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Introduction – Rockwell Automation 440L GuardShield PAC Type 4 Safety Light Curtain User Manual

Page 5

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GuardShield™ PAC Safety Light Curtain Installation Instructions

3

Original instructions

GuardShield PAC Safety Light Curtain

Introduction

The GuardShield PAC safety light curtain is a multiple beam,
presence sensing device designed for perimeter or access
detection around hazardous machinery or equipment The
GuardShield PAC is a Type 4 AOPD per IEC 61496. It is a self
contained, optically synchronized, two box (transmitter and
receiver) safety light curtain with dip switch selectable operating
modes.

The GuardShield PAC safety light curtain consists of a non-
matched pair of optic units, i.e., transmitter and receiver. The
transmitter and receiver operate on +24V DC. The maximum
distance between transmitter and receiver is referred to as the
protective field width or range. The protective field height is the
distance between the first and last beam in the device.

The transmitter emits sequential pulses of infrared light which are
received and processed by the GuardShield PAC receiver. The
synchronization of the timing of the emission and reception of
infrared light pulses is accomplished optically by the first beam
adjacent to the GuardShield PAC status LEDs. This beam is
referred to as the synchronization beam. Because the
GuardShield PAC transmitter and receiver are optically
synchronized, no electrical connection is required between the
transmitter and receiver.

The GuardShield PAC receiver has two safety outputs, Output
Signal Switching Devices (OSSDs) and one nonsafety auxiliary
output. When the GuardShield PAC transmitter and receiver are
properly powered and aligned, all OSSDs are current sourcing
+24V DC with a switching capacity of 500 mA. The two safety
OSSDs are cross monitored and short-circuit protected.
Interruption of the sensing field causes the receiver to switch the
sourced current OFF (0V DC).

Restoring the GuardShield PAC sensing field, (in Guard only
configuration) causes all outputs (OSSDs) to switch to the active
high state (resume current sourcing +24V DC with a switching
capacity of 500 mA).

The GuardShield PAC is offered in a number of configurations
based on a standard Type 4 safety light curtain platform.

In addition to the standard GuardShield PAC, the GuardShield PAC
is offered with an integrated laser alignment system or with an
integrated laser alignment system with connectivity to
ArmorBlock Guard I/O. The ArmorBlock Guard I/O optim allows
network connectivity providing OSSDs over a DeviceNet™ or
DeviceNet safety network. The ArmorBlock™ Guard I/O option is
only available in GuardShield PACs with integrated laser
alignment systems.

Selectable functions of the GuardShield PAC and GuardShield PAC
with integrated laser alignment are:

• Beam coding

• EDM (External Device Monitoring)

• Start interlock

• Restart interlock

Selectable functions of GuardShield PAC with ArmorBlock Guard 
I/O connectivity:

• Beam coding

Range of Uses of the Device

The GuardShield PAC safety light curtain is classified as electro-
sensitive protective equipment (ESPE). The maximum protective
field width is 16m (52.5ft) for the GuardShield PAC.

The device is a Type 4 ESPE as defined by IEC 61496-1 and CLC/TS
61496-2 and is therefore allowed for use with controls in safety
category Type 4 in compliance with EN ISO 13849, SIL CL3 in
accordance with EN 62061 or up to PLe in accordance with EN ISO
13849. The device is suitable for:

• Hazardous area protection

• Access protection

Access to the hazardous point must be allowed only through the
protective field. The machine/system is not allowed to start as
long as personnel are within the hazardous area. Refer to the
“Examples of Range of Use” on page 6 for an illustration of the
protection modes.

The GuardShield PAC is intended as a perimeter or access
protection device for a whole body detection and can not be used
in horizontial detection applications as it may be possible for
personnel to step between the beams and access the hazard
without being detected.

Depending on the application, mechanical protection devices
may be required in addition to the safety light curtain.

GuardShield PAC Laser Alignment

The laser light source in the integrated laser alignment system of
the GuardShield PAC light curtains is a Class 1, eye safe laser diode
with a wavelength of 670 nm.

IMPORTANT

These installation instructions are designed
to address the technical personnel of the
machine manufacturer and or the installer of
the safety system regarding the proper
mounting, configuration, electrical
installation, commissioning, operation and
maintenance of the GuardShield safety light
curtain.

These installation instructions do not provide
instruction for the operation of machinery to
which the GuardShield safety light curtain is,
or will be, integrated. Only qualified
personnel should install this equipment.

IMPORTANT

Additional measures may be necessary to
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).