SICK WEU 26/2, WSU 26/2 Technical Description

TECHNICAL DESCRIPTION

WSU 26/2 – WEU 26/2

Photoelectric Safety Switch

‡ EASY INSTALLATION †

‡ UNIVERSAL USABILITY†

‡ SOLID CONSTRUCTION †

Contents

SICK WSU 26/2 – WEU 26/2

1 General Introduction 3

2 Device/System

Construction 4

3 Description of Function 4

Possible Areas of Application and Application Conditions

4.1 Possible Areas of Application 5

4.2 Application Conditions 5

5 Mechanical Arrangement

and Mounting 6

5.1 Safety Distance 6

5.2 Mechanical Mounting 7

5.3 Multiple Safeguarding 8

5.3.1 Mutual Interference 8

5.4 Corner Mirrors 10

6 Mounting 11

6.1 Mounting Requirements 11

6.2 Detecting Reflections 11

7 Electrical Connection 13

7.1 General 13

7.2 Wiring Diagram 14

12 Technical Data 25

13 Dimensional Drawing 26

At a glance: What is new?

15 Selection Table,

WSU/WEU 32

15.1 Conversion List 33

16 Selection Table,

Accessories 34

Standards and Regulations

To be observed in use and installation

Approvals

EU Europe

EC prototype test conducted by

BG - Berufsgenossenschaft (Trade association) Fachausschuß Eisen und Metall III (Technical committee for iron and metal III) Graf-Recke-Str. 69 D-40239 Düsseldorf

Approval number: 97074

8 Commissioning 22

8.1 Alignment of WSU and WEU 22

8.2 Alignment of WSU and WEU with Alignment Aid AR 60 22

8.3 Checking 22

9 Maintenance 23

10 Commissioning 23

11 Malfunctions 23

11.1 Diagnostic Elements 23

This technical description must be observed when installing and commissioning the WSU 26/2 - WEU 26/2. Inspection and commissioning must be carried out by specialists, if this is specified in the directives or guidelines.

Warning

Failure to observe may result in dangerous operation

Usage

Information regarding how to use the product correctly and efficiently

Generally recognized technical regulations and quality assurance system ISO 9000 are carefully applied during the development and production of SICK products.

SICK WSU 26/2 – WEU 26/2

1 General Introduction

The WSU 26/2 / WEU 26/2 photoelectric safety switch is a single-beam non-contact protective system. It consists of a WSU light sender and a WEU light receiver. The light beam between the emitting and receiving units provides access protection for hazardous areas.

The safety switch is designed for industrial applications. Its features include

‡ universal usability ‡ easy installation ‡ solid construction ‡ heated front screen, i.e. it can be

deployed even in unfavorable ambient conditions.

The WSU/WEU complies with safety requirements according to pr EN 50.100, safety category type 4.

The following key data are applicable in practical use:

Beam diameter

WSU WEU

Fig. 1: System construction of the WSU 26/2 / WEU 26/2 photoelectric safety switch

Scanning range 0.5 ... 18 m

15 ... 70 m

Beam diameter 23 mm

23 mm

Range

3 Description of Function

2 Device/System Construction

SICK WSU 26/2 – WEU 26/2

The WSU/WEU comprises:

‡ WSU 26/2 sender unit and ‡ WEU 26/2 receiver unit

Each complete break in the light beam between the light sender and light receiver triggers a signal which can be used to immediately stop the dangerous movement of the power-driven machinery (abbreviated as ”PDM”).

The WSU/WEU 26/2 must not be used as a hand or finger guard.

3 Description of Function

The WSU and WEU are mounted separately in die-cast housings. Each has its own power supply (Fig. 2). The WSU contains a clock generator and the sender diode. The diode emits infrared pulses at the clock rate set by the generator, which are evaluated by the receiver unit WEU if the light path is uninterrupted. The WEU contains the output relays A and B, which pick up if the light path is uninterrupted. If the light path or the connection between terminals 10 and 11 on the WSU is interrupted (testing), both relays are released.

The WSU 26/2 / WEU 26/2 serves as a protective cut-off device to protect hazardous areas on powerdriven machinery. The machinery may be:

‡ plastics machinery ‡ stackers ‡ settling machinery

in the stoneworking industry

‡ machining centers

1 Connection

for power supply 2 Power supply 3 Clock generator 4 Sender diode 5 LED, WSU 6 LED, WEU 7 Photoelectric converter 8 Amplifier 9 Relay with positively-driven contacts 10 Outputs 11 Test contact

Fig. 2: Principle of function of the WSU/WEU 26/2, AC version

SICK WSU 26/2 – WEU 26/2

4 Possible Areas of Application and Application Conditions

4 Possible Areas of Application

4.1 Possible Areas of Application

The WSU/WEU provides access protection for hazardous areas (Fig. 3).

4.2 Application Conditions

Safe cut-off can only be effected when the light beam diameter of 23 mm is fully covered.

The protective function of the WSU/WEU is ensured when the conditions set out in the adjacent box are met.

The power-driven machinery (”PDM”) must be controllable by electrical means.

The dangerous movement of the machine must be able to be stopped at any time.

The WSU/WEU must be positioned so that entry into the hazardous area is only possible by breaking the light beam.

The command unit must be positioned so that it cannot be activated from the hazardous area.

5 Mechanical Arrangement

5 Mechanical Arrangement and Mounting

SICK WSU 26/2 – WEU 26/2

5.1 Safety distance

The WSU/WEU must be attached such that, if the light beam is broken during hazardous movement of the machinery, the point-of-operation can only be reached when this hazardous movement has ceased. For this purpose, a safety distance S must be maintained between the nearest boundary of the point-of-operation and the light beam (Fig. 4). The safety distance depends on the machine stopping time and on the approach speed of the personnel.

The machine stopping time must be determined by repeating measurements under practical conditions. 1.6 m/s is the recommended approach speed. The safety distance is calculated as follows:

S = v (t

+ t2) + C

Mechanical safeguarding

Entry/exit guarding with WSU/WEU

Fig. 4: Safety distance to light beam

Direction of entry into hazardous area

Table 1 shows which C value must be used for which application.

Point-of-operation

S Safety distance (mm) v Approach speed

1.6 m/s

Machine stopping time (ms)

Response time of WEU (22 ms)

C Dependent on number of beams

(1, 2, or 3), see Table 1

pr EN 999 Safety of machinery Approach speed of body parts for arrangement of protective systems

Number of beams 01 02 03

Height of beam(s) 750 400 0300 above floor (mm) 900 0700

1100

C 1200 850 0850

Table 1: Height of beams above floor

The WSU/WEU must be attached such that, if the light beam is broken during hazardous movement of the machinery, the pointof-operation can only be reached when the power-driven machinery is no longer in a hazardous state.

For this purpose, a safety distance must be maintained between the light beam and the nearest boundary of the point-of-operation. This safety distance is determined according to pr EN 999.

People within the hazardous area but outside the light beam are not detected. It must, however, be ensured that any hazardous state can only be initiated when there is no one in the hazardous area.

Use and mounting of the protective systems is subject to the relevant official rules and regulations. These provisions differ depending on the area of application.

SICK WSU 26/2 – WEU 26/2

5.2 Mechanical Mounting

The WSU and WEU units can be mounted on one of the sides of their housing or using the mounting bracket, depending on site circumstances. The mounting bracket greatly assists alignment. The devices can be mounted in any operating position. However, the WSU and WEU should be mounted such that the axis of the light beam emitted by the WSU always matches the axis of the WEU optic (alignment sight).

The mounting brackets should be affixed so that all fixing screws are easily accessible for alignment purposes. Figure 5 shows examples. The devices should be attached such that the opposing device can be aligned in the alignment sight.

When using the 15 + PE plug, mounting modes a and b are not possible.

Order number Mounting bracket 2 007 900

If, for reasons of space, the devices need to be arranged as shown in Figures 5 a and b, hexagon screws must be used.

Fig. 5: Mounting options using a mounting bracket

5.3 Multiple Safeguarding

When using two WSU/WEU units in a protective system, the possibility of mutual interference must be excluded. Since the light beam of the WSU diverges, the cross-section of the beam increases as the distance between the WSU and WEU grows. The following conditions must therefore be met when arranging the WSU/WEU:

SICK WSU 26/2 – WEU 26/2

approx. 900

approx. 400

5.3.1 Mutual Interference

The light beam of the WSU must only be received by the corresponding WEU. To prevent mutual interference between several WSU/WEU installations arranged adjacent to or above each other, the specified beam diameters must be taken into account when mounting the devices (Fig. 6).

There are two versions of the WSU, for operating ranges

0.5 ... 18 m and 15 ... 70 m. The WSU must not be used for operating ranges below 15 m. The operating range is given on the rating plate.

Mutual interference is possible

Corner mirror

Fig. 6: Safeguarding a hazardous area with WSU/WEU

SICK WSU 26/2 – WEU 26/2

WEU

WSU

WEU

Fig. 7: Mounting of two WSU/WEU units in series

WSU

WEU

5.4 Corner mirrors

SICK WSU 26/2 – WEU 26/2

In conjunction with corner mirrors, the WSU/WEU provides multisided, two-beam access protection (Fig. 8 and 9).

Corner mirror

Hazardous area

Power-driven machinery (PDM)

Corner mirror

Hazardous area

Power-driven machinery (PDM)

Corner mirror

The use of corner mirrors reduces the scanning range of the WSU/WEU system as cited in the table.

Number of mirrors Reduced scanning range Reduced scanning range

0.5 ... 18 m WSU 15 ... 70 m WSU

1 17 m 67 m 2 15.5 m 61 m 3 13 m 51 m 4 11 m 42 m

Tab. 2: Reduction in scanning range when using corner mirrors

Corner mirror

Safety distance Reflection possible

Fig. 8: Multi-sided protection of hazardous areas

too small

Corner mirror

Fig. 9: Two-beam protection with a WSU/WEU 26 system

The use of more than 2 mirrors requires a very accurate alignment.

SICK WSU 26/2 – WEU 26/2

6 Mounting

6.1 Mounting Requirements

The devices should be mounted and connected in accordance with the on-site application conditions and connections, taking account of the following:

The scanning range is based on the width of the area being protected. Bypassing or encircling must be prevented by suitable (mechanical) means. Where one or more WSU/WEU units are used, the height and number of light beams must comply with the applicable regulations. There must be no reflective surfaces in the emitting or receiving beam path. The minimum distance must be maintained.

6 Mounting

6.2 Detecting Reflections

The light beam must not be unintentionally reflected back to the receiver by reflective surfaces. Reflections can be detected as follows:

Entry direction

Central beam

Reflective object (e.g. material container)

Boundary of point-ofoperation

Fig. 10: Incorrect mounting: reflective object in divergent light beam. No detection of the obstacle due to reflection. No protection.

Entry direction

Central beam

Cover the light beam between the sender and receiver fully with an obstacle (100 mm x 100 mm) and slowly move the obstacle from the sender unit to the receiver unit. While this is happening the green LED on the WEU must not light up. If it lights up even just briefly during this check, reflection is occurring. See also 8. Commissioning.

Beam array broken

Reflective object (e.g. material container)

Boundary of point-ofoperation

Fig. 11: Correct mounting, correctly aligned: reflective object outside divergent light beam. No reflection. The obstacle is clearly detected.

+ 24 hidden pages

SICK WEU 26/2, WSU 26/2 Technical Description

Specifications and Main Features

Frequently Asked Questions

User Manual