Fluke 61 FE 61 Users Manual - Page 6

English How to Accurately Measure Temperature Locating a Hot Spot To find a hot spot aim the thermometer outside the area of interest, then scan across with an up and down motion until you locate the hot spot. Field of View Make sure that the target is larger than the unit's spot size. The smaller the target, the closer you should be to it. When accuracy is critical, make sure the target is at least twice as large as the spot size. Distance & Spot Size Yes No As the distance (D) from the object increases, the spot size (S) of the area measured by the unit becomes larger. D8 3"@ 24" 2"@ 16" 1"@ 8" 75 @ 600mm 50 @ 400mm 25 @ 200mm Reminders s Not recommended for use in measuring shiny or polished metal surfaces (stainless steel, aluminum, etc.). See Emissivity. s The unit cannot measure through transparent surfaces such as glass. It will measure the surface temperature of the glass instead. s Steam, dust, smoke, etc., can prevent accurate measurement by obstructing the unit's optics. 4