GuardShield™ Type 2
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™ Type 2 Safety Light Curtain Installation Instructions
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Conditions required for proper use of the
GuardShield Type 2 Safety Light Curtain
Please make sure you read and understand these requirements before you select and install the
GuardShield Type 2 safety light curtain. GuardShield Type 2 safety light curtains are point of
operation safeguarding devices. These safety light curtains are intended to be used to provide point
of operation safeguarding of personnel on a variety of machinery.
GuardShield Type 2 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.
The GuardShield Type 2 family of safety light curtains are general purpose presence sensing devices
which are designed to protect personnel working on or near machinery.
It is the responsibility of the employer to properly install, operate and maintain the product as well
as the machinery on which the GuardShield Type 2 presence sensing device is installed.
The installation of GuardShield Type 2 safety light curtains must comply with all applicable federal,
state, and local rules, regulations, and codes.
GuardShield Type 2 safety light curtains must be properly installed by qualified personnel.
GuardShield Type 2 safety light curtains can only be used on machinery which can be stopped
anywhere in its stroke or cycle.
GuardShield Type 2 safety light curtains should never be used on full revolution clutched machinery.
The effectiveness of the GuardShield Type 2 safety light curtains depends upon the integrity of the
machine control circuit. The machinery on which the GuardShield Type 2 presence sensing device is
installed 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.
ATTENTION
Failure to read and follow these instructions can lead to misapplication or misuse
of the GuardShield Type 2 safety light curtains, resulting in personal injury and
damage to equipment.
Original instructions
1
GuardShield™ Type 2 Safety Light Curtain Installation Instructions
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Save these instructions for use at a future
time.
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 Type 2.
Inspection and commissioning must be carried out by a
Table of Contents
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Safety Precautions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Principles of Safe Use and Symbols Used . . . . . . . . . . . . . . . . . . 3
Specialist Personnel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Range of Uses of the Device. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Proper Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
General Protective Notes and Protective Measures . . . . . . . . .4
Product Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Light Curtain Principle of Operation. . . . . . . . . . . . . . . . . . . . . 4
Examples of Range of Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Response Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Determining the Safety Distance. . . . . . . . . . . . . . . . . . . . .6
US Safety Distance Formula . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
OSHA Safety Distance Calculation Formula . . . . . . . . . . . . . .6
The ANSI Safety Distance Formula . . . . . . . . . . . . . . . . . . . . . . 6
European Safety Distance Formula . . . . . . . . . . . . . . . . . . . . . . . 6
Installation and Mounting . . . . . . . . . . . . . . . . . . . . . . . . . .8
Correct Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Incorrect Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Multiple GuardShield Type 2s . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Mounting Brackets. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
IMPORTANT
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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Typical Wiring Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Troubleshooting Guide. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Checklist. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Safety Instructions—Maintenance . . . . . . . . . . . . . . . . . 14
Daily Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Six-month Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Date Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Technical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Type 2 Catalog Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
2
Original instructions
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GuardShield™ Type 2 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 Type 2
safety light curtain.
These installation instructions do not provide
instruction for the operation of machinery to
which the GuardShield Type 2 safety light
curtain is, or will be, integrated. Only
qualified personnel should install this
equipment.
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
The GuardShield Type 2 must not be used
with machines that cannot be stopped
electrically in an emergency.
The safety distance between the GuardShield
Type 2 and a dangerous machine movement
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 Type 2 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 Type 2 to flammable or
explosive gases.
Regular safety inspections are imperative (see maintenance).
Do not repair or modify the GuardShield Type 2. The
GuardShield Type 2 safety light curtain is not field repairable
and can only be repaired at the factory. Removal of either of
the GuardShield Type 2 endcaps will void the warranty terms
of this product.
Introduction
The GuardShield Type 2 safety light curtain is a general purpose
presence sensing device, designed for use on hazardous machinery
providing point of operation, as well as, perimeter and access detection.
It is a self-contained, two box, Type 2 ESPE (Electro Sensitive Protective
Equipment).
The GuardShield Type 2 is offered in either guard only mode or with a
restart interlock and EDM.
Safety Precautions
The GuardShield Type 2 may be used in safety applications in which a
risk analysis according to ANSI TR.3, ANSI/RIA 15.06, pr EN 1050 or
EN 959-1 have reached Category 2.
Principles for Safe Use and Symbols Used
The following instructions are preventive warnings for the proper
operation of the GuardShield Type 2. 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 ATTENTION 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 NT IO N h elp s y ou
•Identify a hazard
•Avoid a hazard
• Recognize the consequences
IMPORTANT: Identifies information that is especially important for
successful application and understanding of the product.
Specialist Personnel
The GuardShield Type 2 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
Original instructions
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GuardShield™ Type 2 Safety Light Curtain Installation Instructions
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ATTENTION
Safety Notes
Please observe the following items in order to
ensure compliance of the proper and safe use
of the GuardShield Type 2 safety light curtain.
Range of Uses of the Device
The GuardShield Type 2 safety light curtain is classified as electrosensitive protective equipment (ESPE). The physical resolution is 30 mm
(1.18 in.). The maximum protective field width is 18 m (59 ft) for the 30
mm (1.18 in.) resolution GuardShield Type 2. The protective field
height is between 160 mm (6.3 in.) and 1760 mm (69.2 in.).
The device is a Type 2 ESPE as defined by IEC 61496-1 and CLC/TS
61496-2 and is therefore allowed for use with controls in safety category
Type 2 in compliance with EN ISO 13849, SIL CL2 in accordance with
EN62061 or up to PLd in accordance with EN ISO 13849. The device is
suitable for:
• Point of operation protection (finger and hand protection)
• 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 5 for an illustration of the protection modes.
Depending on the application, mechanical protection devices may be
required in addition to the safety light curtain.
Proper Use
The GuardShield Type 2 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
• The national/international rules and regulations apply to the
installation, use and periodic technical inspections of the safety
light curtain, in particular:
♦ Machine Directive 2006/42/EC
♦ Low Voltage Directive 2006/95/EC
♦ Use of Work Directive 2009/104EC
♦ 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 Type 2 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.
GuardShield Type 2 Light Curtain
Principle of Operation
The GuardShield Type 2 safety light curtain consists of a non-matched
pair of optic units, i.e., transmitter and receiver with the same protected
height and resolution. 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 heig ht 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 Type 2 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 Type 2 status LEDs. This beam is referred to as the
synchronization beam. Because the GuardShield Type 2 transmitter and
receiver are optically synchronized, no electrical connection is required
between the transmitter and receiver.
The GuardShield Type 2 receiver has two safety outputs, Output Signal
Switching Devices (OSSDs) and one nonsafety auxiliary output. When
the GuardShield Type 2 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 Type 2 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 Type 2 Light Curtain
The GuardShield Type 2 safety light curtain consists of a transmitter and
a receiver.
4
Original instructions
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Figure 1: Components of the GuardShield Type 2
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).
The protective system must be tested for
proper operation after each and every
change to the configuration.
The upper and lower limit of the protective field is shown 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 (18 m…30 mm (59.0ft…1.18in.)).
Examples of Range of Use
The GuardShield Type 2 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.
IMPORTANT
GuardShield™ Type 2 Safety Light Curtain Installation Instructions
GuardShield Type 2 is factory ordered with this functionality. Indication
of this mode of operation is through illumination of a yellow LED on the
GuardShield Type 2 receiver.
Restart Interlock
The restart interlock mode of operation is designed to protect against the
OSSD outputs from switching to ON after interruption and clearance of
the protective field. A manual reset of the GuardShield Type 2 system is
required. Resetting of the system is accomplished through a momentary
N.O. push button or key switch. The restart interlock mode is indicated
by the illumination of a yellow LED on the GuardShield Type 2 receiver.
GuardShield Type 2 is factory ordered with this functionality.
Relay Monitoring (MPCE/EDM)
The relay monitoring function is an input signal to the GuardShield
Type 2 receiver and is used to monitor the state of the protected
machinery’s primary control contactors or other final switching device.
Detection of unsafe conditions such as welded contacts, cause the
GuardShield Type 2 to enter a lockout condition (OSSDs OFF).
System Testing
The GuardShield Type 2 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. If the start/restart interlock version is
used, a reset is required to switch to a “green” state.
External Test (Machine Test Signal)
A test cycle of the system can be triggered by an external test signal to the
GuardShield Type 2 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.
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.
Start Interlock
The start interlock is designed to protect against 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 Type 2 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.
Original instructions
Response Time
The response time of the GuardShield Type 2 safety light curtain
depends on the height of the protective field, the resolution and the
number of light beams as well as the coding of the system.
Resolution [mm
(in.)]
30 (1.18) 160 (6.3) 8 20 ms 30 ms
30 (1.18) 320 (12.5) 16 20 ms 30 ms
30 (1.18) 480 (18.8) 24 20 ms 30 ms
30 (1.18) 640 (25.1) 32 20 ms 30 ms
30 (1.18) 800 (31.4) 40 20 ms 30 ms
30 (1.18) 960 (37.7) 48 20 ms 30 ms
30 (1.18) 1120 (44.0) 56 20 ms 30 ms
30 (1.18) 1280 (50.3) 64 20 ms 30 ms
30 (1.18) 1440 (56.6) 72 20 ms 30 ms
30 (1.18) 1600 (62.9) 80 20 ms 30 ms
30 (1.18) 1760 (69.2) 88 20 ms 30 ms
Protective
Height [mm
(in.)]
Number of
Beams
Response Time
w/o Coding
Response Time
5
w/Coding
GuardShield™ Type 2 Safety Light Curtain Installation Instructions
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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.
The GuardShield Type 2 safety light curtains
must be mounted at a sufficient distance
from the pinch point or point of operation
hazard to ensure that the machine stops
before a person’s finger, hand, arm(s), or
Regardless of the calculated safety distance,
GuardShield Type 2 safety light curtains
should never be mounted closer than six
inches from the point of operation or pinch
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
ATTENTION
This distance, referred to as the safety distance, must be properly
calculated prior to determining the safety light curtain protective height
and mounting the light curtains on the machine. Failure to properly
calculate this safety distance may result in operator injury.
machine’s control circuit and any other devices that react to
stop the hazardous motion of the machinery. Not including
the response time of a device or devices in the stop time
calculation will result in insufficient safety distance for the
application. This may result in operator injury.
The ANSI Safety Distance Formula
The ANSI safety distance formula, which is the Rockwell Automation
recommended formula, is as follows:
= K x (TS + TC + Tr + Tbm) + D
D
S
Ds Minimum safety distance between the safe guarding device
and the nearest point of operation hazard, in inches.
K Hand speed constant in inches per second. The ANSI
standard value is 63 inches per second when the operator
begins reaching toward the point of operation hazard from
rest. NOTE: ANSI B11.19 1990 E4.2.3.3.5 states “The
value of the hand speed constant, K, has been determined
by various studies and although these studies indicate speeds
of 63 inches/second to over 100 inches/second, they are
not conclusive determinations. The employer should
consider all factors, including the physical ability of the
operator, when determining the value of K to be used.”
Ts Stop time of the machine tool measured at the final control
element.
Tc Response time of the control system
pf
IMPORTANT
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.
Note: The T
number must include the response times of all
S
devices, including the response time of the safety light
curtain, the safety light curtain controller (if used), the
S
Note: T
Tr Response time of the presence sensing device (safety light
Tbm Additional time allowed for the brake monitor to
Dpf Depth penetration factor. It is an added distance to allow
and Tc are usually measured by a stop time measuring
s
device.
curtain) and its interface, if any. This value is generally stated
by the device manufacturer or it can be measured by the
user.
compensate for variations in normal stopping time.
for how far into the protective field an object, such as a
finger or hand, can travel before being detected. D
related to the safety light curtain’s object sensitivity. Object
sensitivity is the smallest diameter object which will always
be detected anywhere in the sensing field.
is
pf
European Safety Distance Formula
A safety distance must be maintained between the light curtain and the
point of danger. This safety distance helps ensure that the point of danger
can only be reached after the dangerous state of the machine has been
completely removed.
The safety distance as defined in EN ISO 13855 and EN ISO 13857
depends on:
• Stopping/run-down time of the machine or system. (The
stopping/run-down time is shown in the machine documentation
or must be determined by taking a measurement.)
• Response time of the protective device, e.g. GuardShield Type 2
(for “Response Time” see page 5).
• Reach or approach speed.
6
Original instructions
R
GuardShield™ Type 2 Safety Light Curtain Installation Instructions
Safety distance S (Ds)
Protective field height
Point
Distance to avoid standing behind
of
danger
the safety curtain ≤75mm
a
Distance D (meters)
1600
1500
51520310
a (mm)
800
100
900
300
1000
200
1100
400
1200
500
1300
600
1400
700
D (m)
• Resolution of the light curtain and/or beam separation.
Figure 2:
Safety distance from the point of danger
How to Calculate the Safety Distance S
According to EN ISO 13855 and EN ISO 13857:
→ First, calculate S using the following formula:
S = 2000 × T + 8 × (d – 14) [mm]
Where …
T = stopping/run-down time of the machine
+ response time of the protective device [s]
d = resolution of the light curtain [mm]
S = safety distance [mm]
The reach/approach speed is already included in the formula.
→ If the result S is ≤ 500 mm (19.6 in.), then use the
determined value as the safety distance.
→ If the result S is > 500 mm (19.6 in.), then recalculate S as
follows:
S=1600×T+8×(d–14) [mm]
→ If the new value S is > 500 mm (19.6 in.), then use the newly
determined value as the minimum safety distance.
Minimum Distance from Reflecting Surfaces
The infrared light from the sender may be reflected off of shiny surfaces
and be received by the system’s receiver. If this condition occurs, it can
result in an object not being detected when it enters the GuardShield
Typ e 2 s ens in g f ie ld .
All reflecting surfaces and objects (e.g. material bins) must therefore be
located at a minimum distance a from the protective field of the system.
The minimum distance a depends on the distance D between sender and
receiver.
Figure 3:
Minimum distance from reflecting surfaces
How to Determine the Minimum Distance from the
Reflecting Surfaces:
→ Determine the distance D [m] sender-receiver
→ Read the minimum distance a [mm] from the graph:
→ If the new value S is ≤ 500 mm (19.6 in.), then use 500 mm
(19.6in.) as the safety distance.
Example:
Stopping/run-down time of the machine = 290 ms
Response time = 30 ms
Resolution of the light curtain = 30 mm (1.18 in.)
T = 290 ms + 30 ms = 320 ms = 0.32 s
S = 2000 × 0.32 + 8 × (30 – 14) = 768 mm (30.24 in.)
S > 500 mm, therefore:
S = 1600 × 0.32 + 8 × (30 – 14) = 640 mm (25.1 in.)
Example:
In opto-electronic safeguarding, such as with a perpendicular safety light
curtain applications with object sensitivity (effective resolution) less than
2.5 inches, the D
D
(inches) =3.4 × (Object Sensitivity – 0.276),
pf
but not less than 0.
can be approximated based on the following formula:
pf
Original instructions
Figure 4:
Graph, minimum distance from reflecting surfaces
7
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