Major Components Of The S7-200 Micro Plc; S7-200 Cpu - Siemens SIMATIC S7-200 System Manual

1.2

Major Components of the S7-200 Micro PLC

An S7-200 Micro PLC consists of an S7-200 CPU alone or with a variety of
optional expansion modules.

S7-200 CPU

The S7-200 CPU combines a central processing unit (CPU), power supply, and
discrete I/O points into a compact, stand-alone device.
The CPU executes the program and stores the data for controlling the
automation task or process.
The digital inputs and outputs are the system control points: the inputs monitor
the signals from the field devices (such as sensors and switches), and the
outputs control pumps, motors, or other devices in your process.
The power supply provides electrical power for the CPU and for any expansion
module that is connected.
The communications port(s) allow you to connect the CPU to a programming
device or to other devices.
Status lights provide visual information about the CPU mode (RUN or STOP),
the current state of the local I/O, and whether a system fault has been
detected.
Additional I/O points can be added to the CPU with expansion modules. (The
CPU 221 is not expandable.)
Higher performance communications can be added with expansion modules.
Some CPUs provide a real-time clock as a built-in feature, while other CPUs
have an optional real-time clock cartridge.
An optional plug-in serial EEPROM cartridge provides a means to store CPU
programs and transfer programs from one CPU to another.
An optional plug-in battery cartridge provides extended retention of data
memory in RAM.
S7-200 Programmable Controller System Manual
A5E00066097-02
Introducing the S7-200 Micro PLC
1-5