Siemens SIMATIC S7-400H Manual page 124

Linking and Synchronizing
8. From Section 6.3.4 determine the share of the maximum blocking time for
priority classes > 15, which is dependent on the user program (T
Note
If T
P15_AWP
are listed after the following example calculation. Make the appropriate
modifications and start the calculation from 1 again.
9. The recommended value for the max. blocking time for priority classes > 15
now results from:
T MAX (T
P15 =
Example of the Calculation of T
In the following the maximum permissible period of time on update during which
the operating system performs no program scanning and no I/O updates is
determined for a given system configuration.
There are two DP master systems: DP master system_1 is "connected" to the
CPU via the MPI/DP interface of the CPU and DP master system_2 via an external
DP master interface module.
1. From the bus parameters in STEP 7:
T = 25 ms
TR_1
T = 30 ms
TR_2
T
DP_UM_1
T
DP_UM_2
2. From the Technical Data for the DP slaves used:
T
SLAVE_UM_1
T
SLAVE_UM_2
3. From the technological specifications for your system:
T
PTO_1
T
PTO_2
4. From the user program:
T = 300 ms
WA
T
PROG
6-22
> T the calculation is to be stopped here. Possible remedies
P15_HW
, T
P15_AWP P15_OD
P15
= 100 ms
= 80 ms
= 30 ms
= 50 ms
= 1250 ms
= 1200 ms
= 50 ms
)
Automation System S7-400H Fault-tolerant Systems
).
P15_AWP
[3]
A5E00068197-07