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Accurate infrared temperature monitoring improves product quality and increases productivity

Infrared (IR) sensors are non-contact temperature measuring devices that detect infrared radiation from the surface of all objects and calculate it to relevant temperature readings. 

Download the Principles and Benefits of IR Temperature Measurement to learn more about these effective thermometers that take temperature measurements in just fraction of a second without touching the object.

Temperature plays an important role as an indicator of the condition of a product or piece of machinery, both in manufacturing and in quality control. Downtimes are decreased since the manufacturing processes can proceed without interruption and under optimal conditions.

Benefits of Noncontact IR Temperature Measurement


  • It is fast (in the ms range) – saving time and allowing for more measurements and data accumulation.
  • It facilitates measurement of moving targets i.e. conveyor processes.
  • Measurements can be taken of hazardous or physically inaccessible objects i.e. high-voltage parts or large measurement distances.
  • Measurements of high temperatures (above 1300°C/2375°F) present no problems. Contact thermometers often cannot be used in such conditions.
  • There is no interference as no energy is lost from the target.
  • Noncontact temperature measurement is wearfree – there is no risk of contamination and no mechanical effect on the surface of the object.

Infrared technology has been utilized successfully in industry for decades, but new developments have reduced costs, increased reliability, and resulted in smaller, noncontact infrared measurement devices.

Distance to Target (Spot) Ratio

The optical system of an infrared sensor collects the infrared energy from a circular measurement spot and focuses it on the detector. Optical resolution is defined by the ratio of the distance from the instrument to the object, compared to the size of the spot being measured (D:S ratio). The larger the ratio number the better the instrument's resolution, and the smaller the spot size that can be measured from greater distance. A recent innovation in infrared optics is the addition of a Close Focus feature, which provides accurate measurement of small target areas without including unwanted background temperatures.


Make sure that the target is larger than the spot size the unit is measuring. The smaller the target, the closer you should be to it. When accuracy is critical make sure that the target is at least twice as large as the spot size.

Environmental Conditions

Watch for environmental conditions in the working area. Steam, dust, smoke, etc., can prevent accurate measurement by obstructing the unit's optics. Noise, electromagnetic fields, or vibration are other conditions that should also be considered before installation begins. A protective housing, air purging and/or water cooling can protect the sensor and ensure accurate measurements. For that reason some of our products, such as Thermalert and Marathon Series sensors, include air purging.

Ambient Temperatures

If the thermometer is exposed to abrupt ambient temperature differences of 20 degrees or more, allow it to adjust to the new ambient temperature for at least 20 minutes. Ircon sensors are specified for performance within certain ambient temperature ranges. For high ambient temperatures, Ircon offers air cooling and water cooling options as well as accessories.


Emissivity is the measure of an object's ability to emit infrared energy. Emitted energy indicates the temperature of the object. Emissivity can have a value from 0 (shiny mirror) to 1.0 (blackbody). Learn more about emissivity and emissivity values for various common materials and metals.