Safety instrumented system SIS (SAFETY LOOP)

  • As a rule, alarm equipment performs a safety protection function on machines and systems. Therefore, the consequences of an error in the signaling devices always present a potential risk if not seen.
  • A hazard graph is not only an important element for the classification of the system or plant, it also clearly illustrates how complex the preliminary work is for the realisation and implementation of projects.

Functional safety EN ISO 13849-1 (PL)

Machinery directive 2006/42/EG has been valid since the 1st January 2010. It was signed on 17 May 2006 and published in the Official Journal of the European Union (OJ L 157) on 9 June 2006. Two safety standards became effective with the machinery directive. On the one hand, DIN EN ISO 13849-1, which replaces Norm DIN EN 954-1 of the old machinery directive 98/37/EG. On the other hand DIN EN 62061.

Objective of these safety norms is to minimise risks in the operation of machines. Therefore, the requirements for the certification of products for machine and plant manufacturers were increased. Probability considerations, amongst other things, have an impact on the regulation of the safety of components. In order to keep the existing residual risk of a machine or plant as low as possible, alarm devices which have a high functional safety are required. They should also alert about danger via visual or audible warning signals.

Risk assessment

Risk parameters

S – Severity of the injury     

  • S1 = minor injuries (normally reversible)     
  • S2 = serious injuries, including death (normally irreversible)

F – Frequency and/or length of exposure to the hazard     

  • F1 = rarely to more often and/or short periods     
  • F2 = frequently to continuously and/or long duration

P – Possibilities to avoid danger     

  • P1 = possible under certain conditions     
  • P2 = barely possible

Publications / Applications

Description Language Type Size Download

SIL/PL fundamentals for machine technology

  • English
pdf 5.7 MB Download

Control example „Machinery Start-up“

  • English
pdf 270 KB Download

Control example „Muting Operation“

  • German
pdf 430 KB Download

Brochures / Poster

Description Language Type Size Download

Facilitate norm-conforming Functional Safety

2-page A1 poster

  • English
pdf 2.5 MB Download

Safer running of processes and risk minimisation

in the operation of plants and machines Safety-related sounders and flashing lights (Edition 15)

  • English
pdf 1.1 MB Download

Functional Safety info sheet

  • English
pdf 1.0 MB Download

Software assistant SISTEMA

Control safety of machines – easily calculated.

The manufacturer-independent calculation tool SISTEMA, from the Institut für Arbeitsschutz (IFA) (German Occupational Health and Safety Department) helps by the evaluation of safety-related control systems according to EN ISO 13849-1 and simplifies risk analysis.

The Windows tool builds the structure of the safety-related control components (SRF/CS, Safety-Related Parts of a Control System) based on the so-called provided architectures and calculates the reliability values at various detailed levels including the achieved Performance Level (PL).

Please click here .... to proceed with the download of the Pfannenberg SISTEMA library. 

Further information and the SISTEMA software download directly from IFA (German Occupational Health and Safety Department).

The SISTEMA Cookbook

Before the machine designer begins the calculation of the Performance Level, he/she must create the schematics on a safety-related block diagram, which depicts the design of the safety function in function channels and the components to be tested. The SISTEMA cookbook 1 covers this unusual and difficult step of the abstract, as well as the following step, which is the transfer of the blocks into SISTEMA and the entering of their characteristic values.

Download the SISTEMA Cookbook 1

Libraries can be managed from a central database server in your company and be used by several SISTEMA users simultaneously. The new SISTEMA cookbook 2 describes the installation of these servers and handling in SISTEMA.

Download the SISTEMA Cookbook 2

Running several instances of SISTEMA in parallel (terminal server).

Download the SISTEMA Cookbook 3

When the designated architectures don't match.

Download the SISTEMA Cookbook 4