Leuze electronic GmbH + Co. KG
In der Braike 1 D-73277 Owen Tel. +49 (0) 7021 573-0
[email protected] • www.leuze.com
4.3
Adjusting sensitivity (Sens potentiometer)
If the edges can not be detected correctly using the presetting specified in section 4.1, it is possible to increase the detection rate by
adapting the sensitivity. Adjustment is performed using the
Sens
(sensitivity) potentiometer. Rotation to the left or right effects an incre-
ase/reduction of the sensitivity.
Medium sensitivity is wholly adequate for newspapers, magazines or similar objects. For extremely small edges or high sequential
speeds of edges, detection accuracy can be improved by increasing the sensitivity. Structured edges can lead to counting errors. These
counting errors can be avoided by reducing the sensitivity.
Fig. 6:
OPSL 775 - Setting sensitivity
4.4
Dynamic pulse adaptation (DPA program)
The dynamic pulse adaptation has already been activated at the factory and is signaled via the
DPA
LED. Actuate the
DPA
button for
> 50ms in standby mode to deactivate the program; the
DPA
LED extinguishes. Pressing the button again will return you to your original
position.
The current state is saved permanently.
Dynamic pulse adaptation is only suitable for relatively regular edge distances (example: printing of newspapers). The program adapts
the output pulse width permanently to the period directly following the object. The distance of the individual objects thus corresponds
to 100%. An output pulse corresponding to 50%, 25% or 12.5% of the period following the object is generated in correlation with the
setting of the
pulse width
(
) potentiometer (see fig. 7).
If the calculated output pulse width is greater than the measured object sequence time, the actual pulse is automatically shortened in its
duration. The output pulse is turned off no later than the rising pulse edge of the next detected edge. It is therefore not possible that the
electronics suppresses detected edges. Interference pulses are successfully suppressed by the internal hysteresis of the detector circuit.
Fig. 7:
OPSL 775 - Effect of dynamic pulse adaptation
Table 2
Attention!
The output pulse width can only be set to one of three stages: Maximum – Intermediate position – Minimum.
Position
Designation
Output pulse width T [%]
Maximum
max
50
Intermediate position
--
25
Minimum
min
12.5
Potentiometer position:
High:
High sensitivity
Medium:
Medium sensitivity
Low:
Low sensitivity
T
t
Edge
LED
Output pulse
Direction of movement
= Pulses are suppressed
= Pulse length ist limited
OPSL 775
Laser edge detector
