Minimum Monitoring Time For Safety-Related Communication Between F-Cpu And F-I/O - Siemens SIMATIC S7 System Manual

A.4.2 Minimum Monitoring Time for Safety-Related Communication between F-CPU and
F-I/O
PROFIsafe Monitoring Time TPSTO
To ensure that monitoring does not respond when no faults are present, the selected
PROFIsafe monitoring time TPSTO must be sufficiently large:
TPSTO > MAX(TCImax ; TCI + TDP_FD)* + 2 ☓ TDP_DLY + 2 ☓ TTR + 2 ☓ TSlave + TACK
+ TDP_SO + TSLAVE_SO
* Use the highest value
Definition of Times
Time
TCImax
TCI
TDP_FD
TDP_DLY
TTR
TSlave
TACK
TDP_SO
TSLAVE_SO
Safety Engineering in SIMATIC S7
System Manual, 04/2006, A5E00109529-05
A.4 F-Related Monitoring Times for S7 F/FH Systems
Definition
Maximum cycle time of the
relevant time interrupt OB
Configured cycle time of the
time interrupt OB
Maximum DP error detection
time
Additional DP time delay of a
PROFIBUS CP
(communications processor)
Maximum target rotation time for
the DP master system
Only relevant for distributed F-
I/O in ET 200M, ET 200S and
ET 200pro:
Maximum response time of
distributed I/O system, that is,
maximum delay by the IM and
its backplane bus
Maximum acknowledgment
time of F-I/O (for F-SMs: in
safety mode)
Maximum DP switchover time
Maximum switchover time for
the active communication
channel for switched I/O
(relevant for S7 FH Systems
only)
Monitoring and Response Times of F-Systems
Reference
"Minimum Monitoring Time for F-Cycle Time"
HW Config
In : Object properties for CPU,
"Time interrupt, Type"
HW Config
In : Object properties for DP
master system, Bus parameters, "H-
parameters" tab
HW Config
In : Object properties for CP,
"Operating Mode" tab
HW Config
In : Object properties for the DP
master system, Bus parameters
Refer to the manuals for F-I/O to learn about
how to calculate these times.
This time is provided in the technical
specifications for the F-modules or F-SMs in
ET 200S Fail-safe Modules
the
Fail-safe I/O Module
Signal Modules
manuals.
HW Config
In : Object properties for DP
master system, Bus parameters, "H-
parameters" tab
This time is provided in the technical
specifications for switched DP slaves (ET
ET 200M Distributed I/O System
200M) in the
manual.
ET 200eco
,
S7-300 Fail-safe
, and
A-11