General Tools and Instruments VR40 - Manual (Page 18)

To eliminate measurement error, the VR40 must be
moved close enough to the target so it is the only object
in the target area. The figure below illustrates
measurement of a motor’s temperature from the wrong
(top) and right (bottom) distance. For a motor with an
area of 1 ft
2 , the optimum measurement distance for
the 4:1 IRT in the VR40 would be 4 ft.
Note that when you release the IRT button after
measuring a surface temperature, the reading will be
held on the LCD for 20 seconds, until the Auto Power
Off (APO) function activates and powers off the
instrument. During this period of time, the
and
icons will appear at the upper left of the LCD. During
this interval, you can change the temperature unit of
the readout.
18
D:S=4:1