Extech Instruments 42512 User Manual page 7

1. The object under test should be larger than the spot (target) size calculated by the field
of view diagram (printed on the side of the meter and in this guide).
2. Before measuring, be sure to clean surfaces that are covered with frost, oil, grime, etc.
3. If an object's surface is highly reflective, apply masking tape or flat black paint to the
surface before measuring. Allow time for the paint or tape to adjust to the temperature
of the surface it is covering.
4. Measurements through transparent surfaces such as glass may not be accurate.
5. Steam, dust, smoke, etc. can obscure measurements.
6. The meter automatically compensates for deviations in ambient temperature. However,
it can take up to 30 minutes for the meter to adjust to extremely wide changes.
7. To find a hot spot, aim the meter outside the area of interest then scan across (in an up
and down or side to side motion) until the hot spot is located.
The meter's field of view is 30:1. For example, if the meter is 75cm from the target (spot),
the diameter of the target must be greater than 2.5cm. Other distances are shown in the
field of view diagram. Measurements should normally be made as close as possible to the
device under test. The meter can measure from moderate distances but the measurement
may be affected by external sources of light. In addition, the spot size may be so large that
it encompasses surface areas not intended to be measured.
7 42512-EU V7.1 02/09