Siemens SIMATIC PCS 7 CPU 410-5H System Manual page 129

5. Based on the technological specifications of your system, determine the following:
– Maximum permissible time during which there is no update of your I/O modules
6. Based on your user program, determine the following:
– Cycle time of the highest-priority or selected (see above) cyclic interrupt (T
– Execution time of your program in this cyclic interrupt (T
7. For each DP master system this results in:
T
8. For for each IO subsystem, this results in:
T
Note
If T
Possible remedies are shown below the following example calculation. Make appropriate
changes and then restart the calculation at 1.
9. Select the minimum of all T
This time is referred to below as TP15_HW.
10. Determine the share of the maximum inhibit time for I/O classes > 15 that is required by
the minimum I/O retention time (T
T
Note
If T
following example calculation. Make appropriate changes and then restart the calculation
at 1.
11. Using the information in Chapter Performance values for link-up and update
(Page 133), calculate the share of the maximum inhibit time for priority classes > 15 that
is required by the user program (T
Note
If T
following example calculation. Make appropriate changes and then restart the calculation
at 1.
12. The recommended value for the maximum inhibit time for priority classes > 15 is now
obtained from:
T
CPU 410-5H Process Automation
System Manual, 09/2014, A5E31622160-AB
(referred to below as T
(DP master system) = T
P15
(IO subsystem) = T
P15 PTO
(DP master system) < 0 or T
P15
= 50 ms + min. I/O retention time [2]
P15_OD
> T , stop the calculation here. Possible remedies are shown below the
P15_OD P15_HW
> T , stop the calculation here. Possible remedies are shown below the
P15_AWP P15_HW
MAX (T , T
P15 = P15_AWP P15_OD
).
PTO
- (2 x T + T + T
PTO TR WA
- (2 x T + T + T
max_Akt WA
(IO subsystem) < 0, stop the calculation here.
P15
(DP master system, IO subsystem) values.
P15
):
P15_OD
).
P15_AWP
) [3]
Link-up and update
8.3 Time monitoring
)
PROG
+ T + T
PROG DP_UM SLAVE_UM
+ T + T
PROG PN_UM Device_UM
)
WA
) [1]
) [1]
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