Siemens S7-400 How to Determine the Default Address of a Channel, Channel on a Digital Module

Addressing the S7-400

3.3How to Determine the Default Address of a Channel

Channel on a Digital Module

A channel on a digital module is addressed bit-wise. For a digital input module with 32 inputs, four bytes (starting with the default address of the module) are used to address the inputs, and for a digital input module with 16 inputs, two bytes are used. Bits 0 to 7 in these bytes are then reserved by the individual inputs (from top to bottom).

This is clarified by the following figure with the example of a digital input module with 32 channels at slot 12 (default address 44). With a digital output module, the first character is a Q instead of an I.

Channel addresses

I 44.0

I 44.1

I 44.2

I 44.3

I 44.4

I 44.5

I 44.6

I 44.7

I 45.0

I 45.1

I 45.2

I 45.3

I 45.4

I 45.5

I 45.6

I 45.7

I 46.0

I 46.1

I 46.2

I 46.3

I 46.4

I 46.5

I 46.6

I 46.7

I 47.0

I 47.1

I 47.2

I 47.3

I 47.4

I 47.5

I 47.6

I 47.7

3-6	Automation System S7-400	Hardware and Installation
		A5E00850741-01