Surface Mode Calibration
Surface Mode has a calibration setting that will allow you to change the temperature readout by ±18°F/±10°C. If you feel that the temperature is reading slightly high or low you have the ability to adjust this. To enter the calibration mode, make sure that you are in Surface Mode and press and hold the SET button. “0.0°” will appear on screen and begin flashing. Press the UP or DOWN button to change the temperature in 1° increments. If the thermometer is reading 1° low, you would enter calibration mode and set the temperature to 1.0° to account for the 1° difference in temperature.
Note: The calibration will only affect the temperature readouts when in Surface Mode. It does not change anything in Probe Mode.
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Emissivity
Emissivity is the measure of an objects ability to emit infrared energy. This emitted energy indicates the temperature of the object. Emissivity can have a value from 0 to 1 with most organic, painted, and oxidized surfaces having an emissivity value close to 0.95. The DH8 has a fixed emissivity of 0.95. Objects with low emissivity (reflective surfaces) can be measured more accurately by placing a piece of black electrical tape over the surface and allowing it to reach the temperature of the surface underneath it.
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Distance to Spot Ratio
The DH8 measures surface temperature utilizing the distance to spot diameter ratio (D:S). This is the size of the area (“spot”) being measured as it relates to the distance of the thermometer from the spot. As the distance (D) between the thermometer and object increases, the spot size (S) of the area being measured will also increase. The DH8 has a D:S ratio of 5 to 1 so it will measure a 1 inch spot at a distance of 5 inches, a 2 inch spot at 10 inches, etc. For accurate readings make sure that the target is larger than the thermometers spot size. As the target gets smaller the distance from the target should decrease as well.
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Warning Messages and Troubleshooting
• LLL.L – the object being measured is below the temperature range of the thermometer or the probe is not plugged into the port in Probe Mode.
• HHH.H – the object being measured is above the temperature range of the thermometer.
• – indicates that the batteries are low and need to be changed.
• If the unit display freezes, remove the batteries for 5 seconds to reset.
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