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Siemens Simatic S7-400 User Manual

Page 610

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Glossary

Glossary-4

S7-400, M7-400 Programmable Controllers Module Specifications

A5E00069467-07

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

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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

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system diagnostics, process error diagnostics and

user-defined diagnostics.

Direct access

This is the direct accessing of the CPU by means of the

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I/O bus to modules,

bypassing the

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process image.

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