Choosing an Infrared Pyrometer.

8 Important Things You Need to Know.

The material you want to measure and its surface finish.

This is extremely important to be able to take a reliable temperature measurement and will have a direct impact on the sensor chosen and the emissivity setting you use. Remember that metallic parts are potentially tricky to measure but with careful sensor selection we can overcome these issues. Special sensors are also available to accurately measure the temperature of thin film plastics, glass and through flames. Also don’t forget to choose a sensor with adjustable emissivity. All Optris sensors have this facility but you may find that other manufacturers do not.

The size of the object that you are measuring.

When using an infrared pyrometer the size of the object being measured is necessary so the correct sensor can be selected. The measuring spot for the sensor needs to be positioned completely on the part. We can offer plenty of choice when it comes to selecting a sensor with a variety of optical resolutions available including spot size down to less than 1mm in some cases.

Ambient temperature.

Is the sensor you have chosen suitable for the operating environment it will be working in? If not, it is possible to cool or heat the sensor to ensure it meets the operating parameters.

Dust, dirt and humidity.

Is there a high possibility of debris or moisture settling on the lens of your sensor? If so, this will almost certainly lead to poor quality measurements. It is possible to fit air purge collars to our sensors in order to prevent this.

How will you aim the sensor?

For many applications it is easy to aim the sensor as the parts are large enough that it is almost impossible to miss. However, when considering smaller parts and when measuring through gaps in machinery aiming will be important. We can offer laser aiming accessories and our high performance series have an innovative dual laser aiming system built in that gives spot size and position.

Are you measuring through a window?

If so then you need to consider two things. First of all will the window transmit infrared light in the part of the spectrum you need for your sensor? If so, you will also need to consider losses. Placing a window in front of your sensor is a bit like wearing sunglasses, some energy gets lost. All you need to do is compensate for this loss by entering a Transmissivity setting in your sensor’s software.

Sensor output signal.

You will obviously need to know what signal you need from your sensor in order for it to operate with your instrumentation. Fortunately, Optris sensors have a multitude of possibilities available and many are configurable on the unit itself.

Speed of response.

By their very nature infrared temperature sensors are massively quicker than contact probes such as thermocouples or RTDs. However in some applications speed of response is extremely important. Typically an Optris sensor will have a response time of less than 100 milliseconds but we offer products with response times as fast as 1 millisecond.


This article is intended as a guide and does not replace our own free technical assistance which is always readily available.

If you would like additional assistance, we can help you. Please contact us and we would be glad to discuss your application and help with your product selection.