This access is possible with the 31x-2 DP CPUs that can be operated as I slaves. For this you parameterize the 31x-2 DP CPU as an intelligent DP slave and connect it to the PROFIBUS DP. You do this in the Properties of the DP interface.
Fig. 01: Changing the parameters of the DP interface
You then select the "Configuration" tab and configure the I/O configuration for the DP communication.
Examples of how to configure and parameterize a master-slave connection in STEP 7 between two S7 controllers are available in the entries below.
- Entry ID: 6518822, if both stations are in the same STEP 7 project.
- Entry ID: 19449428, if both stations are in separate STEP 7 projects.
A sample application for S7 basic communication with I_PUT and I_GET is available in Entry ID: 20987910.
The S7 CPU configured as I slave does not necessarily have to be active. It can also be configured as passive node, i.e. the Test, Commissioning, Routing parameter can likewise remain disabled.
When programming, note that you must specify a logical address (diagnostics address or I/O address) for the IOID B#16#54 parameter and for LADDR when calling SFC 72/73.