Siemens SIMATIC CPU 410 System Manual page 126

Link-up and update
8.3 Time monitoring
1. Based on the bus parameters in STEP 7, determine the following for each DP master
system:
– T
– DP changeover time (referred to below as T
2. From the STEP 7 configuration, determine the following for each IO subsystem:
– Maximum update time of the IO subsystem (referred to below as T
– PN changeover time (referred to below as T
3. Based on the technical data of the switched DP slaves, determine the following for each
DP master system:
– The maximum changeover time of the active communication channel
4. Based on the technical specifications of the switched PN devices, determine the following
for each IO subsystem:
– Maximum changeover time of the active communication channel (referred to below as
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.
126
for the DP master system
TR
(referred to below as T
T ).
Device_UM
(referred to below as T
(DP master system) = T
P15
(IO subsystem) = T
P15 PTO
(DP master system) < 0 or T
P15
DP_UM
PN_UM
).
SLAVE_UM
).
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
)
max_Akt
)
)
PROG
+ T + T
PROG DP_UM SLAVE_UM
+ T + T
PROG PN_UM Device_UM
CPU 410 Process Automation/CPU 410 SMART
System Manual, 05/2017, A5E31622160-AC
)
)
WA
) [1]
) [1]