Safety
Fail-Safe Systems
7-8 A5E00085588-03
7.4 Monitoring Times
7.4.1 Configuring the Monitoring Times for F/FH Systems
Rules for Monitoring Times
When you configure the monitoring times, you must take into consideration both
the availability and the safety of the F/FH system:
• Availability: To ensure that the temporal monitoring is not triggered when there
is no error, the monitoring times selected must be sufficiently long.
• Safety: To ensure that the process safety time is not exceeded, the monitoring
times selected must be sufficiently short.
Monitoring Times of an F System
You must configure the following monitoring times for the F-system:
• Parameters of the fail-safe blocks:
Monitoring Block Parameter
Monitoring of the F cycle time of the cyclic interrupt OB
that contains the safety program
F_CYC_CO MAX_CYC
Monitoring of safety-related communication between F
run-time groups
F_R_R
F_R_BO
TIMEOUT
Monitoring Safety-Related Communication Between
CPUs
F_RCVR,
F_RCVBO
F_SENDR,
F_SENDBO
TIMEOUT
• Parameters of the F-I/Os
Monitoring Parameter
Monitoring Safety-Related Communication
Between F-CPU and F-I/Os via PROFIsafe
Monitoring time (properties dialog in
HWCONFIG)
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