Here are listed the advantages and disadvantages of non-contact temperature measurement with stationary infrared pyrometers, portable infrared thermometers, infrared sensors and infrared temperature measuring devices.

Advantages:

• The method of non-contact temperature measurement via infrared is very low-wear for the measuring equipment compared to contacting NTC or Pt sensors.
• Very fast temperature measurement: the measurement result is available in less than 1 second.
• Very safe temperature measurement: when measuring very hot measurement objects, e.g. liquid metal in the casting process or electrically live measurement objects such as transformers, or aggressive materials, the non-contact temperature measurement is carried out from a safe distance from the measurement object.
• Very wide temperature measuring range: available e.g. 0-1000°C or 450-2000°C
• No damage to the measurement object during the measurement process, which is a great advantage for sensitive measurement objects such as in paper manufacturing or foil production.
• No temperature influence on the measured object by the sensor.
• Temperature measurement is also possible for very fast-moving measurement objects, e.g. on conveyor belts, cardboard bonding, adhesive application, coating processes.

Disadvantages:

• The emissivity of the object to be measured must be known, otherwise the measurement results may deviate significantly from the actual surface temperature. Especially when measuring the temperature of metals without contact, different emissivities at different temperatures make exact measurement difficult.
• The measured object must be exactly in the optical measuring field of the infrared pyrometer
  to avoid incorrect measurements.
• If there are visibility-impeding influences such as dust and smoke particles or vapour in the field of view between the pyrometer and the object to be measured, or if particles are deposited on the sensor lens, this affects the accuracy of the measurement result (exception: ratio pyrometer). However, this can be remedied by using air purge attachments for the sensor, which use compressed air to clean the sensor lens and keep it clean.
• Thermal radiation sources such as fan heaters, glow coils or radiant heaters in the production process influence the measurement result if the thermal interference radiation radiates into the optical measuring field of the infrared pyrometer
• Very rapidly changing ambient temperatures in a very wide temperature range can influence the measurement result if a certain sensor adjustment time is not observed. However, this influencing factor can be greatly reduced if a water heat sink or compressed air cooling on the sensor ensures a constant temperature of the sensor housing.