Siemens SINUMERIK 840D sl Function Manual page 219

05.08
S 0...m * IPO: This time component only becomes applicable if delays are in-
curred on the PLC side. In this case, in each subsequent IPO clock cycle, it is
determined as to whether the PLC is ready to communicate again.
S OB40_INT is the maximum permissible time to initiate the interrupt on the NCK
side up to execution of the PROFIsafe software and a ready signal to the NCK.
The time is mainly determined by the run time (propagation time) of the F driver
implementation on the PLC side and the PLC user program to be run–through
in the OB40 context. These times typically lie in the vicinity of a few millisec-
onds.
S The specified maximum times are theoretical values; it is extremely improbable
that they actually occur in practice.
Reason:
– It is improbable that the run time of the PLC–F driver is delayed – in the
OB40 context – by the maximum time of 50 ms. The reason for this is that
the interrupting organizational blocks (OB8x) only have such long run times
in extremely few cases.
– For the theoretical value, it would be necessary that two consecutive runs of
the PLC–PROFIsafe master driver in the OB40 context are delayed by the
permitted maximum of 50 ms – this is extremely improbable.
– The maximum time of 150 ms for the user program is not reached in any of
the applications relevant in practice.
PLC processing times
Time:: T(FDI–>DB18)
Formula
Max. times
Typical times
Time:: T(DB18–>FDO)
Formula
Max. times
Typical times
Time:: T(FDI–>FDO)
Formula
Max. times
Typical times
1) Typical times: PST = 16 ms; OB1 = 30 ms
© Siemens AG 2008 All Rights Reserved
SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) – 05.2008 Edition
2 * PST + 1 * OB1
2 * 50 ms + 1 * 150 ms
1)
2 * 16 ms + 1 * 30 ms
2 * PST + 1 * OB1
2 * 50 ms + 1 * 150 ms
1)
2 * 16 ms + 1 * 30 ms
4 * PST + 2 * OB1
4 * 50 ms + 2 * 150 ms
1)
4 * 16 ms + 2 * 30 ms
Connecting Sensors/Actuators
7.2 Connecting I/O via PROFIsafe
250 ms
62 ms
250 ms
62 ms
500 ms
124 ms
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