measuring; contact will be done with slight pressure and no thermal conductive epoxy between the RTD and measured surface will be used. Can I expect accurate results?

Thanks for your help.

 

[ione]

Thermocouple T (range -328 °F to 752 °F) could be an option. There are available models specifically conceived for flat surfaces.

 

[hacksaw]

most modern rtd's are flat unless they've neen encapsulated

how to you intend to account for radiation effects in your measurment?