
-2-
1.For reliable measurements it is necessary to use
reflective markers. o apply the reflective markers,
wait until the object to be measured has come to a
standstill.
2.he ideal distance to the measurement object is
between 4” to 16”. During the measurement, always
aim at the reflective marker from an angle of
approximately 30°. his avoids multiple reflections
from the surface.
3. If no reflective marker can be attached, it must be
checked whether the reflective properties of a
reflective point on the measurement object are
sufficient for rpm measurement. In this case, aim at
the measurement object from the vertical, and check
whether a value is displayed. If the measurement
object displays several reflections per revolution, the
number of ventilator vanes must be set (e.g.
reflective ventilator with 5 vanes) in order to obtain
correct rpm measurements.