Platinum Resistance Thermometers – PT1000

PT1000

The PT1000 is a platinum resistance thermometer similar to the Pt100. It’s one of the most common platinum resistance thermometers out there and compares and contrasts to the Pt100 in many ways. Its element is Platinum in nature which in turn gives it a resistance of 1000ohms @ 0ºC. The name Pt1000 comes from the 1000ohm of resistance the thermometer has. Pt is the periodic name of Platinum, used to make these sensors. They can be purchased at specialist vendors such as Process Parameters but can also be found on marketplaces like eBay.

Why Pt1000s and Pt100s are increasingly common

Sensing wires in RTDs can range from copper to nickel and finally tungsten. However, Platinum is by far the best metal used to date. While some might argue that Platinum is costly than the other materials above, it’s still worth the price. Platinum has several characteristics that make it excel at temperature measurement. These characteristics include:

  • – Platinum has an almost linear relationship between temperature and resistance.
  • – Platinum sensors are highly accurate and are very consistent too.
  • – Also, it has the highest resistivity compared to the elements above. For example, it beats nickel by 23 Ω/cmf, even though nickel is one of the elements with the highest resistance of 36 Ω/cmf.
  • – Additionally, Platinum has excellent stability compared to the elements mentioned earlier.
  • – As if that is not enough, Platinum’s resistance is non-degradable. And as such, its resistance will remain constant even if it’s used severally.
  • – Last but not least, Platinum has a good chemical passivity.

What is the difference between the Pt100 sensor and the Pt1000 sensor?

The most significant difference between the two sensors is the resistance of each. The nominal resistance between the two is different. The pt1000 sensor has a resistance of 1000 Ω while the pt100 sensor has 100 Ω. The 1000 Ω and the 100 Ω resistance apply for the sensor’s ohmic value at 0°C.

Another talking point for these two RTDs is their common temperature coefficient of resistance. However, since there’s a factor 10 difference between the Pt100 and the Pt1000 sensors. There’s a resultant difference when you compare the two sensors in a 2-wire configuration. In short, the two have different measurement errors between them. For starts, the Pt1000 has a measurement error of 0.1°c while its counterpart has its error at +1.0°C.

So, which RTD model should I go with?

Knowing the resistance levels of both sensors, it’s great to note that they’ll work well in either a 3 or 4 wire configuration. The extra wires in these configurations will effectively come in hand and compensate for the sensor’s resistance. Additionally, the two sensors have a common price, but the Pt100 is still preferred for the following reasons.

  • – Pt100 sensors not only have wire-wounds but also have thin-film constructions. As such, these features offer the user flexibility and a choice to decide which configuration suits them. The same can’t be said for Pt1000s which only have thin-films
  • – Lastly, they are compatible with industrial instruments and processes.

Having noted the above advantages, why would individuals still opt for Pt1000 sensors. Individuals will always opt for the Pt 1000 if their nominal resistance is greater or are facing the following scenarios:

  1. 1. Installing sensors on 2wire configurations. 2wire configurations with longer lead wires would require technicians to install the Pt1000 over the Pt100. Designs with 2wire configurations compensate for fewer wires with length. As such, the resulting resistance of the wire would be more than expected. Using a Pt100 sensor inside such a configuration would only result in inaccuracies and errors when reading temperatures. To deal with this, technicians would rather the Pt1000 sensors since the resistance would comfortably compensate for these errors.
  2. 2. While the Pt100 might shine as a flexible sensor, it’s not suitable for battery-operated applications. This is the domain of Pt1000 sensors. Pt1000 sensors use less electrical current, thus requires less power to operate. In turn, this low power consumption extends the battery life and reduces any maintenance costs that might be needed. As such, this indirectly reduces industrial downtime and costs that would otherwise be spent on maintenance.
  3. 3. Also, Pt1000 sensors are unlikely to overheat, unlike Pt100 sensors. Pt1000 sensors use less power. As such resulting in fewer errors in reading super high temperatures.

All in all, Pt100 sensors are common in process-applications. On the other hand, its counterpart is standard in machine building applications, refrigeration, heating systems, vents, and automotive.

Replacing RTDs| The does and don’ts

While most individuals think that replacing RTD sensors is as easy as the ABC, it’s not. Replacing an RTD must meet the standards set by your country. So, whether you are replacing a Pt100 or a Pt1000 sensor, you should go through your country’s regulations. If you have a problem replacing it on your own, find a technician to do it for you. It’s better to be safe than pay dearly for failing to meet regulations.

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