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Rockwell Automation Publication 450L-UM001F-EN-P - March 2022
Chapter 6 Installation and Wiring
Example for Dpf
The Dpf can be approximated in a perpendicular safety light curtain
application with object sensitivity (effective resolution) less than 63.5 mm
(2.5 in.):
Dpf (inches) = 3.4 × (Object Sensitivity [inch] – 0.276 [inch]), but not
less than 0.
European Safety Distance Formula
A safety distance must be maintained between the light curtain and the point
of danger (
), as described in IEC/TS 62046. This safety
distance helps confirm that the point of danger can only be reached after the
dangerous state of the machine has been removed.
The safety distance as defined in EN ISO 13855 and EN ISO 13857 depends on:
•
Machine stop time
•
Response time of the protective device (safety light c control
circuit)
•
Resolution of the safety light curtain
•
Approach speed to the danger point
•
Position of the AOPD
Figure 35 - Safety Distance from the Point of Danger to the Light Curtain
Tbm
Additional time that is allowed for the brake monitor to
compensate for variations in normal stop time.
Dpf
Depth penetration factor. It is an added distance to allow for how
far into the protective field an object, such as a finger or hand, can
travel before being detected. Dpf is related to the safety light-
curtain object sensitivity. Object sensitivity is the smallest
diameter object that is detected anywhere in the sensing field
(commonly also known as resolution).
Table 30 - Depth of Penetration Factor
Description
Depth Penetration Factor
Finger resolution (14 mm [0.56 in.])
23.7 mm (0.935 in.)
Hand resolution (30 mm [1.19 in.])
78.1 mm (3.077 in.)
Safety
Distance
Protective
Height
Point of
danger
≤75 mm (2.95 in.)
To avoid the possibility of standing between the
protective field and the point of operation, ≤75 mm
(2.95 in.) distance must be maintained.
