Siemens SIMATIC CP 340 User Manual page 195

Process image
The process image is a special memory area in the programmable controller. At the start of
the cyclic program the signal states of the input modules are transmitted to the process
image of the inputs. At the end of the cyclic program the process image of the outputs is
transmitted as signal state to the output modules.
Programmable Controller
A programmable controller is a stored-program control consisting of at least one CPU,
various input and output modules, and operating and monitoring devices
Protocol
All communication partners involved in data transmission must follow fixed rules for handling
and implementing the data traffic. Such rules are called protocols.
S7-300 backplane bus
The S7-300 backplane bus is a serial data bus via which the modules communicate with
each other and via which they are supplied with the necessary voltage.
Software
Software refers to the entirety of all programs that are used on a computing system. The
operating system and user programs belong to this.
START-UP
The START-UP operating mode forms the transition from STOP mode to RUN mode.
STEP 7
STEP 7 is the programming software of SIMATIC S7.
System blocks
System blocks are different from other block in that they are already integrated into the S7-
300 system and are available for already defined system functions. There are system data
blocks, system functions and system function blocks.
PtP coupling and configuration of CP 340
Manual, 04/2011, A5E00369892-03
Glossary
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