Banner EZ-SCREEN­ Safety Light Curtain Systems - Manual (Page 25)

P/N 133487
23
Banner Engineering Corp. • Minneapolis, U.S.A.
www.bannerengineering.com • Tel: 763.544.3164
Overview
23
Banner Engineering Corp. • Minneapolis, U.S.A.
www.bannerengineering.com • Tel: 763.544.3164
EZ-SCREEN
Instruction Manual
Installation and Alignment
3.1.3 Reset Switch Location
The reset switch must be mounted at a location that
complies with the warning below.
A key-actuated reset switch provides some operator or
supervisory control, as the key can be removed from the
switch and taken into the guarded area. However, this does not
prevent unauthorized or inadvertent resets due to spare keys in
the possession of others, or additional personnel entering the
guarded area unnoticed.
Resetting a safeguard must not initiate hazardous motion.
Safe work procedures require a start-up procedure to be
followed and the individual performing the reset to verify that
the entire hazardous area is clear of all personnel, before each
reset of the safeguard is performed. If any area can not be
observed from the reset switch location, additional supplemental
safeguarding must be used: at a minimum, visual and audible
warnings of machine start-up.
3.1.2 Pass-Through Hazards
A “pass-through hazard” is associated with applications where
personnel may pass through a safeguard (which issues a stop
command to remove the hazard), and then continues into the
guarded area, such as in perimeter guarding. Subsequently, their
presence is no longer detected, and the related danger becomes
the unexpected start or restart of the machine while personnel
are within the guarded area.
In the use of safety light screens, a pass-through hazard
typically results from large separation distances calculated
from long stopping times, large minimum object sensitivities,
reach-over, reach-through, or other installation considerations.
A pass-through hazard can be generated with as little as 75 mm
(3") between the defined area and the machine frame or hard
guarding.
Reducing or Eliminating Pass-Through Hazards
Eliminate or reduce pass-through hazards whenever possible.
While it is recommended to eliminate the pass-through hazard
altogether, this may not be possible due to machine layout,
machine capabilities, or other application considerations.
One solution is to ensure that personnel are continually sensed
while within the hazardous area. This can be accomplished by
using supplemental safeguarding, such as described by the
ANSI B11 series of safety requirements or other appropriate
standards (see Section 3.1.4).
An alternate method is to ensure that once the safeguarding
device is tripped it will latch, and will require a deliberate manual
action to reset. This method of safeguarding relies upon the
location of the reset switch as well as safe work practices and
procedures to prevent an unexpected start or restart of the
guarded machine (see Section 3.1.3).
3.1.4 Supplemental Safeguarding
As described in Section 3.1.1, the EZ-SCREEN components
must be properly positioned such that an individual can not
reach through the defined area and access the hazard point
before the machine has stopped.
Additionally, the hazard can not be accessible by reaching
around, under, or over the defined area. To accomplish this,
supplemental guarding (mechanical barriers, such as screens or
bars), as described by ANSI B11 safety requirements or other
appropriate standards, must be installed. Access will then be
possible only through the defined area of the EZ-SCREEN or
through other safeguarding that prevents access to the hazard
(see Figure 3-3).
The mechanical barriers used for this purpose are typically
called “hard guarding”; there must be no gaps between the
hard guarding and the defined area. Any openings in the hard
guarding must comply with the safe opening requirements of
ANSI B11 or other appropriate standard.
WARNING . . .
Reset Switch Location
All reset switches must be:
• Outside the guarded area,
•
Located to allow the switch operator full, unobstructed view of the
entire guarded area while the reset is performed,
• Out of reach from within the guarded area, and
•
Protected against unauthorized or inadvertent operation (such as
through the use of rings or guards).
If any areas within the guarded area are not visible from the reset
switch, additional safeguarding must be provided, as described
by the ANSI B11 series or other appropriate standards. Failure to
do so could result in serious injury or death.
WARNING . . .
Use of EZ-SCREEN for
Perimeter Guarding
If an EZ-SCREEN System is installed in an application that results
in a pass-through hazard (e.g., perimeter guarding), either the
EZ-SCREEN System or the Machine Primary Control Elements
(MPCEs) of the guarded machine must cause a Latched response
following an interruption of the defined area.
The reset of this Latched condition may only be achieved by
actuating a reset switch that is separate from the normal means of
machine cycle initiation. The switch must be positioned as described
in Section 3.1.3.
Lockout/Tagout procedures per ANSI Z244.1 may be required,
or additional safeguarding, as described by ANSI B11 safety
requirements or other appropriate standards, must be used if a pass-
through hazard can not be eliminated or reduced to an acceptable
level of risk. Failure to observe this warning could result in
serious bodily injury or death.