Siemens Industry Online Support
Siemens AG
Entry type: Application example Entry ID: 28609440, Entry date: 10/16/2008

Safety: Implementation of a safety function (SIL 3 / PL e) with PROFINET IO via IWLAN

  • Entry
  • Associated product(s)

Many modern automation systems are characterized by the following features:

  • S7 CPU and ET 200 distributed I/O, connected over the Industrial Ethernet / PROFINET IO bus
  • Safety program and standard program in the same S7 CPU
  • Normal signals (e.g. Switch motor on) and safety-related signals (e.g. Emergency-off motor) are transferred over the same bus

For many applications, wireless communication is more cost-effective than communication using cable. In some cases, it is the only way of connecting an S7 CPU with distributed ET 200 stations. This applies, for example, to communication between moving parts of an automation system or between areas that are difficult to access.

The following functionality is implemented using wireless (PROFINET IO over IWLAN):

  • Normal switching duty of a motor (start, stop)
  • Safety-related motor switch-off (emergency stop)
  • Safety function (emergency-stop) in SIL 3 / PL e

Standard and safety-related communication thus takes place via IWLAN. The safety-related communication complies with SIL 3 / PL e. This is enabled by PROFIsafe. The following hardware components are used in the functional example, as well as standard components:

  • Safety-related components: SIMATIC Safety Integrated for Factory Automation
  • Components for IWLAN: SCALANCE W


Content of Downloads


28609440_as_fe_i_016_v10_iwlan_en.pdf ( 2253 KB )
Archieved STEP 7 project
28609440_as_fe_i_016_v10_code_iwlan.zip ( 578 KB )
One configuration file for the access point, and one configuration file for the ethernet client module
28609440_as_fe_i_016_v10_conf_iwlan.zip ( 5 KB )





10/2008 first edition

Filter criteriea:
CPU315F-2 PN/DP, access point, SCALANCE W788-1PRO, ethernet client module, SCALANCE W744-1PRO

Security information
In order to protect technical infrastructures, systems, machines and networks against cyber threats, it is necessary to implement – and continuously maintain – a holistic, state-of-the-art IT security concept. Siemens’ products and solutions constitute one element of such a concept. For more information about cyber security, please visit
Rate entry
Requests and feedback
What do you want to do?
Note: The feedback always relates to the current entry / product. Your message will be forwarded to our technical editors working in the Online Support. In a few days, you will receive a response if your feedback requires one. If we have no further questions, you will not hear from us.