Technical data

Appendix
27.8 Setting the Operating Behavior
Programming with STEP 7
Manual, 05/2010, A5E02789666-01 679
27.8.1 Changing the Behavior and Properties of Modules
Default Settings
• When supplied, all the configurable modules of the S7 programmable controller have default
settings suitable for standard applications. With these defaults, you can use the modules
immediately without making any settings. The default values are explained in the module
descriptions in the following manuals:
• "S7-300 Programmable Controller, Hardware and Installation" Manual
• "S7-300, M7-300 Programmable Controllers, Module Specifications" Reference Manual
• "S7-400, M7-400 Programmable Controllers, Module Specifications" Reference Manual
Which Modules Can You Assign Parameters To?
You can, however, modify the behavior and the properties of the modules to adapt them to your
requirements and the situation in your plant. Configurable modules are CPUs, FMs, CPs, and
some of the analog input/output modules and digital input modules.
There are configurable modules with and without backup batteries.
Modules without backup batteries must be supplied with data again following any power down. The
parameters of these modules are stored in the retentive memory area of the CPU (indirect
parameter assignment by the CPU).
Setting and Loading Parameters
You set module parameters using STEP 7. When you save the parameters, STEP 7 creates the
object "System Data Blocks" that is downloaded to the CPU with the user program and transferred
to the modules when the CPU starts up.