Efficient Networks Siemens Sinamics S120 - Manual (Page 450)

Communication PROFIBUS DP/PROFINET IO
10.3 Communications via PROFINET IO
Drive Functions
450
Function Manual, (FH1), 07/2007 Edition, 6SL3097-2AB00-0BP4
Setting criteria for times
● Cycle (T
DC
)
– T
DC
must be set to the same value for all bus nodes. T
DC
is a multiple of SendClock.
– T
DC
> T
CA_Valid
and T
DC
≧ T
IO_Output
T
DC
is thus large enough to enable communication with all bus nodes.
NOTICE
After T
DC
has been changed on the PROFINET IO controller, the drive system must
be switched on (POWER ON) or the parameter p0972=1 (Reset drive unit) must be
set.
● T
IO_Input
and T
IO_Output
– Setting the times in T
IO_Input
and T
IO_Output
to be as short as possible reduces the dead
time in the position control loop.
– T
IO_Output
> T
CA_Valid
+ T
IO_Output_MIN
● Settings and optimization can be done via a tool (e.g. HW Config in SIMATIC S7).
User data integrity
User data integrity is verified in both transfer directions (IO controller <––> IO device) by a
sign of life (4-bit counter).
The sign-of-life counters are incremented from 1 to 15 and then start again at 1.
● IO controller sign of life
– STW2.12 ... STW2.15 are used for the IO controller sign of life.
– The IO controller sign-of-life counter is incremented on each IO controller application
cycle (T
CACF
).
– The number of sign-of-life errors tolerated can be set via p0925.
– p0925 = 65535 deactivates sign-of-life monitoring on the IO device.
– Monitoring
The IO controller sign-of-life is monitored on the IO device and any sign-of-life errors
are evaluated accordingly.
The maximum number of tolerated IO controller sign-of-life errors with no history can
be set via p0925.
If the number of tolerated sign-of-life errors set in p0925 is exceeded, the response is
as follows:
1. A corresponding message is output.
2. The value zero is output as the IO device sign of life.
3. A new synchronization with the IO controller sign of life is started.
● IO device sign of life
– STW2.12 ... STW2.15 are used as IO device sign of life.
– The IO device sign-of-life counter is incremented in each DC cycle (T
DC
).