Entry type: FAQ, Entry ID: 14198063, Entry date: 07/07/2016

How can you combine fail-safe and standard modules in the ET 200 stations?

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With ET 200S and ET 200M you can use fail-safe and standard modules combined. Additional measures have to be taken for some modules in this respect.

The following informationen refers as given below:

  • With SIL to the IEC 62061:2005 / IEC 61511:2003
  • With PL to the ISO 13849-1:2006

Combination of Standard and Fail-safe Modules with ET 200S
If you use the standard output module of the type DC24V/0.5A in combination with power module PM-E F for safe switch-off, you can attain SIL 2PL d/category 3. The standard output modules you can use are given in Entry ID: 39198632.

If you want to have safe switch-off done via a fail-safe output module (F-DO), you can combine standard and fail-safe input/output modules and attain SIL 3/PL e/category 4. However, make sure that you use an appropriate power module PM-E (6ES7138-4CB11-0AB0, for example). The SIMATIC Selection Tool (see Entry ID: 26484854) will help you with this.

Combination of standard and fail-safe modules with ET 200M
Refer also to the manual "Fail-safe Signal Modules" (Entry ID 19026151, section 2.3 Configuration with F-SMs in Safety Mode).
You can also use a combination of fail-safe and standard input/output blocks in an ET 200M station.

The isolation module must be used for SIL3/Cat.4/PLe applications:

Only when using

  • SM336, AI 6 x 13 bits (6ES7336-1HE00-0AB0)
  • SM326, DI 8 x NAMUR (6ES7326-1RF00-0AB0 and higher)
  • SM326, DO 10 x DC 24V/2A (6ES7326-2BF01-0AB0)
  • SM326, DI 24 x DC 24V (up to 6ES7326-1BK01-0AB0)
  • SM326, DO 8 x DC 24V/2A PM (6ES7326-2BF40-0AB0)
and if
  • The F-SMs are used centrally in an S7-300.
  • The PROFIBUS DP is set up with copper cable.
  • The PROFIBUS DP is set up with fiber optic cable with IM 153-2FO and you require combined operation of standard and the above-mentioned F-SMs in an ET 200M.

The isolation module separates the potential groups of the fail-safe and standard modules. In this case, the standard IO modules must be slotted to the left and the fail-safe modules to the right of the isolation module.

The following successor modules can be implemented also without isolator module up to SIL3/Cat.4/PLe applications:

  • SM326, DI 24 x DC 24V (6ES7326-1BK02-0AB0)
  • SM336, AI6 x 0/4...20mA HART (6ES7336-4GE00-0AB0)
  • SM326, DO 10 x DC 24V/2A PP (6ES7326-2BF10-0AB0)
  • SM326, DO 8 x DC 24V/2A PM (6ES7326-2BF41-0AB0)

Additional Keywords
Safety Integrated, Mixed operation, PROFIsafe, Distributed Safety mixed operation, Fail-safe, Isolation module, Power module, ET 200 family, DI, DQ, Configuration editor