Information On The Simatic S7-300 Automation System - Siemens SIMATIC S7-300 Manual For Migrating

3 SIMATIC S7-300/S7-400 and SIMATIC S7-1500 System Architecture
3.1.1

Information on the SIMATIC S7-300 automation system

The SIMATIC S7-300 automation system is a programmable controller for factory
automation/engineering in the OEM sector. The S7-300 system has a modular
design and consists of the following components:
Power supply modules
Central processing units
Input and output modules
Signal preprocessing modules
Communications processors
Function modules
These SIMATIC S7 components are mounted to an aluminum rack. This rack is
used to mechanically fasten all modules. In order to enable communication with the
following modules, bus connectors are used on the back.
Expansion options
If necessary, the connection capacity of the central rack can be increased by
expansion devices (IM 360 S, IM 361 R, 365 S-R). Appropriate interface modules
connect the central controller to the expansion racks.
Memory concept
The S7-300 is programmed using the STEP 7 programming software from
Siemens. The control program can be transferred to the central processing unit
(CPU) via a programmer.
The user program is saved in the load memory of the CPU. Since the CPU does
not have an internal load memory, a memory card (MMC) is used for this purpose.
Since the program cannot be stored in a volatile manner on the MMC, work can be
carried out without a buffer battery. The Micro Memory Card is mandatory for
operating the CPU. The size of the internal program memory differs depending on
the CPU type.
Note
The first generation of S7-300 CPUs still worked with a memory card. Here it
was necessary to provide a buffer battery for the CPU to still preserve the
program in the event of a power failure.
Information on the S7-300 automation system can be found in the device
Note
manual:
https://support.industry.siemens.com/cs/ww/en/view/8859629
Migration S7-300/S7-400 nach S7-1500
Entry ID: 109478811, V1.1, 05/2017
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