Siemens SIMATIC S7-300 Series Reference Manual page 174

Glossary
Cycle time
The cycle time represents the time ³ a CPU requires for a single ³ user
program execution.
Data block
Data blocks (DB) are data areas in the user program which contain user data.
Global data blocks can be accessed by all code blocks while instance data
blocks are assigned to a specific FB call.
Data, static
Static data is data which can only be used within a function block. The data is
saved in an instance data block belonging to the function block. The data stored
in the instance data block is retained until the next function block call.
Data, temporary
Temporary data is local data of a block which is stored in the L stack during
execution of a block and which is no longer available after execution.
Delay Interrupt
³ Interrupt, Delay
Device master file
A Device Master File (GSD -file) contains all slave-specific characteristics data.
Standard EN 50170,
Volume 2, PROFIBUS, specifies the GSD file format.
Diagnostics
³ System diagnostics
Diagnostic Interrupt
Modules with diagnostic function use diagnostic interrupts to report detected
errors to the ³ CPU.
Glossary-4
PLC S7-300, CPU Specifications CPU 312 IFM to CPU 318-2 DP
A5E00111190-01