Glossary - Siemens Simatic S7-1500 Function Manual

Glossary

Backup CPU
Role of a CPU in the S7-1500R/H redundant system. If the R/H system is in RUN-Redundant
system state, the primary CPU guides the process. The backup CPU processes the user
program synchronously and can take over the process management if the primary CPU fails.
Cycle time
The cycle time represents the time a CPU requires to process the user program once.
Data block
Data blocks (DBs) are data areas in the user program that contain user data. The following
data blocks exist:
● Global data blocks which you can access from all code blocks.
● Instance data blocks that are assigned to a specific FB call.
Diagnostic interrupt
See "Interrupt, diagnostic"
Diagnostics
Monitoring functions include:
● The detection, localization and classification of errors, faults and alarms.
● Displaying and further evaluation of errors, faults and alarms.
They run automatically during plant operation. This increases the availability of systems by
reducing commissioning times and downtimes.
Diagnostics buffer
The diagnostics buffer represents a backup memory in the CPU, used to store diagnostics
events in their order of occurrence.
Distributed I/O system
System with I/O modules that are configured on a distributed basis, at a large distance from
the CPU controlling them.
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Cycle and response times
Function Manual, 10/2018, A5E03461504-AD