Technical data
Leuze electronic
CML 720i Ex
129
Limits for detecting objects
The detection of objects and the evaluation of the data depend on the following factors:
• Beam resolution and cycle time of the light curtain
• Movement speed of the objects
• Transmission rate of the data bytes
• Cycle time of the PLC
Minimum object diameter for detection perpendicular to beam plane
For a moving object, the cycle time of the light curtain must be shorter than the period of time that the object
to be detected is located in the beam plane.
For an object that moves vertically to the beam plane, the following apply:
v
max
[m/s]
= Maximum object speed
L
[m]
= Length of the object in the direction of movement
t
z
[s]
= Cycle time of the light curtain
or
L
min
[m]
= Length of the object in the direction of movement (minimum length)
v
[m/s]
= Object speed
t
z
[s]
= Cycle time of the light curtain
16.3 Minimum object diameter for stationary objects
The minimum object diameter of a stationary object is determined by the beam spacing and optic diameter.
Minimum object diameter for “parallel”-beam mode:
The minimum object diameter depends on the beam spacing because objects also need to be reliably
detected in the transition area between two beams.
NOTICE
Minimum length of the gap between two successive objects!
The gap between two successive objects must be greater than the minimum object diameter.
vmax
L 10mm
–
tz
=
Lmin v tz 10mm
+
=
Beam spacing
Minimum object diameter
5 mm
Beam s 5 mm
= 10 mm
10 mm / 20 mm / 40 mm
Beam s 10 mm
= 20 mm / 30 mm / 50 mm
NOTICE
Minimum object diameter for “crossed beam” mode!
In “crossed beam” mode, the object diameter in the center area is reduced to 1/2 x beam spacing.
