Rockwell Automation 440L GuardShield Type 4 and Remote Teach User Manual - Manual (Page 9)

R
GuardShield™ Safety Light Curtain User Manual
7
Original instructions
EDM is not available in the middle and end segments of a cascading
GuardShield system, however, it is possible to configure this operating
mode in the host segment allowing the whole cascading system to
operate in this mode.
External Device Monitoring (EDM) is not available in GuardShield
light curtains with ArmorBlock Guard I/O connectivity.
System Testing
The GuardShield performs a complete system self-test at power up
and switches to the ON state if the system is properly aligned and the
protective field is unobstructed and the start/restart interlock modes
of operation are deactivated.
External Test (Machine Test Signal)
A test cycle of the system can be triggered by an external test signal to
the GuardShield transmitter. Supplying or removing a signal (+24V
DC) via a N.C. or N.O. switch at the test input deactivates the
transmitter for the duration of the test signal, simulating an
interruption of the protective sensing field. The test input must be
configured via a DIP-switch located in the GuardShield transmitter.
External test signal is not available in the middle and end segments of
a cascading GuardShield system, however, it is possible to configure
this feature in the host segment allowing the whole cascading system
to operate in this mode.
Beam Coding
If several safety light curtains are operating in close proximity to one
another, it is possible that the transmitter’s infrared light from one
GuardShield system is “seen” by another GuardShield system’s
receiver. This would cause a “nuisance” stop. To prevent this optical
interference, the GuardShield has the ability to have the transmitter
generate different beam patterns, which is referred to as “Beam
coding.” Selection and activation of beam coding is accomplished
through DIP-switch settings in both the transmitter and receiver.
The following settings are available in the GuardShield safety light
curtain; noncoded and coded.
Blanking
The GuardShield safety light curtain is capable of fixed blanking of
one or more adjacent beams, exclusive of the synchronization beam.
Floating blanking of one or two beams is also capable of being
configured. It is possible to activate both fixed and floating blanking
simultaneously.
Each cascading GuardShield segment pair functions as a standalone
safety light curtain with its OSSDs connected in series to the host
segment’s OSSDs, therefore, it is necessary to configure fixed and/or
floating blanking in each individual pair segment. This is accomplished
by first aligning all segment pairs and securing the brackets. It is then
possible to open a segment pair’s receiver door using the security tool
provided, set the appropriate DIP switches and perform the teach
function. The successful completion of the teach function changes the
operating mode of that segment pair only.
Fixed Blanking
The fixed blanking mode of operation is activated through DIP-switch
settings located in the GuardShield receiver. The beams to be blanked
are “taught” by depressing the teach button located in the GuardShield
receiver endcap while the object is in the GuardShield sensing field.
The fixed blanking mode of operation is monitored. If any part or all
of the object is removed from the sensing field, the GuardShield
OSSD outputs go to the OFF state.
The GuardShield fixed blanking mode of operation will not be
activated until the teach function is complete and the access door is
closed.
Note: “Hard guards” refer to mechanical barriers.
IMPORTANT
If a test cycle of a cascading system is required, it
is necessary to have all transmitters in a
cascading system configured in the same
condition, i.e. all “active high” or all “active low.”
Beam coding improves resistance to optical
interference.
Beam coding increases the system’s response
time, which may also increase the required
safety distance. Refer to Safety Distance
calculations on page 9 of this manual.
IMPORTANT
IMPORTANT
Balanced areas may require an additional risk
analysis. If no mechanical or other guarding is
used to restrict access to the hazard, the blanked
area must be taken into consideration in the
calculation of the safety distance.
The configuration and activation of fixed
blanking creates a “hole” in the GuardShield
protective field. If the fixed object that is located
in the protective field does not completely fill
the area between the GuardShield transmitter
and receiver it is necessary to obstruct access to
the hazard by additional means. This is usually
accomplished by “hard guarding” the open area.
IMPORTANT