×
Siemens Industry Online Support
Siemens AG
Entry type: FAQ Entry ID: 41570, Entry date: 09/24/2001
(0)
Rate

Parallel interconnection of outputs with S7-21x and S7-22x

  • Entry
  • Associated product(s)


QUESTION:
Can I interconnect the DC outputs for the S7-21x and S7-22x CPUs in parallel.

ANSWER:
CPU outputs are normal PNP transistors and should not be interconnected in parallel because of the asymmetry in the load and the different switch-on delays.

You can solve the problem by using a CPU 215, 216, 221, 222, 224, 226, 226XM or an EM223 expansion module.
All outputs of these units have FET transistors which can support a wired OR connection.

Keywords:
Wiring

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.