Siemens Simatic M7-400 Reference Manual page 610

Glossary
Declaration
Assigning variables (parameters or local data of a block, for example) with a
name, data type, comment, etc.
Default setting
The default setting is a sensible basic setting that is used whenever no other
value is used.
Destination CPU for interrupt
Parameter in STEP 7. If several CPUs are installed, the user can use this
parameter to select the destination CPU for hardware and diagnostic interrupts.
Diagnostic buffer
The diagnostic buffer is a buffered memory area in the CPU in which the
diagnostic events are stored in the order in which they occur.
For troubleshooting, the user can read out the exact error cause in STEP 7 (PLC
-> Module Information) from the diagnostic buffer.
Diagnostic data
All the diagnostic events that occur are collected in the CPU and entered in the
³ diagnostic buffer. If there is an error OB, it is started.
Diagnostic interrupt
Modules with diagnostics capability report system errors to the ³ CPU by means
of diagnostic interrupts. The operating system of the CPU calls OB 82 in the
course of a diagnostic interrupt.
Diagnostics
Generic term for ³ system diagnostics, process error diagnostics and
user-defined diagnostics.
Direct access
This is the direct accessing of the CPU by means of the ³ I/O bus to modules,
bypassing the ³ process image.
Glossary-4
S7-400, M7-400 Programmable Controllers Module Specifications
A5E00069467-07