Siemens SIMATIC S7-400 Installation Manual page 210

Glossary
C
Central module
Programmable S7-400 module with MPI interface, controls the automation tasks.
Chassis Ground
The chassis ground comprises all interconnected inactive parts of an apparatus,
which even in case of a fault cannot take dangerous touch voltages.
Cold restart
Restart of an automation system and its user program after all dynamic data ( tags
of the I/O image, internal registers, timers, counters etc. and the corresponding
program elements) were reset to default. A cold start may be triggered
automatically (for example, due to power failure, loss of dynamic data in memory).
Communications Processor
Communications processors are modules for point-to-point and bus connections.
Compress
The PG online function "Compress" is used to shift all valid blocks in the RAM of
the CPU evenly and without any gaps to the beginning of the user memory. All
gaps caused by deleting or correcting blocks are thus removed.
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.
Consistent data
Data associated with each other in the same context and which may not be
separated
All values of analog modules must be treated as consistent data, for example. That
is, a value read at different times from an analog module may not be corrupted.
Glossary-2
Automation System S7-400 Hardware and Installation
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