Addressing the S7-400
3-4
S7-400 and M7-400 Programmable Controllers Hardware and Installation
A5E00069481-04
3.2
How to Determine the Default Address of a Module
Default Addressing
You determine the default address of a module from the number of the slot of the
module in the CR.
The algorithms used to calculate the default address are different for analog and
digital modules.
The following figure shows the numbering of slots in a rack with 18 slots. You can
also read off the slot numbers directly from the rack.
1
2
3
4
5
6
7
8
9
10
11
12 13
14 15
16
17 18
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
Default Addresses of Digital Modules
On the S7-400, the default addresses for digital modules start from 0 (First slot in
the central rack which is usually occupied by the power supply module) up to 68
(18th slot).
The algorithm used to calculate the default address of a digital module is:
Default address = (slot number - 1) x 4
Example
The default address of a digital module in the 12th slot is as follows:
Default address = (12 - 1) x 4 = 44
