Direct Data Exchange - Siemens sinamics dcp Operating Instructions Manual

Operation
8.5 Communication via PROFIBUS DP
8.5.4

Direct data exchange

8.5.4.1 Direct data exchange
For PROFIBUS DP, the master interrogates all of the slaves one after the other in a DP
cycle. In this case, the master transfers its output data (setpoints) to the particular slave and
receives as response the input data (actual values). Fast, distributed data transfer between
drives (slaves) is possible using the "direct data exchange" function without direct
involvement of the device.
The following terms are used for the function described in this chapter:
● Slave-to-slave communication
● Data exchange broadcast (DXB.req)
● Direct data exchange (is used in the following)
Image 8-24
Publisher
With the "direct data exchange" function, at least one slave must act as the publisher.
The publisher is addressed by the master when the output data is transferred with a modified
layer-2 function code (DXB.req). The publisher then sends its input data for the master with a
broadcast telegram to all bus nodes.
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Direct data exchange communication with the publisher-subscriber model
Operating Instructions, 05/2016, A5E34382853K
SINAMICS DCP