Siemens Industry Online Support
Siemens AG
Entry type: FAQ Entry ID: 22797465, Entry date: 09/16/2014

MICROMASTER 4 (MM4): addressing the digital inputs, outputs using PROFIBUS

  • Entry
  • Associated product(s)
Applies to MM4 with PROFIBUS options module

How can I address or control the digital inputs or outputs using PROFIBUS?

The digital inputs (DIN) can be read-out via the DP by setting parameter P2051 to r722 (CO/BO values, digital inputs).

The state of digital outputs (DOUT) can be interrogated in the same way. In this case, the value of parameter P2051 should be set to r747 (CO/BO values, digital outputs).

In order to control the digital outputs DOUT of MICROMASTER (440 & 430 & 420) via DP bus, the bits of control word 1 and control word 2 that are not used can be utilized for this purpose. These are the following bits: 2090.12, 2091.6, 2091.7, 2091.10, 2091.14.

The digital outputs must then be interconnected with the bits, e.g.:

P0731 = 2090.12
P0732 = 2091.6
P0733 = 2091.7

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