IDEC SG4 Type 4 Finger & Hand - Manual (Page 8)

SG4-B Series Instruction Manual
4
1.3. How to choose the device
There are at least three different main characteristics that should be
considered when choosing a safety light curtain, after having
evaluated the risk assessment:
1.3.1. Resolution
The resolution of the device is the minimum dimension that an
opaque object must have in order to obscure at least one of the
beams that constitute the sensitive area.
The resolution strictly depends on the part of the body to be
protected.
R = 14mm Finger protection
Type 4
R = 30 mm Hand protection
Type 4
As shown in Fig.1, the resolution only depends on the geometrical
characteristics of the lenses, diameter and distance between centres,
and is independent of any environmental and operating conditions of
the safety light curtain.
Fig. 1
The resolution value is obtained applying the following formula:
R = I + d
where:
I = Distance between two adjacent optics
d = Lens diameter