Siemens S7-400 Installation Manual page 295

Configuration
The configuration is the selection and putting together of the individual components
of a programmable logic controller (PLC).
Configuring
Configuring is the assigning of modules to racks or slots and (with signal modules)
addresses.
Connecting Clip
These are the clips with which the modules are mechanically interconnected within
an M7 module assembly.
Counters
Counters are an area in the system memory of the CPU. The contents of these
counters can be changed using STEP 7 instructions (for example, up counter,
down counter).
CP
³ Communications Processor
CPU
Central processing unit of the S7 or M7 programmable controller with processor,
arithmetic unit, memory, operating system, and programming device interface.
Cyclic Interrupt
A cyclic interrupt is generated by the S7-400 CPU periodically according to a
programmable time interval. A corresponding organization block is then executed.
D
Data Block (DB)
Data blocks are areas in the user program which contain user data. There are
shared data blocks which can be accessed by all logic blocks, and there are
instance data blocks which are associated with a particular function block (FB) call.
S7-400 and M7-400 Programmable Controllers Hardware and Installation
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Glossary
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