Pt1000 Probes

Pt1000 sensors are generally pretty accurate. The resistance values and accuracy classes are defined in DIN EN 60751 and IEC 751. Class AA is the one with the highest accuracy, class C the one with the lowest.

However, the accuracy of an individual sensor depends not only on the accuracy class of the measuring element, but also crucially on the cable length and the cable configuration (2-, 3- or 4-wire circuit) as well as the measuring current. The devil is in the details. Our experts are happy to help you choose the right temperature sensor!

The Pt1000 RTD has 10 times the resistance of a Pt100. It therefore has a significantly higher resolution. In addition, due to the higher base resistance, the unwanted resistance from lead wires adds less distortion than with a Pt100. This means that with cable lengths of up to 5 metres, you can stick to a simple 2-wire circuit.

On the other hand, the power loss of the Pt1000 is higher for the same measuring current. Therefore, you should apply a measuring current <0.1mA for high accuracy requirements in order to minimise the self-heating of the Pt1000 measuring element.

Due to its higher resistance, the Pt1000 is less sensitive to distortions from lead wire resistance than the Pt100. The resulting measurement error amounts to about 0.04 Kelvin per metre of cable length. With a Pt1000, we recommend that you use a 3- or 4-wire circuit with cables longer than 5m.

Alternatively, you can use a transmitter as close as possible to the sensor or directly use a temperature sensor with 0-10V/4-20mA output signal.

The output signal of a Pt1000 is relatively weak and therefore sensitive to interference. Amplification or conversion of the signal to a more robust one such as 0-10V or 4-20mA is therefore often recommended, particularly when using long connection cables. Our integrated transmitter also compensates for the measuring error and thus improves the accuracy.

You need a digital output signal? Take a look at our Modbus temperature sensor series!

Download your resistance tables now!

Regarding the response time of a sensor, the following rule of thumb applies: If you double the diameter, you quadruple the response time. So choose the diameter wisely!

As with all temperature sensors, the immersion length should be at least 5x the diameter of the sensor to avoid thermal bridges.