Addressing Analog Modules - Siemens Simatic S7-300 CPU 31xC Series Installation And Operating Instructions Manual

7.2.3

Addressing analog modules

This section describes how to address analog modules. You need this information in order to
be able to address the channels of the analog modules in your user program.
Addresses of analog modules
The analog input or output channel is always assigned a word address. The channel address
is based on the module start address. When the first analog is located in slot 4, its default
start address is 256. The start address of each further analog module increments by the
count of 16.
An analog I/O module has the same start addresses for its input and output channels.
An example of analog modules
The example in the figure below shows you which default channel addresses are derived for
an analog module located at slot 4. As you can see, the input and output channels of an
analog I/O module are addressed starting at the same address, namely the module start
address.
Slot number 3 is not assigned, because the example does not contain an interface module.
Slot number
See also
Slot-specific addressing of modules (Page 7-1)
S7-300, CPU 31xC and CPU 31x: Installation
Operating Instructions, Edition 08/2004, A5E00105492-05
SF
SIEMENS
BUSF
DC5V
FRCE
RUN
STOP
PS
1
2
7.2 User-specific addressing of modules
CPU
SM (analog module)
Inputs
Channel 0: Address 256
Channel 1: Address 258
:
:
Outputs
SM
Channel 0: Address 256
Channel 1: Address 258
:
:
4
Addressing
7-5