Siemens SIMOTION Function Manual page 32

Synchronizing SIMOTION devices with a higher-level bus cycle clock
3.2 Synchronizing a SIMOTION device without an isochronous DP master interface
Synchronization sequence
As soon as a higher-level bus cycle clock is available at the corresponding interface (DP slave
in PROFIBUS DP, sync slave in PROFINET IO) of the SIMOTION_2 device, the interface
automatically synchronizes itself with the defined bus cycle clock.
Note
Only a single cycle clock source is permitted on a SIMOTION device. For this reason:
If a SIMOTION device contains a PROFINET IO interface, a PROFIBUS DP interface can
no longer be operated as an isochronous DP slave.
After successful synchronization, the device cycle clocks (e.g. Servo, IPO, IPO2) and the
programs running in the SynchronousTasks are both synchronized with the received bus cycle
clock.
Should the bus cycle clock fail, a replacement cycle clock will be generated with the same
cycle time.
The current synchronization state is shown in the stateOfDpSlaveSynchronization system
variable. You can, for example, evaluate the synchronization state in the user program so that
in the event of a synchronization failure, execution of program sections that assume
synchronization would be prevented.
In addition, you can activate the alarms for initiating the PeripheralFaultTask. To do this, call
up the _enableDpInterfaceSynchronizationMode system function using the parameter
dpInterfaceSyncMode = SLAVE_ALARMMESSAGES_1:
● The _SC_DP_SLAVE_SYNCHRONIZED ( = 209) and
● The modeOfDpInterfaceSynchronization system variable is set to
See also the status diagram in the figure below.
The syntax of this system function is described in detail in the "System Functions/Variables
Devices" List Manual (reference list) and in the online help (see index).
Note
If the alarms for initiating the PeripheralFaultTask are activated, they must be activated in the
execution system and an appropriate program assigned. Otherwise the SIMOTION device
enters the STOP operating mode when this event occurs.
32
_SC_DP_SLAVE_NOT_SYNCHRONIZED ( = 210) events then initiate the
PeripheralFaultTask and can be queried in their TaskStartInfo (TSI#InterruptId).
SLAVE_ALARMMESSAGES_1.
Basic Functions for Modular Machines
Function Manual, 04/2014