Pt1000 Temperature Sensors

One of the main features of a Pt1000 RTD temperature sensor is the relatively high nominal resistance and fundamental interval which means that the resistance of any extension cable is generally negligible compared to the sensor. This permits the use of a simple 2 wire measuring circuit in almost all applications. Pt1000 temperature probes with a 5 metre cable would have an additional error of less than 0.1°C. For a Pt100 this would be ten times worse, perhaps 1°C depending on the cable used.

For this reason, the vast majority of Pt1000 RTDs are supplied with a 2 wire measurement circuit as this helps to minimise the cost of the finished probe whilst also ensuring simplicity of the measuring system.

It is possible to use 3 and 4 wire connections, but this is less common and there is generally no technical reason to adopt these systems with a Pt1000.

How accurate are Pt1000 temperature sensors? –
The accuracy of a Pt1000 temperature probe is determined by the sensing element chosen. We are generally limited to using flat film detectors in the construction of Pt1000 temperature probes and therefore this limits the range of accuracies available.

The three tolerance bands available are:-
Class B +/-0.3°C at 0°C
Class A +/-0.15°C at 0°C
1/3 DIN +/-0.10°C at 0°C
Note that for the equivalent tolerance band, Pt1000 sensors are as accurate as Pt100’s.

Flat film sensing elements are extremely cost effective and there is not a large price differential between the different tolerance bands. Process Parameters holds stock of all three.

What is the temperature range for Pt1000’s? –
As with accuracy, the temperature range of the sensor is limited by the type of sensing element used in the construction of the temperature probe. Flat film detectors are extremely versatile and can withstand the following temperatures:-

Class B -70 to +500°C

Class A -50 to +300°C

1/3 DIN 0 to +150°C

Note that in all cases the limitation is the ability of the detector to remain in tolerance rather than being an absolute temperature limit. For example, it is perfectly possible for a 1/3 DIN sensor to operate below 0°C but it may not remain in tolerance. In this case you would revert to the next tolerance band.

The construction of a temperature probe and materials used determine its suitability for a particular application. The same features apply for Pt1000 as for other temperature sensors such as Pt100, Thermocouples or Thermistors.

The sensing element itself is joined to an extension wire or cable in order to provide the resistance output to a point where it is measurable. Process Parameters always weld extension wires to the sensing elements as this provides a higher temperature join that soldering and gives the lowest possible resistance between the cable and detector. The sensor is then potted into the housing using various materials depending on the temperature range required and the other environmental conditions. We can provide constructions for very low temperatures down to -200°C all the way up to 500°C. In general, sensors are either terminated in a cable, a terminal housing or a connector. Process Parameters offers all these options.