EN ISO 13849

The new approach for safety-related machine control systems

michael.schaefer@dguv.de

Slide 2

Safety function and control system

How expensive shall a control system be?

What makes a control system safe?

Slide 3

„Ouality” criterion of a safety function

The safety function reduces the risk!

a) Risk shall be reduced by very little effort.

b) Risk shall be reduced by little effort.

c) Risk shall be reduced by medium effort.

d) Risk shall be reduced high effort.

e) Risk shall be reduced very high effort.

a

b

c

de

RISK

Slide 4

Safety functions and SRP/CS

Safety functions are carried out by safety-related parts of a control system

(SRP/CS) and shall reduce the associated risk to an acceptable level

Input Logic Output

sense compute actuate

Examples from machinery

• safe stop, safe position, safely limited speed

Slide 5

Risk estimation by risk graph

S1 slight (normally reversible injury)

S2 serious (normally irreversible injury or death)

F1 seldom-to-less-often and/or exposure time is short

F2 frequent-to-continuous and/or exposure time is long

P1 possible under specific conditions

P2 scarcely possible

Slide 6

Safety–related Parts of Control System SRP/CS

• Robustness against Environment

• Robustness against operation

• possibly now constructional faults

• good reliability

• trouble indication

• reaction in case of faults (safe state)

• no further hazards by using SRP/CS

• ….

Slide 7

Ability of a SRP/CS to carry out a safety to achieve the

required risk reduction.

Property of a device!

„Ouality” criterion of a SRP/CS

PL without r

Slide 8

Simple Example for S(M)Es

Hydraulic

valves

Category 1Category 3Category 2 type 2

Light curtain

Electronical

Control

logic

hydraulic cylinder

movement

hazardous

Slide 9

Linear combination of more than one SRP/CS

SRP/CS 1

PL

SRP/CS 2

PL

SRP/CS 3

PL

SRP/CS

PL

PL low N low PL

> 3 = > nonea

3 = > a

> 2 = > ab

2 = > b

> 2 = > bc

2 = > c

> 3 = > cd

3 = > d

> 3 = > de

3 = > e

c

d

c

?c

Slide 10

Free tools for application of EN ISO 13849

• PLC-Disc

• Determination of the PL using designated architectures

• BGIA-Report 2/2008e (German version: 2/2008)

• Guideline for use of EN ISO 13849

• Many control circuits examples

• Software tool SISTEMA (German/English/…)

• Supports use of designated architectures

• Dynamic calculation of PL and PFH

• Report function

• Manufacturers data bases

www.dguv.de/ifa/13849e

Slide 11

SISTEMA-User

Jan. 08 Jan. 09July 08 July 09

5.000

0

10.000

15.000

20.000

25.000

Jan. 10

Date: 24.08.2010:

- 20300 registered User

- 60000 Downloads

Slide 12

Origin of registriered SISTEMA-user

.de Germany 7630

.com .net Companies 7676

.nl .be .lu Benelux 963

.at Austria 493

.ch Switzerland 373

.se .dk .fi Scandinavia 358

.it Italy 348

.uk UK 263

.fr France 197

.jp Japan 195

Today 20300 registered user

Slide 13

Provider of Data for Components etc:

Leuze electronic GmbH Co. KG

Pepperl Fuchs GmbH

Pilz GmbH & Co. KG

Pizzato Elettrica S.r.l.

REER S.p.a.

riese electronic gmbh

Rockwell Automation, Inc

K.A. Schmersal GmbH

Schneider Electric Automation GmbH

SEW EURODRIVE

SICK AG

wenglor sensoric gmbh

Wieland Electric GmbH

SISTEMA libraries:

Balluff GmbH

BBH Products GmbH

Bernecker & Rainer Industrie-Elektronik

Ges.m.b.H.

Bihl Wiedemann GmbH

Bosch Rexroth AG

Eaton Electrical Sector EMEA, Moeller

GmbH

EUCHNER GmbH Co. KG

Fiessler Elektronik GmbH

Gunnebo Troax AB

JOKAB SAFETY AB

Lenze Automation GmbH

Up to 100 parts , components, elements, sub systems for each library!

Another 30 companies are preparing libraries!

http://www.leuze.de/downloads/las/software/sistema_DB.zip

Slide 14

Data within EN 13849-1

Types of Semiconductors and passive components:

Slide 15

Do you fulfill requirements of EN 954-1:1996 and 13849-2

(well-tried components, basic and well-tried safety principles)?

Requirements known since more than 10 (!) years

Then …

Slide 16

… use Data of table C.1 within EN 13849-1

This table overtakes conventional

well known technologies to

the new world

Slide 17

Well tried?

Proven in use?

Proven in use by technology?

Example:

Pneumatic mini valves

not acc. EN ISO 13849-2:

How to estimate safety?

Slide 18

European Valve

Slide 19

North American Valve

Slide 20

Asiatic Valve

Slide 21

Risk graph of ISO/TR 14121-2 (informative)

Slide 22

W-parameter or O-Parameter

Process -> O-Parameter

Safety-related control

Depending on the probability of Occurrence O1, O2 or O3

Slide 23

What determines O?

1. probability of standard control system (see eg. chemical plants)

2. probability that a process will develop to a hazard by

• physical reason

• chemical reason

• etc.

3. experience in the process (application)

How do we determine O in a justifiable way?

1. Quantify the probability of standard control system

2. Quantify probability that a process will develop to a hazard by

• physical reason

• chemical reason

• etc.

3. justify and Quantify experience in the process (application)

Slide 24

Estimation of O by accident statistics?

Problems to think about:

1. Machines in history have protective devices since a long time

so statistics is wrong for a justifiable estimation of O.

2. The frequency of accidents at machinery without protective devices

is therefore not properly documented.

3. Technology and reliability of standard controls has changed

within the last decades.

Slide 25

Solution: Estimation of O by application experts!

The only way to justify a certain O in a C-Standard is to have:

• good knowledge of the process (application) and/or

• of the probability of failure of the standard control.

This cannot be supported by a generic B-Standard as EN ISO 13849-1

Therefore EN ISO 13849-1 has to assume

a worst case O-Parameter

The risk graph is informative,

to deviate from the required PL

a C-Standard may deviate from ANNEX A

Slide 26

Conclusion:

1. The standard provides simple way for small enterprises.

2. There are a lot of data available by EN ISO 13849-1 itself and by

component manufacturer.

3. There are already widely used tools in different languages

to help SMEs

4. The technology itself (mechanics, hydraulics, pneumatics)

is no prove for “well-tried” or “proven in use”

5. O-Parameter should be carefully estimated

Slide 27

Future tasks:

1. Improve readability of EN ISO 13849-1

2. Give more aids in the standard and correct the experienced difficulties

3. Give a hint in Annex A (Risk Graph) that EN ISO 13849 uses

worst case assumption.

4. Give more aid for developing the safety-related block diagram

5. Standardization of a reliability data exchange format (VDMA)

6. Additional application aids see:

www.dguv.de/ifa/13849

7. VDMA-support by training of members

8. VDW support for typical safety functions of machine tools

9. ZVEI-support delivering additional data

http://www.dguv.de/ifa/13849

Slide 28

Promise within the next weeks:

SISTEMA Cookbook

to support application of the standard and

SISTEMA