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Entry type: Application example Entry ID: 67634251, Entry date: 07/05/2018
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Specification of Limit Values for Safely Limited Speed (SLS) from a Non-Safety HMI

  • Entry
  • Associated product(s)
The SLS value is to be specified using a non-safety HMI and transferred to the drive via an F-CPU. As the connection between the HMI and the F-CPU is considered to be non-safe, data corruption could result in an unwanted SLS value being transferred to the F-CPU and then to the drive, which can cause dangerous situations.

Solution
An HMI allows the operator to set a new SLS value. This value is deliberately modified in the HMI. Aside from the SLS value, this modification generates two additional values that are also transferred to the F-CPU. These modified values are used to rule out data corruption.

The modifications by the HMI are undone in the safety program. If the two remodified values match the transferred SLS value, data corruption can be ruled out.



Figure 1


If any data corruption is detected, this information is displayed on the HMI. Only if the three values are identical (correct data transfer) will the HMI display the SLS value to the user for release and the new SLS value can be released by the operator.

Then the new SLS value is transferred from the controller to the drive via the fail-safe PROFIsafe PROFINET profile.



Figure 2

The safety concept described here is suitable to achieve SIL 3 according to IEC 62061 or PL e according to ISO 13849-1.


Advantages
The solution presented here offers the following advantages:

  • User-friendly transfer of safety-related configuration data for the drive using a non-safety HMI.
  • The safety concept can also be applied to other tasks.
  • The F-CPU and the drive with safety functions are certified safety components, i.e., an SLS value in the F-CPU is safely transferred to the drive with safety functions.
  • Planning reliability due to TÜV assessment (see “Downloads”).


Downloads
V3.0 for TIA Portal V14 SP1 and higher
  Documentation (1,5 MB)
 Registrierung notwendig  Example project for TIA Portal V15 (8,9 MB)
 Registrierung notwendig  Example project for TIA Portal V14 SP1 (6,9 MB)
  TÜV report (631,6 KB) 

V2.0 for TIA Portal V13 SP1
  Documentation (859,4 KB)
 Registrierung notwendig  Example project (25,2 MB)
  TÜV report (485,8 KB)

V1.0 for STEP 7 V5.5 with Distributed Safety
  Documentation (626,0 KB)
 Registrierung notwendig  Example project (2,9 MB)
  TÜV report (948,3 KB)


Last changes

  • Upgrade of the project to TIA Portal V15 and V14 SP1
  • Addition of a data buffer to avoid possible data corruption errors
  • Revision of the visualization on basis of the HMI Template Suite 91174767 


Additional Keywords
failsafe, panel, WinCC, Safety Integrated, F-PLC, safety integrity level, performance level

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
https://www.siemens.com/cybersecurity#Ouraspiration.