This document is protected by the law of copyright, whereby all rights established therein remain with the
company SICK AG. Reproduction of this document or parts of this document is only permissible within the limits
of the legal determination of Copyright Law. Alteration or abridgement of the document is not permitted without
the explicit written approval of the company SICK AG.
lease read this chapter carefully before you work with these operating instructions and
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the WSU/WEU26@3 single-beam photoelectric safety switches, referred to in the following
as WSU/WEU26@3 devices.
1.1 Function of this document
These operating instructions are designed to address the technical personnel of the
machine manufacturer or the machine operator in regards to safe mounting, installation,
configuration, electrical installation, commissioning, operation and maintenance of the
WSU/WEU26@3 devices.
These operating instructions do not provide instructions for operating machines on which
the WSU/WEU26@3 devices are, or will be, integrated. Information on this is to be found in
the appropriate operating instructions for the machine.
1.2 Target group
These operating instructions are addressed to planning engineers, machine designers and
operators of plants and systems which are to be protected by the WSU/WEU26@3 devices.
They are also addressed to people who integrate the WSU/WEU26@3 devices into a
machine, initialise its use, or who are in charge of servicing and maintaining the device.
1.3 Scope
These operating instructions are original operating instructions.
These operating instructions are only applicable to the WSU/WEU26@3 single-beam
photoelectric safety switch with one of the following entries on the type label in the field
Operating Instructions:
• 8013336
• 8013336/YTA4
This document is part of SICK part number 8013336 (operating instructions
“WSU/WEU26@3 single-beam photoelectric safety switch” in all available languages).
1.4 Depth of information
These operating instructions contain the following information on the WSU/WEU26@3
devices:
• mounting,
• electrical installation,
• commissioning,
• application,
Planning and using protective devices such as the WSU/WEU26@3 devices also require
specific technical skills which are not detailed in this documentation.
When operating the WSU/WEU26@3 devices, the national, local and statutory rules and
regulations must be observed.
General information on accident prevention using opto-electronic protective devices can
be found in the brochure “Guidelines Safe Machinery – Six steps to the safe machine”.
We also refer you to the SICK homepage on the Internet at www.sick.com.
Here you will find information on:
• sample applications,
• these operating instructions in different languages for viewing and printing,
• EU declaration of conformity and other documents.
1.5 Abbreviations
External device monitoring
Electro-static discharge
Electro-sensitive protective equipment
Light Emitting Diode
Output signal switching device
1.6 Terminology, symbols used
Recommendations are designed to give you some assistance in your decision-making
process with respect to a certain function or a technical measure.
Refer to notes for special features of the device.
LED symbols describe the state of a diagnostics LED. Examples:
RedThe red LED is illuminated constantly.
Yellow The yellow LED is flashing.
Green The green LED is off.
Instructions for taking action are shown by an arrow. Read carefully and follow the
instructions for action.
WARNING
Warning!
A warning notice indicates an actual or potential risk or health hazard. They are designed
to help you to prevent accidents.
Read carefully and follow the warning notices!
Sender and receiver
In drawings and diagrams, the symbol denotes the sender and the symbol denotes
the receiver.
The term “dangerous state”
The dangerous state (standard term) of the machine is always shown in the drawings and
diagrams of this document as a movement of a machine part. In practical operation, there
may be a number of different dangerous states:
his chapter deals with your own safety and the safety of the equipment operators.
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Please read this chapter carefully before working with the WSU/WEU26@3 devices or with
the machine protected by the WSU/WEU26@3 devices.
2.1 Qualified safety personnel
The WSU/WEU26@3 devices must be mounted, commissioned and serviced only by
qualified safety personnel. Qualified safety personnel are defined as persons who
have undergone the appropriate technical training
and
who have been instructed by the responsible machine operator in the operation of the
machine and the current valid safety guidelines
and
who have access to these operating instructions.
WARNING
2.2 Applications of the device
The WSU/WEU26@3 devices are electro-sensitive protective equipment (ESPE), type 4 in
accordance with IEC 61496-1 and IEC 61496-2 and may for this reason be used in
controllers of safety category 4 in accordance with EN ISO 13849, SILCL3 in accordance
with EN 62061 or up to PL e in accordance with EN ISO 13849. The WSU/WEU26@3
devices are used for:
hazardous area protection,
access protection.
The photoelectric switch must be installed such that the hazardous area can only be
reached by interrupting the light path between sender and receiver. It must not be possible
to start the plant/system as long as personnel are within the hazardous area.
The WSU/WEU26-3 devices are intended only for use in industrial environments. When
used in residential areas it can cause radio interferences.
Please refer chapter 3.4 on page 13 for an illustration of the protection mode and an
example application.
Only use the WSU/WEU263 devices as an indirect protective measure!
Opto-electronic protective devices as the WSU/WEU26@ 3 devices cannot provide any
protection against parts thrown out or against radiation. Transparent objects are not
detected.
Depending on the application, mechanical protective devices may be required in addition
to the WSU/WEU26@3 devices.
he WSU/WEU26@3 devices may only be used as specified in chapter 2.2 “Applications of
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the device”. They are only allowed to be used by qualified safety personnel and only on the
machine on which they have been installed and initialised by qualified safety personnel as
per these operating instructions.
All warranty claims against SICK AG are forfeited in the case of any other use, or
alterations being made to the WSU/WEU26@3 devices, even as part of their mounting or
installation.
2.4 General safety notes and protective measures
Safety notes
WARNING
Please observe the following items in order to ensure the correct and safe use of the
WSU/WEU26@3 devices.
• National/international rules and regulations apply to the installation, commissioning,
use and periodic technical inspections of the WSU/WEU26@3 devices, in particular:
– Machinery Directive,
– Work Equipment Directive,
– the work safety regulations/safety rules,
– other relevant safety regulations.
• Manufacturers and operators of the machine on which the WSU/WEU26@3 devices are
used are responsible for obtaining and observing all applicable safety regulations and
rules.
• It is imperative the test notes from page 28 of these operating instructions (“Tests
before the first commissioning”, “Daily functional checks of the protective device”,
“Regular inspection of the protective device by qualified safety personnel”) are followed.
• The tests must be carried out by qualified safety personnel or specially qualified and
authorised personnel and must be recorded and documented to ensure that the tests
can be reconstructed and retraced at any time.
• The operating instructions must be made available to the operator of the machine where
the WSU/WEU26@3 devices are used. The machine operator is to be instructed in the
use of the device by qualified safety personnel and must be instructed to read the
operating instructions.
• The external voltage supply for the devices must be capable of buffering brief mains
voltage failures of 20 ms as specified in EN 60204. Suitable power supplies are
available as accessories from SICK.
• A safety extra-low voltage SELV/PELV must be used to supply power to the
WSU/WEU26@3 devices.
his chapter provides information on the special features, the operating principle, the
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structure and the function of the WSU/WEU26@3 devices.
Please read this chapter before mounting, installing and commissioning the
WSU/WEU26@3 devices.
3.1 Special features
• relay outputs
• rugged type of construction
• high operating range up to 70 m
• front screen heating
3.2 Operating principle of the device
The single-beam photoelectric safety switch consists of a WSU26-3 sender unit and a
WEU26-3 receiver. The sender unit WSU26-3 emits a beam of light that is received by the
receiver unit WEU26-3.
WSU/WEU26&3 devices
WSU26-3WEU26-3
RW
15 ... 70 m
If the light beam is interrupted by an object, a switching command is triggered. The
machine or plant controller that evaluates this message must then bring the dangerous
movement to a halt.
Sender and receiver units are equipped with LEDs for the operational check. Their function
as diagnostic elements is described in chapter 6 “Commissioning”.
The diagnostics LEDs are used for fault diagnosis (see chapter 8 “Fault diagnosis”).
The WSU/WEU26@3 devices are not equipped with an internal restart interlock.
Use the receiver with the permitted operating range to suit the length of the light path
between the sender and receiver!
• If the operating range is too low, the single-beam photoelectric safety switch may not
switch to green.
• If the operating range is too large, the single-beam photoelectric safety switch may
malfunction due to reflections. This would mean that the operator is at risk.
Two receiver with different scanning ranges are available:
Receiver Operating range
WEU26-3-103A00 0.5 ... 20 m
WEU26-3-203A00 15 ... 70 m
3.2.2 Restart interlock
The WSU/WEU26@3 devices do not have an internal restart interlock. It is only possible to
implement a restart interlock for the machine externally. During this process the
WSU/WEU26@3 devices have no control over the restart.
A restart interlock prevents the machine starting again after an error or an interruption of
the light path.
WARNING
Note
WARNING
Always operate the application with restart interlock!
Ensure an external restart interlock is always activated on the machine. The
WSU/WEU26@3 devices are unable to verify if the external restart interlock of the machine
is operable. If you deactivate the external restart interlock, the operator of the machine will
be at acute risk of injury.
3.2.3 External device monitoring (EDM)
The WSU/WEU26@3 devices do not have any feature for monitoring the downstream
contactors. External device monitoring on the downstream contactors is only possible with
an external circuit. You will find additional explanations on the connection of downstream
contactors in chapter 5.2 “System connection”.
An EDM checks if the downstream contactors actually de-energize when the protective
device is tripped.
3.2.4 Front screen heating
Sender and receiver have front screen heating. The front screen heating counteracts the
formation of droplets, mist, frost and ice.
Ensure the optical properties of the front screen are not changed by the formation of
droplets, mist, frost or ice, otherwise there will be a hazard for the operator.
Output signal switching devices off, light path
interrupted or inadequate alignment or device
not yet ready after switch on (see technical
specifications)
Output signal switching devices on, light path
unoccupied, weak signal
Output signal switching devices off, light path
interrupted or inadequate alignment. Prior to the
complete interruption of the light path the signal
was weak.
Subject to change without notice
Operating Instructions Chapter 3
Fig. 4:
Access guarding with
Access guarding with
M
echanical protection
Direction of entry
into the hazardous
WSU/WEU263
Product description
3.4 Application example
he WSU/WEU26@3 devices are used as access protection for hazardous areas on
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machines or systems (Fig. 4). The devices are permanently mounted in the access area
with the necessary safety distance from the nearest hazardous point. If the light beam is
interrupted by an object, a switching command is triggered. The machine or plant
controller that evaluates this message must then bring the dangerous movement to a halt.
his chapter describes the preparation and completion of the installation of the
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WSU/WEU26@3 devices:
• calculating the necessary safety distance,
• calculating the distance from reflective surfaces,
mounting the device.
•
The following steps are necessary after mounting:
• complete the electrical connections (chapter 5),
• alignment of senders and receivers (chapter 6.1),
• testing the installation (chapter 6.2).
No protective function without sufficient safety distance!
WARNING
The reliable protective effect of the single-beam photoelectric safety switches depends on
the WSU/WEU26@3 devices being mounted with the correct safety distance from the
hazardous point.
4.1 Preparation for mounting
4.1.1 Safety distance for access protection
A safety distance must be maintained between the protective field and the hazardous
point. This safety distance ensures that the hazardous point can only be reached after the
dangerous state of the machine has been completely stopped.
The safety distance as per 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 entire protective device,
• reach or approach speed,
• number of beams/beam separation.
Under the authority of OSHA and ANSI the safety distance as specified by
ANSI B11.19 (Annex D) E.4.2.3.3.5 and Code of Federal Regulations, Volume 29,
Part 1910.217 ... (h) (9) (v) 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 entire protective device,
• reach or approach speed,
• other parameters that are stipulated by the standard depending on the application.