INTEGRATED

SIGUARD Laser Scanner LS4 

Panoramic Security 

safety 

INTEGRATED

SIGUARD laser scanner LS4 

Panoramic and flexible security 

The maximum degree of protection for man 

and machine is of prime importance – in 

every sector of automated industry. Here, 

the main priority is to provide the highest 

degree of safety for all of those involved in 

the production or the process environment; 

however, it is also important to sustainably 

guarantee the highest possible availability 

of the plants and systems. In order to be 

able to fulfill 100% of these requirements, 

as part of our Safety Integrated safety portfolio, 

we are offering you the reliable 

SIGUARD laser scanner LS4. 

2

Whether mounted on stationary 

machines or on mobile systems such as 

driverless transport vehicles – using 

SIGUARD laser scanners, you can 

perfectly secure your hazardous areas in 

almost every working environment up 

to Category 3 according to EN 954-1. 

Up to four protective and warning field 

pairs for persons and objects can be 

freely set in operation. They can be 

simply programmed using either a PC or 

a laptop which means that they can be 

quickly and flexibly adapted to new 

requirements. 

SIGUARD laser scanners are optical 

distance sensors which detect any 

motion in a 190° working zone. By 

transmitting safe laser pulses and then 

evaluating every reflected pulse, they 

have everything safely in view. And 

when potentially hazardous situations 

do arise, they respond quickly and 

reliably. 

In addition to a conventional 

connection, the new communicationcapable 

versions of our SIGUARD laser 

scanners can be connected reliably and 

in a user-friendly fashion to AS-Interface 

Safety at Work and PROFIBUS with the 

PROFIsafe profile through integrated 

interfaces. Unified, integrated 

communications via standard fieldbuses 

can be implemented in a fail-safe 

fashion by transmitting safety-related 

and standard data together. This means 

that also with our SIGUARD laser 

scanners, you can enjoy the benefits of 

having just one bus coupling. 

SIGUARD laser scanners LS4 – the 

advantages at a glance: 

• Hazardous areas can be contactlessly 

and reliably secured with devices 

which can be universally used: on 

machines, production robots, conveyor 

systems, vehicles etc. 

• Standard versions with fail-safe semiconductor 

outputs 

• Safe direct connection to 

AS-Interface Safety at Work 

• User-friendly version with PROFIBUS 

PROFIsafe connection 

• When scanners are replaced, parameters 

are automatically transferred via 

PROFIBUS 

• Category 3 according to EN 954-1 

• Up to 4 personnel protective and 

warning field pairs which can be 

freely set 

• Protective field with max. 4 m radius 

for personnel safety 

• Extremely compact design 

• Low current drain (approx. 300 mA) 

LS4 laser scanner “Standard“ 

3

Applications 

All hazardous areas under control 

Securing horizontal hazardous areas 

• Personnel and objects are safely and reliably 

detected in the hazardous areas of machines and 

plants 

• Almost any protective and warning fields can be 

flexibly programmed 

Securing horizontal hazardous areas with 

several protective fields 

• Personnel in various hazardous areas can be 

reliably detected by changing-over the protective 

fields 

• Availability is increased by only securing those 

areas which are presently active 

WF 2 

SF 2 

SF 2 

(active) 

WF 1 

(active) 

4

SF 4 

SF 1 

Monitoring the routes of driverless transport 

systems 

• Persons and objects which approach the vehicle 

are reliably detected 

• Laser scanners provide a larger safety area when 

compared to bumpers or protective bars, therefore 

permitting a higher velocity 

SF 2 SF 3 

c 

c 

Collision protection for trolleys 

• Personnel on the route are reliably protected 

• Objects on the route are detected early on and 

damage to the vehicle and load is avoided 

SF1 

SF2 

b 

a 

Additional applications 

• Many ways of securing hazardous areas 

• Securing rooms and providing access control 

• Checking the protrusion length for machine and 

personnel protection 

• Non-safety-related measuring or detection tasks 

(e. g. determining distances, positions or contours) 

5

Function description 

Flexibly master every requirement 

Mode of operation 

The SIGUARD laser scanner LS4 is a scanner which optical- 

E 

Sc 

Reflection 

ly and contactlessly scans areas – and which is predominantly 

used for personnel protection. 

The laser scanner generates a continuous train of bundled 

light pulses using a laser diode and an optical system. An 

integrated rotating mirror distributes these light pulses 

over the complete working area. If objects or persons enter 

this field, then the scanner evaluates the reflected light 

pulses and, using the light propagation time, continually 

calculates the precise position coordinates. If the defined 

personnel protective field is violated, then it brings the 

machine to an immediate stop. 

The operating range of SIGUARD laser scanners LS4 ex- 

0.36° 

tends over 190° and is subdivided into angular segments 

of 0.36°. The scanning rate is 25 scans per second which 

means that a light pulse is transmitted every 40 ms into 

every segment. A special algorithm ensures that objects 

larger than 70 mm – this corresponds to the scanner resolution 

– are reliably detected. However, it also ensures that 

dust and other disturbing effects do not have a negative 

impact on the availability of the system. 

– 5° 

185° 

SIGUARD laser scanners LS4 detect persons – even when 

they are wearing dark clothing – in a safety-related fashion 

up to 4 meters away. Persons and objects can be detected 

at a range of 15 m, for example, to output a warning 

message (however, this is not safety-related). 

Personnel protective field 4 m 

Warning field 

Working area 

15 m 

50 m 

6

Flexibility already on board 

SIGUARD laser scanners can be flexibly adapted to every requirement 

using four variable protective field pairs for personnel 

protective and warning fields. These protective field 

pairs can be simply set at the PC. The SIGUARD laser scanner 

can be used on stationary machines and systems, but it can 

also be used for mobile applications mounted on vehicles, 

driverless transport systems or trolleys. This means, for example, 

that various operating areas of a robot can be secured 

where the laser scanner consecutively scans the different 

areas. Using four programmable protective fields, driverless 

transport systems can be secured e. g. for fast travel, slow 

travel, lefthand and righthand curves. 

SF 3 SF 1 SF 4 

SF 2 

Only personnel protective fields are shown 

Software for every application 

It is extremely easy to precisely set the laser scanner thanks to 

the LS4soft PC operator software. 

The following functions are integrated: 

• Protective fields can be easily configured using either a PC 

or laptop 

• Additional functions such as protective field changeover, 

restart inhibit etc. can be configured using a software 

assistant 

• Extensive range of displays – e. g. defined protective fields, 

actual scan contour, system settings etc. 

• Safe access protection using passwords with various 

authorization stages 

• LS4soft can run under Microsoft Windows 95/98/2000/NT/XP 

7

Standard, PROFIBUS or 

AS-Interface 

The optimum connection 

always available 

SIGUARD laser scanners are available in three connection versions. 

In addition to the standard device with semiconductor 

outputs, communication-capable versions are also available 

which allow the SIGUARD laser scanner LS4 to be directly connected 

to AS-Interface and PROFIBUS. This guarantees seamless 

safety concepts where hazards are essentially neutralized. 

The optimum scanner for your automation environment 

The conventional version of the SIGUARD laser scanner LS4 has 

two fail-safe, self-monitoring, wear-free semiconductor outputs 

which are safely shut down as soon as an object penetrates the 

programmed protective field of the scanner. The two redundant 

outputs can be used to directly switch actuators such as contactors 

or valves. Or, if supplementary functions such as contactor 

feedback or muting are required, these output signals can be fed 

to a separate safety evaluation unit. 

The communication-capable version for AS-Interface 

With Safety at Work, you have the unique opportunity of also 

connecting safety-related devices – such as the LS4 laser scanner 

– directly to the AS-Interface. In this case, the safety-related shutdown 

is realized via the safety monitor. If it has been appropriately 

parameterized, the safety monitor can also simultaneously respond 

to other control devices such as Emergency Stop pushbuttons 

or similar devices. 

As for the standard laser scanner, an optional start button can be 

connected to the unit and the protective fields can be changedover 

directly at the scanner. 

Laser scanner LS4 – AS-Interface Safety at Work 

8

The communication-capable version for PROFIBUS 

Laser scanners which can be directly connected to 

PROFIBUS allow the scanner to be completely operated via 

the bus in a user-friendly fashion. In this case, the safetyrelated 

shutdown as well as the currently active protective 

field are controlled via the bus. The safety-related data 

transfer via the bus uses the PROFIsafe profile. The safetyrelated 

shutdown as well as the selection of the protective 

field is carried out in the safety-related section of a control, 

for instance, in a safe software block of a SIMATIC S7-300F. 

There is a special integrated feature where parameter data 

can be automatically transferred to a new scanner if the 

device has to be replaced. 

Laser scanner LS4 – PROFIBUS 

Parameterization 

The communication-capable scanners are parameterized 

using a PC or laptop which is connected at the serial 

port using a special connecting cable. On the scanner 

side, the magnetically coded key of the connecting 

cable is inserted at the bus interface of the scanner. Instead 

of using an electrical connection as for standard 

scanners, in this case, the data is serially transferred 

through an infrared port. It goes without saying that 

also here the user-friendly LS4soft parameterizing program 

can be used as operator software. The LS4soft is 

provided with every scanner. 

Parameterizing the scanner using the 

optical interface cable 

Safety Integrated 

PROCESS FIELD BUS 

PROFIBUS 

AS-Interface 

9


Technical data 

Protective field data 

Personnel protective field 

Detection range 

0–4 m (no dead zones when correctly mounted) 

Reflection capacity 

Min. 1.8 % (matt black) 

Measuring error Max. 83 mm (for a protective field radius < 3.5 m) 

Max. 100 mm (for a protective field radius > 3.5 m) 

Object size 

70 mm (cylindrical test body) 

Response time 

Min. 80 ms (by version with semi-conductor output) 

Number of protective fields 4 (can be changed-over using switching inputs) 

Output 

Two fail-safe PNP transistor outputs 24 V/250 mA or a safety-related bus coupling 

Category Category 3 acc. to EN 954-1, type 3 acc. to DIN EN IEC 61496-1, IEC 61496-3 

Requirement Class 4 acc. to DIN V 19250, single-fault proof 

Starting 

The start test routine and the start inhibit can be separately parameterized 

Warning field 


0–15 m 

Reflection capacity Min. 20 % 

Object size 

150 x 150 mm 

Response time 

Min. 80 ms (by version with semi-conductor output) 

Number of protective fields 4 (can be changed-over using switching inputs) 

Output 

PNP transistor output, max. 100 mA or bus coupling 

Contour measurement 


0–50 m 

Reflection level Min. 20 % 

Object size - - - 

Output 

Serial RS 232, RS 422 interface 

Resolution, radial 

5 mm 

Resolution, lateral 0.36° 

Optical properties 

Angular range 190° 

Angular resolution 0.36° 

Scan rate 

25 scans/s or 40 ms/scan 

Laser protection class 

Class 1 (safe for the eyes), DIN EN 60825-1, wavelength = 905 nm, 

beam divergence = 2 mrad, timebase = 100 s 

General data 

Electrical supply 

Standard AS-Interface PROFIBUS 

10 

Power supply 

+24 V DC +20 %/–30 %, power supply according to IEC 742 using a safety transformer or 

comparable for DC/DC converters 

Overcurrent protection 

Using a 1.25 A medium-slow-acting fuse in the electrical cabinet 

Current drain Approx. 300 mA Approx. 350 mA Approx. 350 mA 

(use a 2.5 A power supply) 

Power drain Approx. 8 W at 24 V Approx. 9 W at 24 V Approx. 9 W at 24 V 

plus the output load 

Overvoltage protection Overvoltage protection with safe end cut-off according to DIN EN 61496-1 

Voltage dips In compliance with DIN EN 61496-1 

Protective conductor A protective conductor may not be connected up The PROFIBUS cable 

shield must be 

connected to the 

protective conductor

General data 

Inputs 

Restart/reset 

Standard AS-Interface PROFIBUS 

A control device is connected for the “restart inhibit” mode 

and/or device reset, dynamically monitored 

Field pair changeover 4 field pairs are selected using 4 field pairs are selected using Field pair changeover 

4 control lines with internal 4 control lines with internal via PROFIBUS 

monitoring (field pair = 1 protective monitoring (field pair = 1 protective (PROFIsafe profile) 

field and 1 warning field), 24 V DC field and 1 warning field), 24 V DC 

decoupled through an optical coupler) decoupled through an optical coupler) 

Outputs 

Protective field 2x fail-safe semiconductor outputs, AS-Interface, PROFIBUS, fail-safe slave 

PNP max. 250 mA fail-safe slave (Safety at Work) (PROFIsafe profile) 

short-circuit-monitored, 

overcurrent-protected 

Warning field/ PNP transistor output, AS-Interface PROFIBUS 

pollution/fault 

max. 100 mA 

Software 

Operator software 

LS4soft communication and parameterizing software running under Windows 95/98/2000/NT/XP 

with safe protocol for programming 

Interfaces 

RS 232, RS 422 

To parameterize the device and define the fields using LS4soft 

(RS 422 only for standard version) 

Environment and materials 

Degree of protection IP 65 according to IEC 60529 

Shock protection Protective Class 2 

Operating temperature 0 ... +50 °C 

Storage temperature –20 °C ... + 60 °C 

Humidity 

DIN 40040 Table 10, Code letter E (essentially dry) 

Dimensions 140 x 155 x 135 140 x 168 x 165 140 x 168 x 165 

(W x H x D) in mm 

Connection 2 connectors 2 M12 connectors 1 M12 connector, 

(inserted from the top, (AS-Interface and 1 M12 socket 

solder connection) auxiliary voltage) (PROFIBUS input 

1 M12 socket and output), 

(protective field changeover) 1 M12 socket 

(supply voltage), 

1 connector (local restart) 

Control cable length 

Max. 50 m for 0.5 mm 2 cable cross-section, shielded 

Data cable length RS 232 Max. 10 m 

Data cable length RS 422 Max. 50 m (Twisted Pair) 

Transmitter 

Infrared laser diode (905 nm wavelength) 

Housing 

Die-cast aluminum, plastic 

Weight 

Approx. 2 kg 

Vibration stressing 

According to IEC 60068 Part 2–6, 10 - 150 Hz max. 5 G 

over 3 axes 

Continuous shock 

According to IEC 60068 Part 2–29, 10 G, 16 ms 

over 3 axes 

Noise immunity According to DIN EN 61496-1 (corresponding to the requirements for Type 4), 

additionally in accordance with DIN 40839-1/3 

Test pulses 1, 2, 3 a, 3 b and 5 (cannot be used on vehicles with internal-combustion engines) 

Rotating mirror drive Brushless DC motor 

Rotating mirror bearings Maintenance-free ball bearings 

11

Product overview 

SIGUARD laser scanner LS4-4, standard version 

Fail-safe semiconductor outputs 

including the LS4soft software 

3RG7834-6DD00 

SIGUARD laser scanner LS4-4 Safety at Work 

Fail-safe direct connection to AS-Interface 


3SF7834-6DD00 

SIGUARD laser scanner LS4-4 PROFIsafe 

Fail-safe direct connection to PROFIBUS 


3SF7834-6PB00 

Mounting accessories 

Mounting system 

Can be swiveled for simple adjustment 

3RG7838-1AA 

Adapter plate for PLS-mounting 

3RG7838-1AB 

12

Connecting cable 

Connecting cable incl. connector, 15-core, 5 m 





Connector, complete, 15-pin 

Cable lead-away sideways 

3RG7838-1BD 

3RG7838-1BE 

3RG7838-1BF 

3RG7838-1BG 

3RG7838-1BH 

3RG7838-1BB 

PC connecting cable for laser scanner “Standard” 

PC connecting cable incl. connector, 9-core, 3 m 



Connector, complete, 9-pin 

Cable lead-away sideways 

3RG7838-1CC 

3RG7838-1CD 

3RG7838-1CE 

3RG7838-1CB 

PC connecting cable for AS-Interface and PROFIBUS versions 

PC connecting cable, optical magnetic connector, 9-core, 3 m 

3RG7838-1DC 

Maintenance and test accessories 

Cleaning set for the scanner window 

Test object, cylindrical, 500 mm long, 70 mm diameter, 

reflection capacity approx. 1.8 % 

Test object, cylindrical, 1000 mm long, 200 mm diameter, 

reflection capacity approx. 1.8 % 

3RG7838-7RS 

3RG7838-7GB 

3RG7838-7GD 

13

Connection examples 

SIGUARD laser scanner “Standard” with protective field changeover and start button 

+ 24V 

0V 

PE 

• Start button for manual restart directly at the 

scanner (connection 2) 

1,25 

A mT 

Evaluation unit or 

fault-tolerant PLC 

• Alarm output at connection 5 

(e. g. warning lamp) 

• Protective field changeover at 

connections 4, 6, 7 and 8 

1 2 3 4 5 6 7 8 9 101112131415 

X1 

• Safety-related processing of the safe outputs 

(connections 11 and 12) through an evaluation 

unit or fault-tolerant PLC 


SIGUARD laser scanner “Standard” with 3RG7847-4BB evaluation unit 

• Start button for manual restart directly at the 

+ 24V 

0V 

PE 

1,25 

AmT 

Safety output 

+24V 

1 AT 

Contactor 

monitoring 

k4 

k5 

6,3 AF 

6,3 AF 

scanner (connection 2) 

• Permanently set protective field pair 1 

(24 V permanently connected to connection 4) 

A1(L+) 

S1 

S33 S34 S35 S31 S22 

1 2 3 

1 2 3 4 5 6 7 8 9 101112131415 

CH1 

K1 

SIGUARD 3RG7847-4BB 

CH2 

K2 

N.O. 

N.O. 

A2(L- 

S21 S12 

1 2 3 


0V 

K4* 

K5* 

*provide suitable 

spark quenching 

14

SIGUARD laser scanner AS-Interface 

• Directly connected to AS-Interface Safety at Work 

• Safety-related shutdown using the safety monitor 

• Protective field changeover as for the standard 

scanner 

• A local button can be optionally connected for 

manual restart 

• All of the connections are established through 

M12 connectors 

AS-Interface Safety at Work 

AS-Interface 

auxiliary voltage 

or 24 V DC 

Optional: Local 

button for restart 

24 V 

Protective field 1–4 

Addressing socket 


SIGUARD laser scanner PROFIBUS 

• Directly connected to PROFIBUS 

• The shutdown signal is safely transferred via the 

PROFIBUS PROFIsafe profile 

• Safe protective field changeover also via 

PROFIBUS 

• Laser scanners can be quickly replaced thanks to 

the automatic parameter transfer 

• A local button can be optionally connected for 

manual restart 

• All of the connections are established through 

M12 connectors 

PROFIBUS 

24 V DC 

PROFIBUS 

or terminating resistor at the end node 

Optional: Local 

button for restart 

SIGUARD Laserscanner LS4 

15

Fax Order +49/911/9 78-33 21 

SENSORIK 

Sensors in production 

engineering 

Order No. 

6ZB5330-0AC02-0BA0 


Safety Integrated: 

Just how seamless is 

your safety concept? 

Order No. 

E20001-A150-M103-X-7600 

Please send me the information I have selected to the following address: 

Company/Department 

Name 

Street, Postal Code/City 

Telephone/Fax 

SIGUARD 

3RG784/3SF784 

Light Curtains 

Order No. 

E20001-A10-P873-X-7600 

Application Manual 


Order No. 

6ZB5 000-0AA02-0BA0 

CD-ROM 


Order No. 

E20001-D10-M103-X-7400 

Yes, I’m already being supported from Ms/Mr 

of the Siemens branch office in 

No, up until now I have had no contact with Siemens. 

I would like a sales person to visit me 

Subject to change without prior notice 09/04 | Order No. E20001-A20-P873-X-7600 | DISPO 27603 | 21CXXXX MK.PT.P7.SIGU.52.4.04 WS 0904X. | Printed in Germany | © Siemens AG 2004 

The information in this brochure only provides a general description and general performance features. For a specific application, this information will 

not always be applicable in the form described here. This information can also change due to ongoing product development. The required performance 

features are only binding if they have been expressly agreed upon in the form of a written contract. 

Siemens AG 

Automation and Drives 

Factory Automation Sensors 

P.O. Box 48 48, 90327 Nuremberg, Germany 

www.siemens.com/laserscanner 

www.siemens.com/safety 

www.siemens.com/fas

INTEGRATED

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