Pt1000 measuring resistor
The scale for measuring temperatures
Resistance thermometers with a Pt1000 sensor are very important in temperature measurement. The sensors made with platinum change their degree of resistance according to the temperature. The resistances are divided up according to accuracy into the classes A, B and AA, as per IEC 60751:2008.
A distinction is also made as to whether a single or double Pt1000 is needed. With a double Pt1000, two measuring resistors are installed next to each other in a single thermometer. This arrangement is needed if two signals are being processed. The signal from the first Pt1000 measuring resistor is used for the control, and the signal from the second Pt1000 is used for the display device.
Many different designs, depending on the area of application
Of note here are the Pt1000 screw-in resistance thermometers, which are also known as screw-in Pt1000 temperature sensors. These feature a sensor consisting of a stainless steel housing equipped with a thread, making it suitable for screwing into threaded holes. This produces a fixed, defined position of the measuring point.
A further version of the Pt1000 temperature sensor is the Pt1000 surface resistance thermometer, also known as a Pt1000 surface sensor. As the name suggests, this is designed to measure surface temperature using a Pt1000.
Pt1000 temperature sensors are also used as Pt1000 sheathing resistance thermometers. In this instance, the Pt1000 measuring resistor is installed in a mineral-insulated solution and weld-sealed at the front. A sheathing resistance thermometer can be bent along its length.
To process the output signal produced by a Pt1000 thermometer, for example to connect it to a PLC, a Pt1000 transducer is required. A signal of 4-20 mA is then output or, in the case of a Pt1000 transducer, 0-10 V.
Temperature/resistance relationship table PT 100 & 1000
|t [°C]||R0=100 [Ω]||R0=1000 [Ω]|
|t [°C]||R0=100 [Ω]||R0=1000 [Ω]|
Interesting facts about PT 1000
The term Pt1000 resistance thermometer stands for numerous types – from single to double Pt1000. With the double Pt1000, two Pt1000 sensors are installed next to each other. This type of construction of Pt1000 temperature sensors is used where two signals have to be processed. The signal of the first Pt1000 thermometer is used for the control and that of the second Pt1000 thermometer for the display.
In addition, there is an accuracy class in which a distinction is made between Pt1000 classes A, B and AA. The latter is often referred to as 1/3 DIN.
The range is complemented by the Pt1000 sensors, which have a thread. These are also called screw-in Pt1000 or screw-in resistance thermometers Pt1000.
There is also the Pt1000 surface sensor, which measures the surface temperature with the aid of a Pt-1000. Since these sensors are often located in a round installation space in practice, the measurement results are usually not sufficiently accurate. In order to counteract this deficit, special Pt1000 surface sensors are manufactured in which the Pt wire is on a so-called Kapton film (a high-quality polyimide film) and can therefore be better adapted to the curves. This means that significantly better measurement results are achieved. The disadvantage of this solution, however, is that the costs of these Pt1000 sensors are several times over.
Another group of Pt1000 temperature sensors is one of the sensors known as Pt1000 jacket resistance thermometers. The Pt1000 temperature sensor is built into a mineral-insulated cable and tightly welded in the front area. The decisive advantage for this Pt1000 temperature sensor is the possibility of bending the cable behind the Pt 1000 temperature sensor, but still being able to build in a rigid object.
The output signal generated by a Pt1000 thermometer can, among other things, be connected to a PLC. A Pt1000 transmitter is required for this, which then outputs a signal of 4–20 mA or, in the case of a Pt1000 transmitter, 0-10V.
Each Pt 1000 sensor can be extended with a plug – Lemo plugs or M12 plugs as well as thermocouple plugs with Cu-Cu contacts are ideally suited for this. Special, “real” Pt1000 plugs are not required or are not available on the market.
By the way: What is not available, but is requested again and again, is a Pt1000 thermocouple or a Pt1000 thermocouple. These are two different measurement methods that are “linguistically” combined with one another. The method of a Pt1000 thermocouple and that of a thermocouple, which, in contrast to the Pt1000 resistance thermometer, cannot show any indication due to a change in resistance, but only builds up a thermal voltage.
The Pt1000 resistance thermometers from Therma Thermofühler GmbH set standards when it comes to quality, i.e. absolute precision and constant longevity. But these sensors also have a very good price-performance ratio.
In order to meet the professional requirements of our customers, they receive our Pt1000 temperature sensors in our online shop not only in different classes (B, A, AA or 1/3 DIN) and with different element and connection cable lengths, but also in all available circuit types (2-wire technology, 3-wire technology, 4-wire technology). Of course, we also offer our customers various connections (free ends, Lemo plugs or couplings) as well as cable types / cable materials (Teflon, glass fiber).
With our own development and production, we also have the opportunity to work out an individual solution for Pt1000 resistance thermometers. No matter whether for small quantities or specialized one-offs. And that at the usual low cost.