Surface Mode Calibration
Surface Mode has a calibration setting that will allow you to change the surface temperature readout by ±3.6°F/±2°C. If you feel that the temperature is reading slightly high or low you have the ability to adjust for this discrepancy. To enter the calibration mode, confirm that you are in Surface Mode and press and hold the MODE key. Depending on the unit of measure the thermometer is set to, “32.0°F” or “0.0°C” will appear and begin flashing. Press the button to adjust the temperature. As the
button is pressed, the temperature will initially increase up to 35.6°F or 2°C and then change to 28.4° or -2°C before increasing again. If the thermometer is reading 1° low, you would enter calibration mode and set the temperature to 33° or 1°C to account for the 1° difference in temperature.
Note: The thermometer will remain in calibration mode for approximately 15 seconds. If you are unable to adjust the temperature within this time please repeat the process above. 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 is used to determine 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 DH7 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 DH7 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 DH7 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 object gets smaller the distance the thermometer is held from the target should decrease as well.
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Warning Messages and Indicators
• LLL – the object being measured is below the temperature range of the thermometer.
• HHH – the object being measured is above the temperature the range of the thermometer.
• LO – indicates that the batteries are low and need to be changed.
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