the check [test] of the system, but the loss of safety
function
is detected by the check. By comparison, in a system designed to EN ISO
13849-1 Category 4, a single fault or an
accumulation
of faults will not lead to a loss of the safety
function.
While EN ISO 13849-1 generally applies to the machine level, IEC61496-1/-2
specifies
requirements for the design,
construction
and
testing
for two levels or “types” of
active
opto-electronic
protective
devices (AOPDs) or light curtains (light screens). “Type 2” and “Type
4” describe
differing
requirements to ensure that appropriate safety-related performance is achieved. The appropriate type is
dependent on the overall degree of risk
reduction,
as determined by the machine’s Risk Assessment (see ISO 12100, ANSI B11.19, or
other relevant standard).
A Type 2 AOPD relies on periodic
testing
to detect a failure to danger. Between tests, a single fault can result in the loss of the safety
function.
While this level of performance and fault tolerance is generally not allowed in Category 4
situations,
it is acceptable in the
lower-risk
situations
described by Category 2.
While the EZ-SCREEN Type 2 conducts
continual
internal self-tests and all single faults have been considered, the
installation
should
provide an
additional
periodic test/check of the EZ-SCREEN Type 2 and its interface to ensure the integrity of the safety
function
(see
Manual Reset/Remote Test Input and EDM
on page 31). A component failure detected by periodic test/check must cause a “stop”
signal to be sent to the guarded machine and put the System into a Lockout
condition.
Recovery from this type of Lockout
condition
requires:
• Replacement of the failed component (to restore the safety
function)
• The appropriate reset procedure.
2.5
Operating
Features
The Banner EZ-SCREEN Type 2 Light Screen models described by this manual feature standard
functions:
• Trip or Latch Output (depending on model)
• External Device Monitoring (EDM) via the Test/Retest input
The System Response Time (Tr) can be determined by the model number on the
emitter
and receiver.
2.5.1 Trip/Latch Output
Whether a receiver features Trip or Latch Output determines whether the System will enter RUN mode
automatically
after
power-up, or
if it will require a manual reset
first.
If the System has Trip Output, other measures must be taken to prevent a pass-through hazard.
For Latch Output models, the EZ-SCREEN Type 2 requires a manual reset for the OSSD outputs to turn ON,
after
power is applied and all
beams are clear.
• For Trip Output models, the OSSD outputs will turn ON
after
power is applied and the receiver passes its internal
self-test/
synchronization
and recognizes that all beams are clear. Trip Output models will also turn on
after
all beams are cleared
following a blocked beam.
• For Latch Output models, the EZ-SCREEN Type 2 requires a manual reset for the OSSD outputs to turn ON, whenever power is
applied and all beams are clear.
WARNING: Use of Trip/Latch Output
Application
of power to the Banner device, the clearing of the
defined
area, or the reset of a Latch
condition
MUST
NOT
initiate
dangerous machine
motion.
Machine control circuitry must be designed so that one or more
initiation
devices must be engaged (in a conscious act) to start the machine – in
addition
to the Banner device going into
Run mode. Failure to follow these
instructions
may result in serious bodily injury or death.
2.5.2 Wiring
Options
for
Emitter/Receiver
Swapability
Each EZ-SCREEN Type 2 sensor can be connected to its own power supply or, color-for-color to the other sensor’s cable. The color-for-
color hookup allows the
emitter
and receiver
positions
to be interchanged without rewiring
(functionality
known as sensor "
swapability"). Model CSB..
splitter
cordsets and DEE2R.. double-ended cables facilitate
interconnection
between an EZ-SCREEN Type 2
receiver and
emitter,
providing a single "homerun" cable for
optional
swapable hookup.
EZ-SCREEN
®
Type 2 Light Screen
www.bannerengineering.com - Tel: 763.544.3164
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