Glossary
Glossary-3
Automation System S7-400 Hardware and Installation
A5E00850741-01
Counters
Counters are an area in the system memory of the C PU. The contents of these
counters can be changed using STEP 7 instructions (for example, up counter,
down counter).
CP
→ Communications Processor
CPU
Central processing unit of the S7 programmable controller with processor,
arithmetic unit, memory, operating system, and programming device interface.
Cycle time
Thetimea→ CPU requires to execute the → user program.
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 c ontain 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.
Data, Static
Static data are data which are used only within a function block. These data are
stored in an instance data block belonging to the function block. The data s tored in
the instance data block are retained until the next function block call.
Data, Temporary
Temporary data are local data of a block that are stored in the L stack during
processing of the block and that are not retained after processing.
Default Setting
A default setting is an expedient basic setting which is always used w hen no other
value is preset by a parameter.
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