Siemens Industry Online Support
Siemens AG
Entry type: Application example Entry ID: 49221879, Entry date: 02/15/2017

Safety position, standstill, direction and speed detection

  • Entry
  • Associated product(s)
These movements must be safely detected to reliably protect the operator from dangerous machine movements.

In many cases, safe standstill detection is indispensable. Safe speed limits may be required for servicing and setup purposes. Nevertheless, hazards can also occur if a desired position is not reached or a prohibited position is approached.

This leads to the question how machine movements can be detected whilst keeping safety in mind.

For the safe detection of machine movements, SIEMENS drives with integrated safety functions (for example, SINAMICS G120) offer various applications.

Another option is the use of safe position encoders. In combination with a SIMATIC F-CPU, these securely detected values of the F position encoder can be processed further and corresponding responses can be triggered. This application example describes the application of such an encoder.

The function example shows you how you can easily integrate an F position encoder in PROFINET. As a result, you can realize a number of safety-relevant issues with the F-CPU.

In this example, the following issues are introduced:

  • Safe standstill detection
  • Safely limited speed (SLS)
  • Safe direction detection
  • Safe position detection

Figure 1

Providers of failsafe position encoders are, for example:

The present example was realized with the fail-safe position encoder CDV75M by TR Electronic (SIL CL 3 / PL e / cat 4).

In terms of safety, these applications fulfill a safety integrity level up to SIL 3 in accordance with IEC 62061 or PL e in accordance with ISO 13849-1.

Documentation and Example Project
  Documentation (1,1 MB)
 Registrierung notwendig  Example project for STEP 7 V13 SP1 (13,4 MB)
 Registrierung notwendig  Evaluation of the safety function as SET project (6,6 KB)

 Registrierung notwendig  Documentation V1.0 for STEP 7 V5.5 and Distributed Safety (606,6 KB)
 Registrierung notwendig  Example project V1.0 for STEP 7 V5.5 and Distributed Safety (1,1 MB)

Last Changes
Migration of the application example to STEP 7 V13
Migrating the controller to S7-1500
Replacing the F position encoder with PB with an F position encoder with PN
Correction in the Archive files: Change adress I7.0 to I8.0

Additional Keywords

Encoder, SLS, Safely Limited Speed, absolute encoder, incremental encoder

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
Support to the statistics
With this function the IDs found are listed according to number (format .txt).

Generate list
Copy URL
Display page in new design
mySupport Cockpit