Addressing Signal Modules - Siemens SIMATIC S7-400 Configuration And Use Manual

Signal Modules of the S7-400
3.3

Addressing Signal Modules

Introduction
The address ranges of the S7-400 are adapted to the requirements for
easy-to-operate, high-performance controllers. In this chapter, you will learn which
address areas are used for SIMATIC S7 and how the addresses are assigned.
Address Ranges
The following address ranges are used for working with SIMATIC S7:
• I/O area
Inputs/outputs of digital and analog modules, function modules
• System data area
Parameter sets, diagnostic data
Access to the I/O Area of Digital Modules
The process image is accessed indirectly. The information from the inputs and to
the outputs is stored in the process image. Direct access is also possible here.
Access to the I/O Area of Analog Modules
The inputs and outputs are access directly. In other words, currently queued values
at the inputs are processed in the program and the results are immediately
forwarded to the outputs. Indirect access is also possible via the process image.
Access to System Data
System calls are integrated in the CPU. The system calls allow access to system
data for parameter sets and diagnostic data for each slot and are performed in the
user program.
Addressing with STEP 7
You can use STEP 7 to set the addresses for communicating with the modules. No
hardware settings using jumpers or switches are needed.
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Automation System S7-400 Configuration and Use
A5E00442711-02