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Rockwell Automation Publication 440L-IN012A-EN-P - November 2017
GuardShield Type 4 and GuardShield Remote Teach
Figure 17 - Incorrect Installation
The GuardShield light curtain must be mounted at the proper distance
from the point of operation hazard. This distance is referred to as the
Safety Distance (see
Determine the Safety Distance on page 8
).
Figure 18 - Determine Machine Stopping Time and Safety Distance
Configuration of Operating Modes in Cascading Systems
All operating modes of a standard GuardShield light curtain can be
configured in the host or first segment in a cascading GuardShield light
curtain system. Middle and end segments can only have the following
operating modes/features configured.
• Beam coding
• Floating blanking
• Fixed blanking
All other possible operating modes of a standard GuardShield light
curtain, if configured in a middle or end segment, cause lockout or off
conditions. This condition requires the cycling of power and a
reconfiguration of the segment.
Two Segment Cascading GuardShield Light Curtain Systems
If the GuardShield light curtain pair is vertically mounted so that a
person can stand between the vertical pair and the machine hazard, a
means of detection of that person is required.
There are a few methods of detecting the presence of a person who
could be standing in front of the machine hazard but inside of the light
curtain. Installation of a safety mat or safety laser scanner are possible
solutions. However they are costly solutions as they are separate safety
systems that are integrated into the safety circuit. The most cost-
effective solution is to interconnect an additional light curtain in series
to the vertical pair. Select a Host or cascade pair of GuardShield safety
light curtains with a protective height and resolution that is based on
the results of a risk assessment. Then select the horizontal protective
height of the pair of light curtains. This pair provides detection from the
vertical pair to the front of the machine hazard. Typically, this pair of
light curtains can have a 30 mm (1.18 in.) resolution as their purpose is
to detect the presence of a person and not fingers.
The next step is to select the interconnected patchcords for the
transmitter and receiver. These patchcords are offered in various
lengths. Finally it is necessary to determine if the last segment of the
cascading system is a standard or cascading GuardShield light curtain
pair. Cascade segments that are not connected to another pair of
GuardShield light curtains must have a termination plug that is attached
to the receiver segment.
Figure 19 - Example for a Setup with Two Cascaded Segments
(L-shape Setup)
L-shaped two segment GuardShield light curtain cascade
systems offer protection when it is possible to stand between the
vertical light curtain and the machine hazard
IMPORTANT
You are not able to stand between the protective field and the
point of operation. EN ISO 13855 requires a maximum
distance “X” (see
) of ≤ 70 mm (2.76 in.) at an
installation height of 300 mm (11.9 in.). Check EN ISO 13855
for other installation heights.
Operators can reach hazardous
machine parts without passing through
the protective field.
Operators can step between protective
field and hazardous machine parts.
Middle of Depth of Protective Field
Safety Distance
Point of Operation
Top of tool
Bottom of tool
X
Protective Field Marking
Machine stop time
