Siemens S5-135U/155U System Manual page 486

Analog Input/Output Modules
Addressing for
However, analog input modules and analog output modules may be given the
Cyclic/Selective
same address with cyclic sampling because they are distinguished by the user
Sampling program. This is not possible with selective sampling.
For cyclic sampling, you can address the module in the address range from 0
to 255, and for selective sampling from 128 to 255. For selective sampling,
you can also use the address range from 0 to 127 after appropriate
programming in DB 1 of the user program.
Example:
On an analog output module with 8 outputs with start address 144 (IB 144 =
output byte 144), output channel 7 is to be scanned by the program.
Step
1
2
3
9-104
Action
Affix the self-adhesive label with address 160 on the free field under the
addressing switch on the module. ADB 4 and ADB 7 are marked on the
label.
Press the appropriate rockers of the addressing switch down on the side
marked by a dot on the module cover. Set the other rockers to the opposite
setting. This sets the start address of the module.
4
ADB 4 and ADB 7 results in 2
Enter the address 144 + 7 x 2 = 158 in the program for input channel 7.
7
+ 2 = 16 + 128 = 144
System Manual
C79000-G8576-C199-06