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GuardShield™ Safe 4 Safety Light Curtain User Manual
Examples of Range of Use
The GuardShield Safe 4 safety light curtain operates as a proper
protective device only if the following conditions are met:
• The control of the machine must be electrical.
• The controlled machine must be able to be stopped any where in
the machines stroke or cycle.
• The transmitter and receiver must be mounted such that access to
the hazard is only through the light curtain's protective field.
• The restart button must be located outside the hazardous area
such that it cannot be operated by a person working inside the
hazardous area.
• The statutory and local rules and regulations must be observed
when installing and using the device.
Additional measures may be necessary to
IMPORTANT
ensure that the ESPE does not fail to danger
when other forms of light radiation are
present in a particular application (i.e., use of
cableless control devices on cranes, radiation
from weld spatter or effects from strobe
lights).
GuardShield Safe 4 Laser Alignment
The laser light source in the Integrated Laser Alignment system of the
GuardShield Safe 4 light curtains is a Class 2, eye safe laser diode with a
wavelength of 630 nm.
This Class 2, eye safe laser is switched from a low output power state to a
high output power state (and back again) by means of control circuitry
which detects reflected laser light from a temporary blockage of the
emitted laser light. This is most commonly accomplished by a person's
finger placed over the laser overlay window. There is also an automatic
shutdown feature that switches the laser diode from the high power state
to the low power state if there is no finger or other interruption detected
for a period of five minutes.
During the high output mode of operation, the laser is pulsed at a rate of
approximately 2 Hz in order to facilitate finger detection in high ambient
light conditions.
To prevent exposure to laser radiation, do
Class 2 Laser
not expose your eyes to the laser. Turn ILAS
off if not in use.
Safety Functions
All GuardShield Safe 4 safety light curtains operated as on/off devices,
meaning the OSSD outputs switch off/on according to an obstruction or
clearing of the detection field.
The protective system must be tested for
IMPORTANT
proper operation after each and every
change to the configuration.
6
System Testing
The GuardShield Safe 4 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.
External Test (Machine Test Signal)
Normally the test input at the transmitter is installed with a short-circuit
jumper to activate the transmitter. A test cycle of the system can be
triggered by an external test signal to the GuardShield Safe 4 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 (see also
page 11).
Response Time
The response time of the GuardShield Safe 4 safety light curtain depends
on the height of the protective field, the resolution, and the number of
light beams (see table on page 20).
IMPORTANT
Determining the Safety Distance
The light curtain must be mounted with proper safety distance
• From the point of danger
• From reflecting surfaces
US Safety Distance Formula
ATTENTION
This distance, referred to as the safety distance, must be properly
calculated prior to determining the safety light curtain protective height
and mounting the light curtains on the machine. Failure to properly
calculate this safety distance may result in operator injury.
IMPORTANT
In the United States there are two formulas that are used to properly
calculate the safety distance. The first, the OSHA formula, is the
minimum requirement for the calculation of the safety distance. The
second formula, the one recommended by Rockwell Automation, is the
ANSI formula, which incorporates additional factors to be considered
when calculating the safety distance.
Original instructions
Determining Stop Time: The measurement of
stopping time (Ts) must include the stopping
times of all devices in the stop circuit. Not
including all device and control system
elements when calculating Ts will result in an
inaccurate safety distance calculation.
The GuardShield Safe 4 safety light curtains
must be mounted at a sufficient distance
from the pinch point or point of operation
hazard to help ensure that the machine stops
before a person's finger, hand, arm(s), or body
reaches the hazard.
Regardless of the calculated safety distance,
GuardShield Safe 4 safety light curtains
should never be mounted closer than six
inches from the point of operation or pinch
point hazard.
R
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