IR Thermometer Calibration

1. Scope of procedure

Unit Under Test Characteristics	Performance Range	Performance method
Temperature	(-10 ÷ 500)°C	Comparison to Blackbody.

2. Equipment, standard requirements

– Blackbody: FLUKE, OMEGA or equivalent, accuracy better than 3 times UUT.

– Measuring tape.

3. Environment conditions

Temperature: (20 ÷ 28)°C

Relative Humidity: (30 ÷ 70)%RH

4. Preparation

– Visually inspect the Unit Under Test (UUT) for obvious damage that may affect accuracy and/or operation and note any observations.
– Connect UUT to suitable power and turn on.
– Turn on Blackbody, allow warm-up at least 10 minutes or follow manufacturer’s instructions.
– Technician must be familiar with calibration techniques, content of this calibration procedure and the operator manual of the UUT being calibrated, and the generator being used.

5. Perform

– Almost infrared thermometer has default emissivity 0.95. Some IR device such as thermal imager, thermal camera can adjust other emissivity. In this case, emissivity shall be set at 0.95 also.
– Follow user guide of Blackbody, set emissivity equal to 0.95, same with UUT.
– Base on UUT Distance to Spot ratio (D:S), use measuring tape to set the distance between Blackbody emitting surface and the UUT, that required for calibration process.

– Perform at least 5 points evenly distributed across the UUT range. Other test points may follow customer’s requirements.
– Begin at the lowest calibration point, example -10oC first, then increase for higher points.
– Set the Blackbody for the first calibration point and allow sufficient time to stabilize.
– Waiting for stable reading on UUT and the Blackbody, record repeat values.
– Repeat for remain test points.
– Calibration now completed, set and allow temperature of Blackbody near to normal room temperature.
– Turn off Blackbody and UUT, take out and secure all equipment.

6. Tolerance

– Tolerance given by the customer will be applied for all measurement, unless otherwise provisions.
– If the customer does not required, the specifications of manufacturer or other source of reference will be used.
– If not, the tolerance ±2oC or ±2%reading of UUT will be applied.

Nguyen Thuy