Siemens SIMATIC PCS 7 CPU 410-5H System Manual page 130

Link-up and update
8.3 Time monitoring
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.
1. Based on the bus parameters in STEP 7:
T
T
T
T
2. Based on the configuration in STEP 7:
T
T
3. Based on the technical data of the DP slaves used:
T
T
4. Based on the technical specifications of the PN devices used:
T
5. Based on the technological settings of your system:
T
T
T
6. Based on the user program:
T
T
7. Based on the formula [1]:
= 1250 ms - (2 x 25 ms + 300 ms + 50 ms + 100 ms + 30 ms) = 720 ms
= 1200 ms - (2 x 30 ms + 300 ms + 50 ms + 80 ms + 50 ms) = 660 ms
130
P15
= 25 ms
TR_1
= 30 ms
TR_2
= 100 ms
DP_UM_1
= 80 ms
DP_UM_2
= 8 ms
max_Akt
= 110 ms
PN_UM
= 30 ms
SLAVE_UM_1
= 50 ms
SLAVE_UM_2
= 20 ms
Device_UM
= 1250 ms
PTO_1
= 1200 ms
PTO_2
= 1000 ms
PTO_PN
= 300 ms
WA
= 50 ms
PROG
T (DP master system_1)
P15
T (DP master system_2)
P15
CPU 410-5H Process Automation
System Manual, 09/2014, A5E31622160-AB