Pinnacle Systems SS - Manual (Page 8)

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Introduction
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The Model SS is an Infrared safety light curtain that is
designed to the IEC 61496 standard. When properly
installed, it protects the machine operator by passing
an invisible infrared light beam across an area to be
guarded and examining whether or not the light beam(s)
are blocked. If the light beam(s) are blocked, monitored
solid state outputs will open, issuing a “STOP” command
to the machines normally closed (N.C.) “STOP” circuit.
The System is composed of a transmitting unit (EMIT-
TER), and a receiving unit (RECEIVER). The entire
system is control reliable Category 4 (Must be installed
with a control reliable safety circuit per IEC 61496) in
that a single fault anywhere within the Model SS will
not prevent at least one of the solid state outputs from
opening up (allowing a “STOP” command) when either
a beam is broken or an internal fault occurs.
Theory of operation. The Model SS protects an area
by projecting a curtain of infrared light. The infrared
emitters and receivers face each other across the fi eld
to be protected. Each emitter/receiver pair is spaced
along the length of the pylons at regular intervals from
.5”, up to 8” depending on the application. The smaller
spacing are for fi nger guarding, the larger spacing are
for body guarding.
The emitter/receiver pairs are scanned sequentially (one
at a time) by a very short pulse of infrared light starting
from bottom (cable end), and working up to the top, until
every beam pair has been scanned. Two 16 bit comput-
ers in the emitter pylon and two 16 bit computers in the
receiver pylon control the operation, as well as cross
check each pylon.
The System. The Model SS employs infrared technol-
ogy in a small sealed NEMA 4 aluminum housing with
a infrared passing (daylight fi ltering) acrylic lens. This
system provides harmless invisible protection and an
unobstructed view of the guarded area. There are two
parts to the
Model SS: An Emitter pylon and A Receiver
pylon. The Emitter pylon has no outputs, but does con-
tain a digital CAN data network to allow it to be linked
to the Receiver pylon (although not required for opera-
tion). The Receiver pylon contains the digital CAN data
network and two monitored solid state 24vdc outputs.
Both pylons synchronize to each other either via the
CAN data network or the bottom beam (beam closest
the cable).
System Safety. The Model SS employs redundant,
and diverse technology that provides a backup for every
system that could cause an unsafe condition.
In the Emitter pylon, 1 CPU drives the Infrared LED’s
while the 2
nd CPU monitors to assure proper signals and
timing. Improper operation from either CPU will turn off
the Infrared LED’s.
In the Receiver pylon, 1 CPU drives the Infrared receiv-
ers while the 2
nd CPU monitors to assure proper signals
and timing. Both CPU’s are required to drive the solid
state outputs as well as monitor the condition of the out-
put. Either CPU can shut down both solid state outputs.
Signals shared between CPU’s are isolated from each
other to prevent a failure of 1 microprocessor causing
a failure in the 2
nd . Watchdog circuits on the solid state
outputs automatically shut off the outputs should either
CPU slow down or lock up.
Solid state outputs are turned on separately to be
checked to make sure neither output has been shorted,
before fully turning on.
Safety Features. Designed to meet IEC 61496, UL
1998, UL subject 491, OSHA, ANSI
Microprocessor redundancy for both Emitter and Re-
ceiver pylons
Redundant, monitored, 24vdc solid state outputs
Watchdogs on CPU’s and outputs prevent unintentional
output during lockups.
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Introduction