Fluke 561 [10/16] Users manual

561

Users Manual

How the Thermometer Works

Infrared thermometers measure the surface temperature of an opaque object. The

Thermometer’s optics sense infrared energy, which is collected and focused onto a detector.

The Thermometer’s electronics then translate the information into a displayed temperature

reading which appears on the display. The laser is used for aiming purposes only.

Operating the Thermometer

The Thermometer turns on when you press the trigger. The Thermometer turns off when no

activity is detected for 7 seconds.

To measure temperature, aim the Thermometer at the target, pull and hold the trigger. Release

the trigger to hold a temperature reading.

Be sure to consider distance-to-spot size ratio and field of view. The laser is used for aiming

only.

Locating a Hot or Cold Spot

To find a hot or cold spot, aim the Thermometer outside the target area. Then, slowly scan

across the area with an up and down motion until you locate the hot or cold spot. See Figure 4.

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Figure 4. Locating a Hot or Cold Spot

Distance and Spot Size

As the distance (D) from the target being measured increases, the spot size (S) of the area

measured by the unit becomes larger. The spot sizes indicates 90 % encircled energy. The

maximum D:S is obtained when the Thermometer is 900 mm (36 in) from the target resulting in

a spot size of 75 mm (3 in). See Figure 5.