Functions
8.1 PROFIBUS DP
ET 200pro distributed I/O system
Operating Instructions, 03/2013, A5E00335544-08
181
8.1.2
Direct data exchange
Properties
The ET 200pro can be used as transmitter (publisher) for direct data exchange (slave-to-
slave communication).
Requirements
The DP master used must support direct data exchange. For further information, refer to the
description of the DP master.
Operating principle
Direct data exchange (slave-to-slave communication) is characterized by PROFIBUS DP
nodes that "listen in" on the bus and know which data a DP slave returns to its DP master.
This mechanism allows the "listening node" (recipient/subscriber) direct access to deltas of
input data of remote DP slaves.
In your STEP 7 configuration, define the address area of the recipient in which the required
data of the publisher will be placed, based on the peripheral input addresses.
Example
The diagram below illustrates direct data exchange "relationships" that you can configure
with an ET 200pro as publisher and which nodes can "listen in" as potential recipients.
Figure 8-3
Example of data exchange
