CAUTION: Use of EZ-SCREEN Type 2
EZ-SCREEN Type 2 meets the Type 2 requirements of IEC 61496 and Category 2 PLc requirements of EN ISO
13849-1. DO NOT use EZ-SCREEN Type 2 unless it is installed, tested, and inspected in accordance with this
manual. DO NOT use EZ-SCREEN Type 2 where Control Reliability is required, or where Category 3, Category 4, or
Type 4 AOPD
(active
opto-electronic
protective
device) have been mandated, or where a risk assessment has
determined that frequent access by personnel to the hazard could result in an irreversible or serious injury (for
example, OSHA reportable injury).
Typical use is for safeguarding in
situations
where the consequence of an accident will result in only slight
(normally reversible) injuries that are typically treated by the normal healing processes and minor medical
treatment (that is,
first
aid, as
defined
by OSHA 29CFR1904.7).
Failure to follow these
instructions
could result in serious bodily injury or death.
2.3.1 Examples: Appropriate
Applications
EZ-SCREEN Type 2 are typically used for, but is not limited to, the following
applications
(dependent on machine risk assessment):
• Small assembly equipment
• Automated
production
equipment
• "Table-top"
robotic
work cells
• Component
insertion/"pick-and-place"
machines
• Small packaging machines
• Equipment and process
protection
(non-personnel safety)
•
Applications
that could result in only slight (normally reversible) injuries (such as bump, bruise, knock-down, trapping but not
crushing, minor cuts and abrasions, etc.)
2.3.2 Examples: Inappropriate
Applications
Do not use EZ-SCREEN Type 2 in the following
applications:
• As a primary safeguard in frequently accessed hazardous
situations
that could result in serious injuries (normally irreversible,
including death)
• In any case where Control Reliability, Category 3, Category 4, or Type 4 AOPD
(active
opto-electronic
protective
device) have
been mandated. See EN ISO 13849-1, IEC 61496-1, or other appropriate standard
• With any machine that cannot be stopped immediately
after
a stop signal is issued, such as single-stroke (or
full-revolution)
clutched machinery
• With any machine with inadequate or inconsistent machine response
time
and stopping performance
• With any machine that ejects materials or component parts through the
defined
area
• In any environment that is likely to adversely
affect
photoelectric sensing
efficiency.
For example, corrosive chemicals or
fluids
or unusually severe levels of smoke or dust, if not controlled, may degrade sensing
efficiency
• As a tripping device to
initiate
or
reinitiate
machine
motion
(PSDI
applications),
unless the machine and its control system fully
comply with the relevant standard or
regulation
(see OSHA 29CFR1910.217, ANSI/NFPA 79, ANSI B11.19, ISO 12100, IEC
60204-1, IEC 61496-1, or other appropriate standard)
If an EZ-SCREEN Type 2 is installed for use as a perimeter guard (where a pass-through hazard may exist, see
on page 14), the dangerous machine
motion
can be
initiated
by normal means only
after
the safeguarded area
is clear of individuals and the EZ-SCREEN Type 2 has been manually reset.
2.4 Control Reliability and Safety Categories
To summarize the expected safety circuit performance in high-risk
situations,
requirements of Control Reliability (OSHA 29CFR1910.217
and ANSI B11.19)) and Category 3 and Category 4 (EN ISO 13849-1) demand that a reasonably foreseeable, single failure does not lead
to the loss of the safety
function,
and does not prevent a normal or immediate stop from occurring. The failure or the fault must be
detected at or before the next demand of safety (e.g., at the beginning or end of a cycle, or when a safeguard is actuated). The safety-
related part of the control system then must issue an immediate stop command, or prevent the next machine cycle or hazardous
situation
until
the failure or fault is corrected.
The
effect
of ANSI B11.19, and EN ISO 13849-1 is to set a baseline for
situations
in which a minimum level of performance has been
mandated or in cases where a risk assessment has determined a need for Control Reliability, Category 3 or Category 4 level of
performance.
In lower-risk safety
applications,
safeguards and safety circuits do not require the level of performance and fault tolerance described by
Control Reliability, Category 3 or Category 4.
Applications
involving
situations
that could result in a slight or normally reversible injury
(e.g., only requiring
first
aid, as
defined
by OSHA 29CFR1904) can be solved by EN ISO 13849-1 Category 2.
EN ISO 13849-1 Category 2 does not require the same level of performance and fault tolerance as required by Control Reliability,
Category 3 or Category 4. Safety-related parts of control systems designed to Category 2 “shall be designed so that their
function(s)
are
checked at suitable intervals by the machine control system.” This allows a single fault to lead to the loss of the safety
function
between
EZ-SCREEN
®
Type 2 Light Screen
8
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