Is it possible to connect as many emergency stop pushbuttons as possible in series, in order to simplify a circuit (designed to Cat. 4)?

In a Category 4 architecture, a series connection of emergency stop pushbuttons is allowed because the emergency stop is only a secondary safeguard.

It is assumed that the emergency stop will only be operated in hazardous situations - and even then only one emergency stop pushbutton will be operated.
As part of the risk assessment in accordance with the industrial safety regulations, the operator must establish the intervals in which the safety functions must be inspected and the format that inspection will take.

Where is the limit in this case?
The limit lies in the required performance level. This is because the series connection of multiple safety components worsens the overall result. If you can reach the required PL by connecting the emergency stop pushbuttons in series, then the number is not inappropriate.

Is every switch rated as an SRP/CS in the context of the standard EN ISO 13849?
In the safety assessment you can connect all emergency stop switches in series, i.e. you only need to create one SRP/CS. However, as described above, the series connection may worsen the PL and so it may be possible to create several SRP/CS.

 

Headoffice

Pilz GmbH & Co. KG
Felix-Wankel-Straße 2
73760 Ostfildern
Germany

Telephone: +49 711 3409-0
E-Mail: info@pilz.de

Technical Support

Telephone: +49 711 3409 444
E-Mail: support@pilz.com

Americas

  • Canada: +1 888-315-PILZ (315-7459)
  • United States (toll-free): +1 877-PILZUSA (745-9872)
  • Brazil: + 55 11 4942-7032
  • Mexico: +52 55 5572 1300

Europe

  • Russia: +7 495 6654993
  • Spain: +34 938497433
  • Denmark: +45 74436332
  • Germany: +49 711 3409 444
  • Belgium: +32 9 321 75 70
  • Switzerland: +41 62 889 79 32
  • France (toll-free): +33 3 88104000
  • Austria: +43 1 7986263-444
  • Ireland: +353 21 4804983
  • Netherlands: +31 347 320477
  • Italy: +39 0362 1826711
  • United Kingdom: +44 1536 460866
  • Sweden: +46 300 13990 / +45 74436332
  • Turkey: +90 216 577 55 52
  • Finland: +358 10 3224030 / +45 74436332
  • Portugal: +351 229 407 594

Asia Pacific

  • New Zealand: +64 9 6345350
  • Thailand: +66 210 54613
  • Japan: +81 45 471 2281
  • Australia (toll-free): +61 3 9560 0621 / 1300 723 334
  • China: +86 400-088-3566
  • South Korea: +82 31 778 3390
  • Taiwan: +886 70 1015 0068
  • Singapore: +65 6829 2920
Was this article helpful?