VIBROTEST 60
Technical Data
_________________________________________________________________________________
© VTEST60E July 2013 V4.46ff
C102 853.002
Page 165 of 168
a)
Strong "noise" from the shaft surface
(irregular reflections due to striations or
surface irregularities) and the relatively
low voltage rise in the area of the refe-
rence mark cause
multiple triggering
.
b)
If the distance is
too large
, the amount
of light emitted is insufficient. This causes
insufficient rise of the output voltage and
thus
loss of reference
.
c)
If the distance is
too small
(saturation
of the receiving diode) or when ambient
light is too strong, the voltage rise of the
output signal might be drastically reduced
and thus
reference will be lost
as
mentioned under b.
d)
Foreign scattered light from artificial
light sources might cause
multiple trig-
gerin
.
e)
With correct conditions the signal level
in the area of the reference mark can be
clearly distinguished from that of the
surrounding area and thus supplies a
stable reference
.
Recommendations and corrective action:
The problems described above can safely be avoided by using
reflecting tape SCOTCHLITE GAIN RP 7610
(Manufacturer: 3M).
This tape has the following decisive characteristics:
•
Factor 1000 of Reflection compared with a white
surface.
The foil can thus be used as a white mark even on highly
shiny shaft surfaces.
•
Reflection of light in all directions.
This characteristic permits an inclined setup of the refe-
rence pickup. This helps absorption of a large amount of
reflected light whereas undesired reflections from the shaft
are very weak or have no effect at all.
Fig. 7 Output signal of the reference pickup
under different conditions
