Setting The Sampling Times - Siemens SINAMICS S120 Function Manual

7.2.4

Setting the sampling times

Terminology
The software functions installed in the system are executed cyclically at different sampling
times (p0115, p0799, p4099).
Safety functions are executed within the monitoring clock cycle (p9300/p9500) and TM54F is
executed within the sampling time (p10000).
Communication on PROFIBUS is handled cyclically by means of the communication clock
cycle.
During the PROFIsafe scan cycle, the PROFIsafe telegrams issued by the master are
evaluated.
Rules
● The monitoring clock cycle (p9300/p9500) can be set between 500 μs to 25 ms.
● Isochronous PROFIBUS
Safety Integrated
Function Manual, (FHS), 11/2009, 6SL3097-4AR00-0BP0
Note
The monitoring clock cycle must be the same on all drives.
However, the calculation time required for the Extended Functions in the Control Unit
depends on the monitoring clock cycle, that is, shorter clock cycles extend the calculation
time. The availability of a specific monitoring clock cycle therefore depends on calculation
time resources of the Control Unit.
Calculation time resources on the Control Unit are influenced primarily by the number of
drives, the number of drives with enabled Extended Functions, the connected DRIVE-
CLiQ components, the selected DRIVE-CLiQ topology, the use of a CBE20 and by the
selected technological functions.
– The monitoring cycle (p9300/p9500) must be an integer multiple of the actual value
update clock cycle. p9311/p9511 or when p9311/p9511 = 0, the isochronous
PROFIBUS communication clock cycle is used for actual value acquisition.
– The current controller cycle must be no more than a quarter of the length of the actual
value update clock cycle.
– The sampling time of the current controller (p0115[0]) must be at least 125 µs.
7.2 Commissioning Safety Integrated functions
Commissioning
127