Rockwell Automation 440L GuardShield Type 4 and Remote Teach User Manual - Manual (Page 15)

R
GuardShield™ Safety Light Curtain User Manual
13
Original instructions
Figure 5: Determining machine stopping time and safety distance
Typical Mounting Configurations of
Cascading GuardShield
Configuration of Operating Modes in Cascading
Systems
All of the operating modes of a standard GuardShield can be
configured in the host or first segment in a cascading GuardShield
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, if
configured in a middle or end segment will cause lock out or off
conditions which require a cycling of power and a reconfiguration of
the segment.
Two Segment Cascading GuardShield Systems;
When the safety distance calculation requires that a GuardShield pair is
vertically mounted at a distance that would allow a person to 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; installing a safety mat or safety laser scanner are possible
solutions, however they are costly solutions as these are separate safety
systems that need to be integrated to the safety circuit. The most cost
effective solution is to interconnect an additional light curtain in series
to the vertical pair. This is accomplished by first selecting a “Host” or
cascading pair of GuardShield safety light curtains with a protective
height and resolution based upon the results of a risk assessment. It is
then necessary to select the horizontal protected height of the pair of
GuardShield light curtains. This pair should provide detection from
the vertical pair to the front of the machine hazard. In most cases this
pair of GuardShields can be 30 mm resolution as their purpose is to
detect the presence of a person, not a person’s fingers or hands.
The next step is to select the interconnect patchcords for the
transmitter and receiver. These patchcords are offered in a variety of
lengths. Finally it is necessary to determine if the last segment of the
cascading system is a standard or cascading GuardShield pair.
Cascading segments that are not connected to another pair of
GuardShield light curtains must have a termination plug attached to
the receiver segment.
Figure 6: “ L-shaped” two segment GuardShield cascading systems offer protection
when it is possible to stand between the vertical light curtain and the machine
hazard
Three Segment GuardShield Cascading Systems
When the use of corner mirrors is not practical or possible, three-sided
guarding of a machine hazard is possible using cascading GuardShield
light curtains.
Middle of Depth of Protective Field
Safety Distance
Point of Operation
Top of tool
Bottom of tool
To avoid the possibility of standing between
the protective field and the point of
operation, the distance must be maintained.
Protective Field Marking
Machine stop time