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Rockwell Automation Publication 440L-IN012A-EN-P - November 2017
GuardShield Type 4 and GuardShield Remote Teach
When you restore the sensing field in Guard only (automatic reset)
configuration, it causes the OSSD safety outputs to switch from the
OFF to the active high ON state (+24V DC).
Figure 1 - Components of a Standard GuardShield Light Curtain
Safety System
Figure 2 - Components of a Cascaded GuardShield Light Curtain
System
(1)
The black front window indicates the upper and lower limit of the
protective field of the standard GuardShield light curtain system.
The yellow borders on the laser label and target label indicate the limits
of the protective height on the GuardShield light curtain with an
Integrated Laser Alignment system.
The width of the protective field is derived from the length of the light
path between sender and receiver. This width must not exceed the
maximum rated width of the protective field that is provided in the
Technical Specifications on page 22
.
Cascading
The GuardShield light curtain, Type 4 POC is also available in cascade
segments which allow a number of GuardShield light curtain
transmitters and receivers to be interconnected in series (see
).
This product configurability allows the GuardShield light curtain to
protect multiple sides of a machine or simply adds flexibility when
positioning the GuardShield light curtain in various applications.
Standard GuardShield light curtain cascade segments are offered in
protective heights from 320…1760 mm (12.6…69.29 in.) in both 14
mm (0.55 in.) and 30 mm (1.18 in.) resolutions. Cascade segments of
160 mm (6.3 in.) are not offered, however a 160 mm GuardShield light
curtain can be used as the last segment in a cascading system.
Cascading GuardShield light curtains with an integrated laser alignment
system are offered in protective heights from 320…1600 mm (12.6…63
in.). It is possible to mix standard GuardShield light curtains with
integrated laser alignment systems.
A maximum of three GuardShield light curtains can be interconnected
with a common pair of OSSDs. There are no limitations for the total
number of beams in a cascading system. And the maximum number of
beams possible is in three 1760 mm (69.29 in.), 14 mm (0.55 in.)
resolution GuardShield light curtain interconnected segments. The
individual segments can have mixed resolutions, for instance, 14 mm
and 30 mm (1.18 in.) as long as the pairs have the same protective
heights and resolutions.
Cascade segments can be used as standalone light curtain pairs or can
have up to three segments interconnected. These cascading segments all
function as independent light curtains.
When cascade segments are used as standalone pairs or as the last
segment in a cascade system, it is necessary to use a termination plug on
the top connector of the cascade receiver. It is also possible to use a
standard GuardShield light curtain Type 4 POC pair as the last segment
in a cascading system.
Restart interlock is not available in GuardShield light curtains with
ArmorBlock Guard I/O module connectivity.
GuardShield Light Curtain Laser Alignment
The laser light source in the Integrated Laser Alignment system of the
GuardShield light curtains is a Class 1, eye safe laser diode with a
wavelength of 670 nm.
This Class 1, eye safe laser is switched from a low output power state to a
high output power state (and back again) with control circuitry. It
detects reflected laser light from a temporary blockage of the emitted
laser light. This detection is most commonly accomplished by placing a
finger over the laser overlay window. There is also an automatic
shutdown feature. This feature switches the laser diode from the high-
power state to the low-power state if there is no finger or other
interruption that is detected for five minutes.
During the high output mode of operation, the laser is pulsed at a rate of
approximately 2 Hz to facilitate finger detection in high ambient light
conditions.
Safety Functions
The GuardShield safety light curtain offers various functions, which are
integral to the system.
Operating modes, functions, and features of the GuardShield light
curtain system are activated through DIP switch settings.
Guard Only (Automatic Reset)
When in the guard only mode of operation, the light curtain operates as
an on/off device. This operation means that the OSSD outputs switch
off/on automatically according to an obstruction or clear view of the
(1) Figure indicates three cascade segments.
Transmitter
Receiver
Connection to the
Machine Control
Host Segment
ATTENTION:
Use of controls or adjustments or performance of
procedures other than specified, can result in hazardous radiation
exposure.
IMPORTANT
The protective system must be tested for proper operation
after each change to the configuration.
