Rockwell Automation 440L User Manual
GuardShield™ PAC Type 4
(Perimeter Access Control)
Safety Light Curtain
User Manual
Important User Information
Because of the variety of uses for the products described in this publication, those responsible for the
application and use of this control equipment must satisfy themselves that all necessary steps have been
taken to assure that each application and use meets all performance and safety requirements, including
any applicable laws, regulations, codes and standards.
Reproduction of the contents of this copyrighted publication, in whole or part, without written permission
of Rockwell Automation, is prohibited.
Throughout this manual we use notes to make you aware of safety considerations:
The illustrations, charts, sample programs and layout examples shown in the guide are intended solely for
purposes of example. Since there are many variables and requirements associated with any particular
installation, Rockwell Automation does not assume responsibility or liability (to include intellectual property
liability) for actual use based upon the examples shown in this publication.
Rockwell Automation publication SGI-1.1, Safety Guidelines for the Application, Installation and
Maintenance of Solid-State Control (available from your local Rockwell Automation sales oce), describes
some important dierences between solid-state equipment and electromechanical devices that should be
taken into consideration when applying products such as those described in this publication.
It is recommended that you save this user manual for future use.
Identifies information about practices or circumstances that can cause an explosion in
a hazardous environment, which may lead to personal injury or death, property
damage, or economic loss.
Identifies information that is critical for successful application and understanding of
the product.
Identifies information about practices or circumstances that can lead to personal
injury or death, property damage, or economic loss. Attentions help you identify a
hazard, avoid a hazard, and recognize the consequences.
SHOCK HAZARD
Labels may be on or inside the equipment (for example, drive or motor) to alert people
that dangerous voltage may be present.
BURN HAZARD
Labels may be on or inside the equipment (for example, drive or motor) to alert people
that surfaces may reach dangerous temperatures.
WARNING
IMPORTANT
ATTENTION
GuardShield™ PAC Safety Light Curtain Installation Instructions
ATTENTION
Failure to read and follow these instructions can lead to misapplication or misuse of the
GuardShield safety light curtains, resulting in injury and damage to equipment.
Conditions required for proper use of the
GuardShield PAC Safety Light Curtain
Please make sure you read and understand these requirements before you select and install the
GuardShield PAC safety light curtain. GuardShield PAC safety light curtains are perimeter access
safeguarding devices. These safety light curtains are intended to be used to provide perimeter access
safeguarding of personnel around a variety of machinery.
The GuardShield PAC family of safety light curtains are general purpose presence sensing devices
which are designed to protect personnel working on or near machinery.
The installation of the GuardShield PAC safety light curtains must comply with all applicable federal,
state, and local rules, regulations, and codes.
It is the responsibility of the employer to properly install, operate and maintain the product as well as
the machinery on which the GuardShield PAC presence sensing device is installed.
GuardShield PAC safety light curtains must be properly installed by qualified personnel.
GuardShield PAC safety light curtains are presence sensing devices and will not protect personnel
from heat, chemicals, or flying parts. They are intended to signal a stop of hazardous machine motion
when the sensing field is broken.
GuardShield PAC safety light curtains can only be used on or around machinery which can be
stopped anywhere in its stroke or cycle.
GuardShield PAC safety light curtains should never be used for guarding full revolution clutched
machinery.
The effectiveness of the GuardShield PAC safety light curtains depend upon the integrity of the
machine control circuit. The machinery that the GuardShield PAC presence sensing device is installed
on should have control circuitry that is fail safe in design.
All stopping mechanisms for the machinery should be inspected regularly to ensure proper
operation. The protected machinery must have a consistent reliable and repeatable stopping time.
Original instructions
1
GuardShield™ PAC Safety Light Curtain Installation Instructions
Generally recognized technical regulations and quality
assurance system ISO 9000 are carefully applied during the
development and production of Allen-Bradley/Guardmaster
products.
This technical description must be followed when installing
and commissioning the GuardShield PAC. Inspection and
commissioning must be carried out by a qualified person.
Table of Contents
GuardShield PAC Safety Light Curtain . . . . . . .3
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Principles of Safe Use and Symbols Used. . . . . . . . . . . . . . . . . . . . 4
Specialist Personnel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Range of Uses of the Device. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Proper Use. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
General Protective Notes and Protective Measures . . . . . . . . . . 4
Product Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Special Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Light Curtain Principle of Operation . . . . . . . . . . . . . . . . . . . . . . . . 5
Examples of Range of Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Safety Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Installation and Mounting. . . . . . . . . . . . . . . . . . . . . . . . . 11
Response Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Determining the Safety Distance. . . . . . . . . . . . . . . . . . . . 9
US Safety Distance Formula . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
OSHA Safety Distance Calculation Formula . . . . . . . . . . . . . . . . . 9
The ANSI Safety Distance Formula . . . . . . . . . . . . . . . . . . . . . . . . . 10
European Safety Distance Formula . . . . . . . . . . . . . . . . . . . . . . . . 10
Multiple GuardShield PACs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Mounting Brackets. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Safety Instructions—Maintenance . . . . . . . . . . . . . . . . . 22
Daily Inspection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Six-month Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Cleaning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Technical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Model Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
IMPORTANT: Save these instructions for
use at a future time.
Rockwell Automation reserves the right to make changes or
revisions to the material contained in this publication and cannot
be held liable for incidental or consequential damages resulting
from the furnishing, performance or use of this material.
Electrical Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Wiring Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Checklist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
System Status Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
System Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Teach Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
Troubleshooting Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
This manual covers the operation and installation of the:
• Standard GuardShield PAC light curtain
• GuardShield PAC with Integrated Laser Alignment system
• GuardShield PAC with Integrated Laser Alignment and
ArmorBlock Guard I/O connectivity
2
Original instructions
GuardShield™ PAC Safety Light Curtain Installation Instructions
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.
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).
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 nonmatched 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 500mA. 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 500mA).
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
Original instructions
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 electrosensitive 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 ENISO
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.
IMPORTANT
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.
3
GuardShield™ PAC Safety Light Curtain Installation Instructions
ATTENTION
Use of controls or adjustments or
performance of procedures other than those
specified herein, may result in hazardous
radiation exposure.
ATTENTION
ATTENTION
Potentially hazardous situation, which, if not
prevented, might lead to serious or deadly
injury.
Failure to observe may result in dangerous
operation.
ATTENTION
be maintained at all times.
Additional mechanical protective devices have to be
installed in a way that hazardous machine elements cannot
be reached without passing through the protective field.
The GuardShield has to be installed in a way that operators
can only operate within the sensing area.
Improper installation can result in serious injury.
Never connect the outputs to +24V DC. If the outputs are
connected to +24V DC, they are in ON-state and cannot stop
hazardous spots at the machine/application.
Never expose the GuardShield to flammable or explosive
gases.
Regular safety inspections are imperative (see maintenance).
Do not repair or modify the GuardShield. The GuardShield
safety light curtain is not field repairable and can only be
repaired at the factory. Removal of either of the GuardShield
endcaps will void the warranty terms of this product.
The GuardShield PAC must not be used with
machines that cannot be stopped electrically
in an emergency.
The safety distance between the GuardShield
and a dangerous machine movement has to
Safety Notes
Please observe the following items in order to
ensure the proper and safe use of the
GuardShield safety light curtain.
This Class 1, eye safe laser is switched from a low output power
state to a high output power state (and back again) by means of
control circuitry which detects reflected laser light from a
temporary blockage of the emitted laser light. This is most
commonly accomplished by a person’s finger placed over the
laser overlay window. There is also an automatic shutdown
feature that switches the laser diode from the high power state to
the low power state, if there is no finger or other interruption
detected for a period of five minutes.
During the high output mode of operation, the laser is pulsed at a
rate of approximately 2 Hz in order to facilitate finger detection in
high ambient light conditions.
Safety Precautions
Principles for Safe Use and Symbols Used
The following instructions are preventive warnings to ensure the
safe and proper operation of the GuardShield PAC. These
instructions are an essential part of the safety precautions and
therefore have to be observed at any time.
Throughout this manual we use the labels AT T E NT I O N and
IMPORTANT to alert you to the following:
Failure to observe may result in dangerous
operation
ATTENTION: Identifies information about practices of
circumstances that can lead to personal injury or death, property
damage, or economic loss.
AT TE N T IO N helps you
• Identify a hazard
•Avoid a hazard
• Recognize the consequences
IMPORTANT: Identifies information that is especially important
for successful application and understanding of the product.
4
Specialist Personnel
The GuardShield PAC safety light curtain must be installed,
commissioned and serviced only by a qualified person. A qualified
person is defined as a person who:
• Has undergone the appropriate technical training
and
• Who has been instructed by the responsible machine
operator in the operation of the machine and the currently
valid safety guidelines
and
• Who has read and has ongoing access to these installation
instructions
Proper Use
The GuardShield PAC safety light curtain must be used only as
defined in the “Range of Uses of the Device.” It must be used only
by qualified personnel and only on the machine where it has been
installed and initialized by qualified personnel.
If the device is used for any other purposes or modified in any
way, warranty claims against Allen-Bradley Guardmaster shall
become null and void.
General Protective Notes and
Protective Measures
IMPORTANT
Original instructions
GuardShield™ PAC Safety Light Curtain Installation Instructions
Transmitter Receiver
• The national/international rules and regulations apply to
the installation, use and periodic technical inspections of
the safety light curtain, in particular:
♦ Machine Directive 98/37/EEC
♦ Equipment Usage Directive 89/655/EEC
♦ The work safety regulations/safety rules
♦ Other relevant health and safety regulations
Manufacturers and users of the machine with which the
safety light curtain is used are responsible for obtaining and
observing all applicable safety regulations and rules.
• The notices, in particular the test regulations of these
installation instructions (e.g. on use, mounting, installation
or integration into the existing machine controller) must be
observed.
• The tests must be carried out by specialist personnel or
specially qualified and authorized personnel and must be
recorded and documented to ensure that the tests can be
reconstructed and retraced at any time.
• The installation instructions must be made available to the
user of the machine where the GuardShield PAC safety light
curtain is installed. The machine operator is to be instructed
in the use of the device by specialist personnel and must be
instructed to read the installation instructions.
Product Description
This section provides information on the special features and
properties of the safety light curtain. It describes the structure
and functions of the unit, in particular the different operating
modes.
® Please read this section before mounting, installing and
commissioning the unit.
Special Features
•Start interlock
•Restart interlock
• External Device Monitoring (EDM)
•Machine test signal
•Beam coding
GuardShield Light Curtain
Principle of Operation
The GuardShield PAC safety light curtain consists of a
nonmatched pair of optic units, i.e. transmitter and receiver with
the same number of beams and spacings. The transmitter and
receiver operate on +24V DC. The maximum distance between
the transmitter and receiver is referred to as the protective field
width or range. The protective field height is the distance
between the first beam and the 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’s status LEDs. This beam is
referred to as the synchronization beam. Because the GuardShield
PAC’s transmitter and receiver are optically synchronized, no
electrical connection is required between the transmitter and
receiver.
The GuardShield PAC’s receiver has two safety outputs, OSSDs
(Output Signal Switching Devices) and one nonsafety auxiliary
output. When the GuardShield PAC’s transmitter and receiver are
properly powered and aligned, all OSSDs are current sourcing
+24V DC with a switching capacity of 500mA. 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’s 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 500mA).
The GuardShield PAC Light Curtain
The GuardShield PAC safety light curtain consists of a transmitter
and a receiver.
Figure 1: Components of the GuardShield PAC
The individual beams of the GuardShield PAC are identified by
markings on the housings.
The width of the protective field is derived from the length of the
light path between sender and receiver and must not exceed the
maximum rated width of the protective field 16m (52.5ft).
The GuardShield PAC is also offered with an integrated laser
alignment system which has a constantly powered Class 1, eye
safe laser located in the top of the GuardShield PAC transmitter
and in the bottom of the GuardShield PAC receiver. Each Class 1,
eye safe laser emits a low level of visible light. Simply blocking this
light below the finger symbol causes the light to be reflected back
to a photo sensor which changes the condition of the laser light. If
this light is at a low level, interrupting it will cause the laser to emit
a highly visible level of light. Interrupting the visible light in the
same location will cause the laser to switch to a low level of
emission. The emission of visible light will also change to a low
level after five minutes of activation.
Across from each laser is a target used to help with the alignment
of the GuardShield PAC pair. Positioning the visible light in the
center of the top and bottom targets will position the
GuardShield PAC pair for optimal alignment.
Original instructions
5
GuardShield™ PAC Safety Light Curtain Installation Instructions
The protective system must be tested for
proper operation after each and every
change to the configuration.
Start interlock is not available in GuardShield
PAC light curtains with ArmorBlock Guard I/O
connectivity.
It is not possible to have both “Start Interlock”
and “Restart Interlock” configured at the
same time in the GuardShield PAC.
Configuring “Restart Interlock” behaves the
same as “Start Interlock” at power up, i.e., a
reset of the system is required at power up.
Restart interlock should always be configured
for the GuardShield PAC light curtains. The
reset switch should be located outside of the
work cell and positioned so that a clear view
of the work cell is possible.
Restart interlock is not available in
GuardShield PAC light curtains with
ArmorBlock Guard I/O connectivity. this
functionality must be configured and
through the safety PLC.
EDM is not available in GuardShield PAC light
curtains with ArmorBlock Guard
I/O connectivity.
Examples of Range of Use
The GuardShield PAC safety light curtain operates as a proper
protective device only if the following conditions are met:
• The control of the machine must be electrical.
• The controlled machine must be able to be stopped any
where in the machines stroke or cycle.
• The transmitter and receiver must be mounted such that
access to the hazard is only through the light curtain’s
protective field.
• The restart button must be located outside the hazardous
area such that it cannot be operated by a person working
inside the hazardous area.
• The statutory and local rules and regulations must be
observed when installing and using the device.
Safety Functions
The GuardShield PAC safety light curtain offers a variety of
functions, which are integral to the system.
Operating modes, functions and features of the GuardShield PAC
system are activated through dip switch settings.
IMPORTANT
Guard Only
When in the guard only mode of operation, the light curtain
operates as an on/off device, meaning the OSSD outputs switch
off/on according to an obstruction or clearing of the detection
field. The GuardShield PAC is shipped from the factory in the
guard only mode.
Start Interlock
The start interlock prevents the OSSD outputs from switching to
ON state after power up of the system with the protective field
unobstructed. A manual reset of the system is required for the
GuardShield PAC to enter the ON state.
This can be accomplished by one of two methods.
• Actuation of a momentary N.O. push button
• Interruption and restoration of the protective field within
one second.
Activation of this mode of operation and selection of the resetting
method is through dip-switch settings. Indication of this mode of
operation is through illumination of a yellow LED on the
GuardShield PAC’s receiver.
IMPORTANT
Restart Interlock
The restart interlock mode of operation prevents the OSSD
outputs from switching to ON after interruption and clearance of
the protective field. A manual reset of the GuardShield PAC
6
Original instructions
system is required. Resetting of the system is accomplished
through a momentary N.O. push button or key switch.
Configuration and activation of this mode of operation is through
dip-switch settings. The Restart Interlock mode is indicated by the
illumination of a yellow LED on the GuardShield PAC’s receiver.
IMPORTANT
External Device Monitoring (EDM) or Machine
Primary Control Element (MPCE) Monitoring
The External Device monitoring function (EDM) is an input signal
to the GuardShield receiver from the Final Switching Device (FSD),
usually relay contactors, which control the hazardous motion of
equipment or machinery. The EDM circuit is required to see a
change of state of the FSD within 300ms of the restoration of the
GuardShield’s sensing field after its interruption. Detection of an
unsafe condition such as a welded contact causes the
GuardShield receiver to go to a lockout condition (OSSDs OFF).
The activation and use of this GuardShield functionality usually
allows the GuardShield’s OSSDs to be connected directly to a
machine’s FSD and attain a Category 4 safety circuit. It is necessary
to have the EDM circuit connected to two separate FSDs which
are wired in series to attain the Category 4 rating. Activation of
this functionality is accomplished by setting the EDM dipswitch
no. three to the OFF position and then performing the “Teach”
function. It is also necessary to connect the GuardShield receiver’s
EDM (yellow) wire to a N.C. output from the FSD.
IMPORTANT
System Testing
The GuardShield PAC performs a complete system self-test at
power up and switches to the ON state if the system is properly
aligned and the protective field is unobstructed and the start/
restart interlock modes of operation are deactivated.
External Test (Machine Test Signal)
A test cycle of the system can be triggered by an external test
signal to the GuardShield PAC’s transmitter. Supplying or
removing a signal (+24V DC) via a N.C. or N.O. switch at the test
input deactivates the transmitter for the duration of the test
signal, simulating an interruption of the protective sensing field.
GuardShield™ PAC Safety Light Curtain Installation Instructions
Beam coding improves resistance to optical
interference.
Beam coding increases the system’s response
time, which may also increase the required
safety distance. Refer to Safety Distance
calculations on page 9 of this manual.
GuardShield GuardShield
PAC
Transmitter
PAC
Receiver
Corner Mirror
Roller Work Path
Power
Supply
Work
Piece
Muting
Module
Work
Piece
The test input must be configured via a dip-switch located in the
GuardShield PAC transmitter.
Beam Coding
If several safety light curtains are operating in close proximity to
one another, it is possible that the transmitter’s infrared light from
one GuardShield PAC system is “seen” by another GuardShield
PAC system’s receiver. This would cause a “nuisance” stop. To
prevent this optical interference, the GuardShield PAC has the
ability to have the transmitter generate different beam patterns,
which is referred to as “Beam coding.” Selection and activation of
beam coding is accomplished through dip-switch settings in both
the transmitter and receiver.
The following settings are available in the GuardShield PAC safety
light curtain; noncoded and coded.
IMPORTANT
Applications and Application Requirements
Figure 2 is an example of a GuardShield PAC three-beam safety
light curtain used as an opto-electronic fence with corner mirror
columns.
Figure 3 is an example of a GuardShield PAC three beam with four
retroreflective sensors and an external muting module.
Figure 2: GuardShield PAC three beam with corner mirror columns
Applications
The GuardShield PAC multi-beam safety light curtain may be used
as an opto-electronic fence; detecting the presence of personnel
as they pass through the sensing field or for safeguarding access
to a hazardous area or machine process. Used in combination
with corner mirrors, the GuardShield PAC multi-beam safety light
curtains provide multiple-side access detection.
When using corner mirrors to protect multiple sides of a machine
or work cell, the GuardShield PAC with integrated laser alignment
is the preferred solution. Activation of visible laser light allows
positioning and adjustment of the transmitter, receiver and
corner mirrors.
A typical system configuration for access detection to a hazardous
area or machine process is to have the GuardShield PAC multibeam safety light curtain connected to an external module along
with two or four sensors. The external module allows material to
pass through the GuardShield PAC multi-beam’s sensing field
without stopping the machine or equipment as long as the
muting conditions are met. As the material is moving through the
process, the GuardShield PAC multi-beam’s sensing field is
interrupted and the outputs switch to the OFF state. However, if
the muting module sensors are interrupted with the proper
timing, the module disregards the GuardShield PAC multi-beam’s
outputs and remains in the ON condition, allowing the machinery
or equipment to continue operation.
If the muting sensors are not interrupted and maintained in the
required timing and or sequence, the muting module will switch
OFF when the GuardShield PAC multi-beam’s sensing field is
interrupted.
Figure 3: GuardShield PAC three beam with muting module
Application Requirements
The protective functions of the PAC can only be used properly
when the following conditions are satisfied:
• The machine or installation must be controlled electrically.
• It must be possible to stop hazardous machine movement.
• The PAC must be installed so that entry into the danger
zone interrupts one or more of the light beams.
The light beam diameter of 23 mm (0.90 in.) must be fully
covered, to assure a change in state of outputs.
Release can only be achieved with the use of a restart switch.
The restart switch must be located such that it cannot be pressed
from inside the danger zone.
The GuardShield PAC should be mounted such that upon
interruption of the light beam, the dangerous location can only
be reached if the dangerous condition of the machine has been
stopped. The requirement for this is that there is a proper safety
Original instructions
7
GuardShield™ PAC Safety Light Curtain Installation Instructions
Tran smit ter
Receiver
Mounting Stand with Corner Mirror
Transmitter
Receiver
Mounting Stand with Corner Mirror
Transmitter Receiver
Mounting Stand with Corner Mirror
Configuration is not allowed.
distance between the light beams and the nearest point of
danger.
Persons situated inside the danger zone, but outside the
protection field are not recognized. It must therefore be ensured
that a dangerous condition is only possible when there is nobody
present in the danger zone.
The relevant legal and government regulations are to be
complied with the implementation of protection installations.
These regulations vary, depending on areas of application.
Corner Mirrors and Mounting Columns
The GuardShield two- and three-beam PACs can be used with one
or two corner mirrors to provide two- or three-sided protection.
The use of each corner mirror reduces the maximum range of the
GuardShield PAC by at least 10% per mirror.
It is possible to use full length corner mirrors (440L-AM075 series,
440L-AM125 series).
Rockwell also offers pedestal floor mounting stands (440LAMSTD) which will accommodate the mounting of the
GuardShield two- or three-beam PAC with the appropriate full
length corner or mirror column mirrors.
Figure 4: Multi-sided access control to danger zones with PAC multibeam safety light barrier
8
Original instructions
Figure 5: GuardShield three-beam PAC and corner mirrors mounted
Determining Stop Time: The measurement of
stopping time (Ts) must include the stopping
times of all devices in the stop circuit. Not
including all device and control system
elements when calculating Ts will result in an
inaccurate safety distance calculation.
ATTENTION
The GuardShield PAC safety light curtains
must be mounted at a sufficient distance
from the hazardous motion to ensure that the
machine stops before a person’s body reaches
the hazard.
to pedestal floor stands
GuardShield™ PAC Safety Light Curtain Installation Instructions
IMPORTANT
Determining the Safety Distance
The light curtain must be mounted with proper safety distance
• From the point of danger
• From reflecting surfaces
US Safety Distance Formula
This distance, referred to as the safety distance, must be properly
calculated prior to mounting the light curtains around the
machinery. Failure to properly calculate this safety distance may
result in operator injury.
Figure 6: GuardShield two-beam PAC and corner mirrors mounted to
pedestal floor stands
Figures 5 and 6 show two- and three-beam GuardShield PACs
with two corner mirrors providing three-sided detection. Mirrors
are offered in either narrow or wide styles in heights to
accommodate two- or three-beam GuardShield PACs.
Response Time
The response time of the two- and three-beam GuardShield PAC
safety light curtain is 20 ms without beam coding or 30ms with
beam coding.
In the United States there are two formulas that are used to
properly calculate the safety distance. The first, the OSHA formula,
is the minimum requirement for the calculation of the safety
distance. The second formula, the one recommended by Rockwell
Automation, is the ANSI formula, which incorporates additional
factors to be considered when calculating the safety distance.
OSHA Safety Distance Calculation Formula
The OSHA safety distance formula as specified in CFR Subpart O
1910.217 is as follows:
Ds = 63 X T
Ds Safety Distance
63 Is the OSHA recommended hand speed constant in
inches per second
Ts Is the total stop time of all devices in the safety circuit,
measured in seconds. This value must include all
components involved in stopping the hazardous
motion of the machinery. For a mechanical power press
it is the stopping time measured at approximately the
90º position of the crankshaft rotation.
S
Original instructions
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