Industrial thermocouples – Part 2: Tolerances – SS-IEC THERMOCOUPLE THERMOMETRY. Thermocouple Accuracies. Tolerance classes for thermocouples to IEC Fe-Con (J). Class 1. IEC Reference, Edition, Title / Details. ASD-STAN prEN P1. Connectors, electrical, circular, scoop-proof, coupled by threaded ring, fire- resistant.
|Published (Last):||7 June 2015|
|PDF File Size:||17.83 Mb|
|ePub File Size:||15.84 Mb|
|Price:||Free* [*Free Regsitration Required]|
Selecting the right type of temperature sensor depends on your measuring task. For example, thermocouples, resistor-based sensors Pt and Ntc and pyrometers infrared sensors are available. Select the temperature sensor that suits your measuring task according to the criteria below: Thermocouples consist of two spot-welded wires of different metals or alloys.
The thermoelectric effect at the contact surface is used to measure temperatures. A relatively small thermoelectric voltage is caused, which depends on the temperature difference between the measuring point and the connecting terminals.
The accuracy class is ied for every thermocouple sensor.
Basics of temperature measurement
The accuracy applies within the above specified range of validity. The operative range is specified for every sensor — depending on its construction. These values refer to the sensor tip. Additionally, the operative ranges of the connecting cable and the transition sleeve or similar have to be considered.
Heat-resistant cables are also available on request. Various types of thermocouples are available; these can be distinguished in terms of their temperature range, sensitivity, and in particular their compatibility with the test substance. The most popular thermocouple is the NiCr-Ni type K.
Connecting cable with thermal line stranded wire There is no adverse temperature effect at the juncture from measuring element to cable.
With immediate effect, the sensor connecting cables for many sensor types will use a new thermal line stranded wire, thermal line class 2 instead of the conventional compensation line.
For just a few sensor types and extension cables a compensation line will continue to be used as previously.
Temperature measurement – Ahlborn Meß- und Regelungstechnik GmbH
The compensation lines generally comply with Class 2 as per DIN When measuring the temperature the increase in resistance at increasing temperatures is utilised at the Pt sensors. The measuring resistor is fed with a constant current and the voltage drop at the resistor is iex as a function of the temperature.
Due to the small resistance variation 0. Several accuracy classes are ice for the Pt sensor. The accuracy class is specified for every Pt sensor. The accuracy applies within in the above specified range of validity. Heat-resistant cables are available on request. Measuring range PT resolution 0. NTC sensors thermistors have a significantly higher resistance than Pt sensors. When measuring temperatures their negative temperature coefficient is utilised, i. The accuracy of the sensor element is manufacturer-specific.
Processing, crossing points, terminal points and connecting cable influence the accuracy of the temperature sensor. The following accuracy is specified for the NTC temperature sensor with a cable length of 2 meters:. Additionally, the operative ranges of the connecting cable and the transition sleeve or the like have to be considered. The construction variants of temperature sensors are as many and diverse as the measuring tasks. T max is the maximum operating temperature of the sensor tip.
The specified T 90 times refer to measuring operations in a moving liquid. The temperature sensors listed are also available, on request, with other lengths and diameters.
Surface sensors with flat measuring iex – For measurements on good heat conductors, on even and plain surfaces. Surface sensor with spring-type thermocouple band – For quick measurements, also on non-plain surfaces.
Immersion probes – For measurements in liquids, as well as powdery substances, air and gases. Sensors with heat-resistant measuring tip – For measurements at extremely 584–2 temperatures. Sensor with penetrating tip – For measurements in plastic and pasty substances.
Sword probe – For measurements in paper, cardboard and textile stacks. Transducer with free sensor – For measurements in air and gases. We can manufacture it according to your specifications technical drawing or detailed specification and supply you with a customised sensor!
Thus, the measuring accuracy can be significantly increased. The adjustment can be realized in 2 points zero, gradient or in over 30 points as multi-point adjustment. Thanks to this procedure the slightest eic are archived on the calibrated temperature points. An increased accuracy can be achieved by a multi-point adjustment of the sensor during the 584–2 process.
Industrial thermocouples – Part 2: Tolerances
Linearization of the Pt characteristic with accurate calculation method. Increased accuracy for calibrated sensors thanks to multi-point adjustment of the 58-42 sensor.
The high resolution of 0. Linearization of the NTC characteristic according to Galway Steinhart with accurate calculation method. Increased accuracy thanks to multi-point adjustment of the NTC sensor during the calibration process. The linearization of the NTC characteristic is calculated accurately with the Galway Steinhart coefficient no approximation procedure.
Infrared sensors do not contact the device under test and they have very small time constants, but they depend on the emission grade. The larger the measuring range, the more universal the possible range of applications. Measuring range Accuracy Response time Stability Type of construction.
Thermocouples Thermocouples consist of two spot-welded wires of different metals or alloys. Connecting cable with thermal line stranded wire There is no adverse temperature effect at the juncture from measuring element to cable With immediate effect, iex sensor connecting cables for many sensor types will use a new thermal line stranded wire, thermal line class 2 instead of the conventional compensation line.
Resistor-Based Sensors Pt Sensors. Pt Sensors When measuring the temperature the increase in resistance at increasing temperatures is utilised at the Pt sensors. The following accuracy is specified for the NTC temperature sensor with a cable length of 2 meters: Accuracy of the NTC sensors: The temperature sensors listed are also available, on request, with other lengths and diameters Surface sensors with 5584-2 measuring tip – For measurements on good heat conductors, on even and plain surfaces.