Siemens CPU 410-5H Process Automation System Manual page 117

8. For for each IO subsystem, this results in:
9. Select the minimum of all T
10.Determine the share of the maximum inhibit time for I/O classes > 15 that is required by
11.Using the information in Chapter Performance values for link-up and update
12.The recommended value for the maximum inhibit time for priority classes > 15 is now
Example of the calculation of T
In the next steps, we take an existing system configuration and define the maximum
permitted time span of an update, during which the operating system does not execute any
programs or I/O updates.
There are two DP master systems and one IO subsystem: DP master system_1 is connected
via the DP interface of the CPU, and DP master system_2 is connected to the CPU via an
external DP master interface. The IO subsystem is connected via the integrated Ethernet
interface.
CPU 410-5H Process Automation/CPU 410 SMART
System Manual, 10/2013, A5E32631667-AA
T (IO subsystem) = T
P15
Note
If T (DP master system) < 0 or T
P15
Possible remedies are shown below the following example calculation. Make appropriate
changes and then restart the calculation at 1.
This time is referred to below as TP15_HW.
the minimum I/O retention time (T
T = 50 ms + min. I/O retention time [2]
P15_OD
Note
If T > T , stop the calculation here. Possible remedies are shown below the
P15_OD P15_HW
following example calculation. Make appropriate changes and then restart the calculation
at 1.
(Page 120), calculate the share of the maximum inhibit time for priority classes > 15 that
is required by the user program (T
Note
If T > T , stop the calculation here. Possible remedies are shown below the
P15_AWP P15_HW
following example calculation. Make appropriate changes and then restart the calculation
at 1.
obtained from:
T MAX (T , T
P15 = P15_AWP
P15
- (2 x T + T
PTO max_Akt WA
(IO subsystem) < 0, stop the calculation here.
P15
(DP master system) values.
P15
):
P15_OD
).
P15_AWP
) [3]
P15_OD
+ T + T + T
PROG PN_UM Device_UM
Link-up and update
8.3 Time monitoring
) [1]
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