Factors affecting the accuracy of infrared thermometers

What are the factors that affect the measurement accuracy of infrared thermometers?

1. Measuring angles

To ensure accurate measurement, the instrument should try to measure along the normal direction of the surface of the object being measured (perpendicular to the surface of the target being measured).

If it cannot be guaranteed to be in the normal direction, measurements should also be taken within a 45 ° angle to the normal direction, otherwise the instrument display value will be lower.

2. Environmental temperature

The instrument should be used strictly according to the environmental temperature indicated by the instrument's technical specifications. If the measurement error of the instrument exceeds this range, it will increase or even be damaged.

When the ambient temperature is high, air-cooled, water-cooled devices or thermal protective sleeves can be used, which can enable the instrument to operate normally in environments up to 200 ℃.

When using a handheld thermometer from one environment to another with a significant temperature difference, it will temporarily reduce the accuracy of the instrument, in order to obtain ideal measurement results;

The instrument should be left on the work site for a period of time (recommended at least 30 minutes) to achieve equilibrium between the instrument temperature and the ambient temperature before use.

3. Air quality

Smoke, dust, and other pollutants in the air, as well as unclean lenses, can prevent the instrument from receiving sufficient infrared energy to meet measurement accuracy, resulting in increased measurement errors.

Therefore, it is important to keep the lens clean regularly, as an air blower helps to prevent contamination of the lens.

4. Electromagnetic interference

The instrument should be kept as far away from potential sources of electrical interference as possible, such as electric equipment with large load changes. The output and input connections of online instruments use shielded wires and ensure that the shielded wires are well grounded.

In strong interference environments, using external protective conduits is better for rigid conduits than flexible conduits. Do not introduce the AC power supply of other devices into the same conduit.

5. Environmental radiation

When there are other objects, light sources, or solar radiation with higher temperatures around the measured target, these radiation will directly or indirectly enter the measurement optical path, causing measurement errors.

In order to overcome the impact of environmental radiation, the first step is to avoid direct entry of environmental radiation into the optical path. The measured target should be filled with the instrument's field of view as much as possible. For indirect interference from environmental radiation, occlusion can be used to eliminate it.

6. Field of view and target size

Ensure that the target enters the instrument measurement field of view.

The smaller the goal, the closer it should be. In actual measurement, in order to reduce errors, the size of the target should be more than twice the size of the field of view spot.