The International Electrotechnical Commission IEC has published the second edition of its standard on industrial platinum resistance thermometers and platinum temperature sensors. This site uses Akismet to reduce spam. Although conforming to the use of a 0.
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Kelvin and Rankine, which are absolute temperature scales, and Celsius and Fahrenheit, which are not. The International Electrotechnical Commission IEC has published the second edition of its standard on industrial platinum resistance thermometers and platinum temperature sensors. Then you need to spell out your requirements for the applications engineer.
Specific changes in the new edition include: Aside from these cases, it is generally better to state your requirements in terms of temperature tolerance in degrees over the temperature range where it is actually required. Temperature is standarf of the most irc used parameters in industry, and accuracy in its measurements is critical for the chemical, pharmaceutical, metal, and food sectors. If you need to know only, "Is it hot or is it not? It is important to understand that just like K-Type thermometers there are 3 main areas of uncertainty when using Pt thermometers.
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IEC revises standard on thermometers and sensors
The class of the probe dictates how much the probe can drift away from uec curve. Each probe has the capacity to drift away from this curve reducing accuracy. Because a standadd manufactured RTD will have high repeatability relative to the applicationClass B accuracy is generally sufficient unless there is a need for better interchangeability; or when measuring change of temperature; or if you know that you have special accuracy requirements.
This would be displayed as follows this is an example only Sgandard Temperature Thermometer Reading The uncertainty of measurement for the thermometer is. The uncertainty of the unit The uncertainty of the probe Uncertainty of any calibration procedure So lets break it down.
The Calibration Temperature — This is the temperature the thermometer is being tested stanvard The Pt Thermometer reading — This is the reading the Pt thermometer gave at this known temperature The uncertainty remaining at the calibrated temperature points.
Of course, classes A and B or grades A and B cannot cover every possible accuracy specification desired. Hi Santhu, It is just a case of accuracy. Specific changes in the new edition include:. In the examples below we used our own Pt model. There are four primary temperature scales in use today.
These are IEC designations of accuracy. But remember, when specifying a Class A RTD, you must always include the working range at which it must perform to this accuracy.
Pt RTD Colour codes IEC
Possible, but not likely. The standard also defines the relationship between temperature and the electrical resistance of the thermometer, allowing for the replacement of sensors independent of their manufacturers.
The minimum and maximum temperatures of the stated working range are conve-nient points to chose and will ensure Class A accuracy, but will at the same time tend to drive up the cost of the sensor.
But as the temperature increases, so does the permissible deviation due to the variations possible in the TC.
As we discussed earlier, you may not actually need the accuracy at this point, but rather the repeatability. It is more practical to look the application. The specification was poorly written. Each probe has a different level of tolerance.
ATP Instrumentation Ltd
The Future of Manufacturing: The Maintenance Supervisor Enigma. Let's take the freezing point of water in Celsius for example. The standard specifies 4 classes of accuracy. From our previous calculations we know that at the standard calibration temperature points we offer, our own Pt with a Class B probe would normally have the iecc accuracy uncertainties.