D:s ratio – Velleman DVM77N User Manual

Page 5

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DVM77N

VELLEMAN

5

How to Measure the Ambient Temperature


Press the SCAN button. Press the Tamb button to select the ambient temperature measurement mode. Press the SCAN button to measure.

Read the measured temperature value from the LCD display. Release the SCAN button. The thermometer will automatically power off after
20 seconds. To measure again, press the Tamb button again and restart the ambient temperature measurement procedure.


NOTE: The measurement accuracy will be affected when measuring the temperature of reflecting objects. Apply some black tape to the

object and wait for the tape to adopt the object’s surface temperature before measuring.


How to Select the Measuring Unit


Remove the batteries and set the measuring unit switch to the desired unit.

8. D:S Ratio


The thermometer has a visual angle and a visual spot size. Make sure the target is larger than the unit’s visual spot size. The smaller the

target, the closer you should be to it. The relationship between distance and spot size is 6:1.

Units in mm, D = distance, S = spot size

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