Siemens SIMOTION Function Manual page 39

Behavior in the STOP operating mode
If the interfaces of a SIMOTION device are not consecutively synchronized, the input cycle
clock is monitored and a signal generated that leads to the _SC_DP_CLOCK_DETECTED
event in the RUN operating mode.
If the interfaces are consecutively synchronized, the synchronicity and the input cycle clock
are monitored. If the input cycle clock fails, a signal will be generated that results in the
_SC_DP_SYNCHRONIZATION_LOST event in the RUN operating mode.
The state of the DP slaves does not change. An activated slave remains activated and a
deactivated slave remains deactivated.
Behavior during the transition from STOP operating mode to RUN operating mode
The system variables are updated.
Processing of the user program will be delayed until (for example) any internal processing of
the system functions _activateDpSlave, _deactivateDpSlave, or _getStateOfDpSlave (see
Activating and deactivating nodes on the PROFIBUS or PROFINET IO (Page 57)) which is
still running has been completed. There is no separate time monitoring.
Behavior in the RUN operating mode
In the RUN operating mode, the events result in the PeripheralFaultTask being started with
the associated TSI#InterruptId. System functions can be called up in the user program or in
the PeripheralFaultTask.
The user can use the stateOfDpInterfaceSynchronization system variable and the
_getStateOfDpSlave system function to determine the current system state and restart its
application.
Behavior during the transition from RUN operating mode to STOP operating mode
The transition can be made at any time. It is possible that slaves may have been started already
or even deactivated. Interfaces can be synchronous or asynchronous.
All called system functions end in a defined state:
● The _synchronizeDpInterfaces system function will be cancelled.
● The system functions _activateDpSlave, _deactivateDpSlave, and _getStateOfDpSlave will
Basic Functions for Modular Machines
Function Manual, 04/2014
Synchronizing SIMOTION devices with a higher-level bus cycle clock
undergo further internal processing.
3.4 Behavior in the STOP and RUN operating modes
39