Siemens SINAMICS G120 Operating Instructions Manual page 190

Configuring the fieldbus
7.8 Communication over CANopen
The following diagram shows the principle of synchronous and asynchronous transmission:
Figure 7-22
For synchronous TPDOs, the transmission mode also identifies the transmission rate as a
factor of the SYNC object transmission intervals.
The CAN controller transfers data from synchronous RPDOs that it received after a SYNC
signal only after the next SYNC signal to the inverter.
Note
The SYNC signal synchronizes only the communication on the CANopen bus and not
functions in the inverter, e.g. the clock times of the speed control.
PDO services
The PDO services can be subdivided as follows:
● Write PDO
● Read PDO
● SYNC service
Write PDO
The "Write PDO" service is based on the "push" model. The PDO has exactly one producer.
There can be no consumer, one consumer, or multiple consumers.
Via Write PDO, the producer of the PDO sends the data of the mapped application object to
the individual consumer.
Read PDO
The "Read PDO" service is based on the "pull" model. The PDO has exactly one producer.
There can be one consumer or multiple consumers.
190
Principle of synchronous and asynchronous transmission
Converter with the CU250S-2 Control Unit (vector)
Operating Instructions, 06/2013, FW V4.6, A5E31759476B AB