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PT100 vs. PT1000: A Direct Comparison for Industrial and Laboratory Applications
Resistance thermometers are among the most precise sensors in industrial temperature measurement. Anyone selecting a new sensor sooner or later faces the question of which platinum resistance is the right one for the application. This article shows the technical differences and provides a clear selection guide for everyday practice.
Pt100 vs Pt1000 in a Direct Comparison for Industry and Laboratory
Anyone selecting a platinum resistance for industrial temperature measurement quickly arrives at the comparison Pt100 vs Pt1000. Both sensor types measure on the same principle and follow the same standard, but the tenfold higher nominal resistance of the Pt1000 has tangible consequences for the evaluation device, the wiring layout and self-heating. In the following, we show how Pt100 and Pt1000 differ technically, in which applications which sensor fits better, and what role tolerance class and wiring configuration play in accuracy. The aim is a clear practical guide that makes the choice easier for buyers, designers and operations engineers in just a few minutes.
Understanding the Working Principle of Resistance Thermometers
Resistance thermometers measure temperature via the change in electrical resistance of a platinum conductor. As temperature rises, the resistance increases almost linearly, which allows precise evaluation across a wide range. Unlike a thermocouple, the resistance thermometer does not produce a thermal EMF; instead, it is supplied with a constant measurement current and the resulting voltage drop is evaluated.
Pt100 and Pt1000 do not differ in the measuring principle, only in the nominal resistance at 0 °C. Both sensor types are standardised under the same DIN EN 60751 and can reach the same tolerance classes. Much of what is known about the classic Pt100 therefore applies one to one to the Pt1000 as well. At Therma, we have been manufacturing both sensor types in our own production in Lindlar since 1991 and supply them as part of our resistance thermometers in numerous form factors.
Why Platinum as the Material?
For decades, platinum has established itself as the standard material for Pt sensors. The metal shows high long-term stability, almost no chemical reactivity and a well-reproducible characteristic curve even after many temperature cycles. These very properties are decisive in industrial applications, because a sensor often has to perform its task for years without drift. Other metals such as nickel or copper do appear in special sensors but cover neither the wide temperature range nor the stability of platinum.
Pt100 in Detail Construction and Standardisation
The Pt100 takes its name from the nominal resistance of 100 ohms at 0 °C. As the temperature rises, the resistance increases by about 0.385 ohms per kelvin, which is referred to as the temperature coefficient alpha of 3850 ppm/K. At 100 °C, the resistance is therefore around 138.5 ohms and at 200 °C about 175.9 ohms.
Nominal Resistance 100 Ohms and Temperature Coefficient
According to DIN EN 60751, the Pt100 covers a measuring range from minus 200 °C to plus 850 °C. It is therefore suitable both for cryogenic applications and for classic industrial processes with high temperatures. In practice, the Pt100 is supplied in numerous form factors, including sheathed, sheathed-tube, screw-in and surface designs.
Form factors differ primarily in protection tube, connection type and method of mounting. A sheathed Pt100, for example, suits flexible installation in bores, while a screw-in Pt100 with thread is fitted directly into an installation. The choice of form factor affects lead time and the need for special production but has no influence on the electrical behaviour of the Pt characteristic curve itself.
Pt1000 in Detail Higher Resistance for More Resolution
For the Pt1000, the nominal resistance at 0 °C is 1000 ohms, exactly ten times that of the Pt100. The temperature coefficient also remains identical at 3850 ppm/K; only the absolute resistance values shift upwards by a factor of ten. At 100 °C, a Pt1000 therefore reads around 1385 ohms.
When the Pt1000 Came Into Being
The Pt1000 emerged with the demand for higher resolution in modern device electronics. While analogue evaluation devices were mostly designed for the Pt100, digital input stages with high input impedance benefit from the tenfold larger signal swing. If you read out a Pt1000 in a PLC or a microcontroller, you obtain a tenfold finer temperature resolution than with a Pt100 at the same input-stage resolution.
For a Pt1000 to reach the same accuracy as a Pt100, the same tolerance classes according to DIN EN 60751 apply. Pt1000 sensors are manufactured in the same form factors as Pt100, that is, as sheathed, screw-in or surface variants. Selection therefore follows the same criteria as for the classic Pt100, with the difference of evaluation-device compatibility.
Pt100 vs Pt1000 Differences at a Glance
In a direct comparison, the difference between Pt100 and Pt1000 shows above all in sensitivity to lead resistance and self-heating. Both sensors deliver the same accuracy, but their behaviour in the measurement chain differs noticeably.
| Criterion | Pt100 | Pt1000 |
|---|---|---|
| Nominal resistance at 0 °C | 100 ohms | 1000 ohms |
| Resistance at 100 °C | 138.5 ohms | 1385 ohms |
| Slope (alpha) | 3850 ppm/K | 3850 ppm/K |
| Typical measurement current | 1 mA | 0.1 mA |
| Self-heating | higher | lower |
| Influence of lead resistance | high | low |
| Typical use | industry, long cables | device electronics, short cables |
What 10x Higher Resistance Means in Practice
The tenfold higher resistance of the Pt1000 reduces the proportional influence of the lead resistance on the measured value. Where a Pt100 shows about 0.4 kelvin error per metre of cable, the Pt1000 under otherwise identical conditions only shows around 0.04 kelvin error per metre. Precisely for this reason, a Pt1000 can safely be operated in a 2-wire connection in many device applications, whereas the Pt100 there requires a 3-wire or 4-wire connection. Both types are made by hand at our facility in line with ISO 9001 and undergo the same quality controls.
When the Pt100 Is the Better Choice
The Pt100 is the right choice as soon as long cables, high temperatures or existing evaluation devices with a Pt100 input are involved. In classic industrial systems, the Pt100 is still the standard, especially in combination with a 3-wire or 4-wire connection on a transducer or process control system.
Typical Industries for the Pt100
In daily practice, you find the Pt100 above all in the following applications:
- Plant engineering and mechanical engineering with long cable runs
- Power plants and energy generation with high-temperature processes
- Chemical and petrochemical production
- Food and pharmaceutical industry with hygienic-design requirements
- High-temperature furnaces above 600 °C up to annealing applications
- Cryogenics with special sensors down to minus 200 °C
For high-temperature and industrial applications, sheathed-tube resistance thermometers are often used; their protection tube shields the sensor from pressure, mechanical load and aggressive media. The Pt100 scores here with a wide selection of form factors and easy integration into existing measuring and control technology.
When the Pt1000 Brings Clear Advantages
The Pt1000 plays out its strengths wherever the evaluation device is compact, battery-powered or digital. The tenfold higher resistance ensures that a given measurement current produces a noticeably higher voltage, which directly improves the resolution of the input stage.
Pt1000 in HVAC and IoT Sensing
The Pt1000 is particularly suitable for the following applications:
- Building services and HVAC with short cable runs
- Heating control and underfloor temperature sensors
- Mobile data loggers and battery-powered measuring devices
- Internal device electronics with a minimal current budget
- IoT sensors with low bandwidth and a compact form factor
The lower measurement current of typically 0.1 milliampere reduces the self-heating of the sensor and extends battery life. We supply Pt1000 sensors in all common form factors and on request support you in choosing the right input stage for your device electronics. In new developments in particular, taking a closer look at the Pt1000 as the standard pays off, because it noticeably simplifies design work on the evaluation side.
Tolerance Classes and Accuracy According to DIN EN 60751
The accuracy of a Pt sensor is specified in tolerance classes according to DIN EN 60751. These classes apply regardless of the nominal resistance, and therefore equally to Pt100 and Pt1000. The standard defines four classes, each of which has its own tolerance formula.
Class AA offers the highest precision, followed by class A, class B as the common industry standard and class C for less demanding applications. The tolerance grows with absolute temperature, because the formula combines a fixed share and a temperature-dependent share. Class A, for example, allows a tolerance of 0.15 kelvin plus 0.002 times the absolute value of the temperature in degrees Celsius.
Example Calculation Class A at 100 °C
If you insert 100 °C into the formula, the result is a maximum deviation of 0.15 plus 0.002 times 100, that is 0.35 kelvin. The same calculation for 0 °C yields only 0.15 kelvin tolerance. Anyone needing higher accuracy reaches for class AA with a halved fixed share. The class does not influence the resolution of the display but the maximum error of the sensor itself, and applies equally to Pt100 and Pt1000.
2-Wire, 3-Wire and 4-Wire Connection Compared
The wiring configuration determines how strongly the lead resistance between sensor and evaluation device distorts the measured value. With the Pt100, this effect is much more critical than with the Pt1000, because the sensor resistance itself is smaller.
In the 2-wire connection, the lead resistance is added directly to the sensor resistance. With the Pt100, this produces about 0.4 kelvin error per metre of copper cable with a cross-section of 0.5 square millimetres. The 3-wire connection compensates for the lead resistance almost completely, provided the three conductors have the same cross-section. It has therefore established itself as the industry standard for Pt100. The 4-wire connection eliminates the cable influence completely and is used above all in the laboratory and in precision measurements.
How the Higher Pt1000 Resistance Reduces Cable Influence
With the Pt1000, the lead resistance carries proportionally ten times less weight. A Pt1000 can therefore easily be operated in a 2-wire connection with a short cable in many applications. If you would like to go deeper into wiring technology, you will find further content on the Pt100, the Pt1000 and the wiring configurations in our basics of temperature measurement.
Practical Guide for Choosing Pt100 or Pt1000
If you are facing the question of Pt100 or Pt1000, you can narrow down the choice very quickly with five guiding questions. In practice, a single criterion rarely decides; rather, it is the interplay of evaluation device, cable length and installation space.
Quick Decision Aid in 5 Questions
The following checklist has proven itself in consultation:
- Which input stage does the evaluation device have, and which sensor type is foreseen?
- How long is the cable between sensor and evaluation unit?
- Which tolerance class does the application require?
- Which temperature range is covered, especially in the high-temperature or cryogenic range?
- Which form factor fits mechanically into the intended installation location?
In most industrial applications with long cables and standard processes, the answer leads to the Pt100. With compact device electronics, short cables and battery-powered devices, the Pt1000 takes the lead. In practice, users often reach for a standard resistance thermometer, which is supplied in both variants alike.
We regularly advise buyers and designers on selection and supply both variants from stock with a regular delivery time of one week. For special requests, a sketch or a STEP file is enough. Speak to us via the contact form or send a quote request if you need a concrete recommendation for your application.
Conclusion on the Difference Between Pt100 and Pt1000
The comparison Pt100 vs Pt1000 is less a question of better or worse than a question of intended use. The Pt100 remains the standard in industrial measurement and control chains with long cables and existing Pt100 infrastructure. The Pt1000 scores wherever compact device electronics, battery-powered measurement technology or short cables set the tone. Both sensors share standard, tolerance classes and form factors, so that the decision in many cases is shaped by the evaluation side and not by the sensor itself. For a confident selection, the five guiding questions from the practical guide help; the rest is a brief enquiry to expert advice.
