PT100 3

[NSMNEA]

Hey guys I'm an Instrumentation tech in Australias north west,
I have noticed that when setting up temperature transmitters that when setting them up for pt100 it will ask you if it is PT100(385) or 395, 3916 etc.

does any one know what this last figure is in relation to as it would be nice to know what i'm setting them as, usually the type is written on the side of the tx but more for my own knowledge.

Regards
Mario

 

[danw2]

It's the temperature coefficient.

From Omega's site:

2.Temperature Coefficient
The temperature coefficient of an element is a physical and electrical property of the material. This is a term that describes the average resistance change per unit of temperature from ice point to the boiling point of water. Different organizations have adopted different temperature coefficients as their standard. In 1983, the IEC (International Electrotechnical Commission) adopted the DIN (Deutsche Institute for Normung) standard of Platinum 100 ohm at 0ºC with a temperature coefficient of 0.00385 ohms per ohm degree centigrade. This is now the accepted standard of the industry in most countries, although other units are widely used. A quick explanation of how the coefficient is derived is as follows: Resistance at the boiling point (100ºC) =138.50 ohms. Resistance at ice point (0ºC) = 100.00 ohms. Divide the difference (38.5) by 100 degrees and then divide by the 100 ohm nominal value of the element. The result is the mean temperature coefficient (alpha) of 0.00385 ohms per ohm per ºC.

Some of the less common materials and temperature coefficients are:

Pt TC = .003902 (U.S. Industrial Standard)
Pt TC = .003920 (Old U.S. Standard)
Pt TC = .003923 (SAMA)
Pt TC = .003916 (JIS)
Copper TC = .0042
Nickel TC = 0.00617 (DIN)
Nickel TC = .00672 (Growing Less Common in U.S.)
Balco TC = .0052
Tungsten TC = 0.0045

 

[NSMNEA]

awesome thankyou mate that answers my question