How can you link an S7-300 module as DP slave to a DP/PA-Link
in the hardware configuration of STEP 7?
The normal way of linking the above-mentioned modules from the
PROFIBUS-DP catalog of the hardware configuration of STEP 7 to the
DP master segment of the DP/PA-Link is not possible. Linking the
S7-300 as slave to a DP/PA-Link is only possible via the GSD files.
When handling CPU-I slaves via GSD file you must make sure as user
that the I/O areas match each other. First download the GSD
files required for the above-mentioned modules onto your STEP 7
system. If these GSD files are already incorporated in your
hardware configuration, you can skip this step. The GSD files are
available in the Internet in the Entry ID: 113652 "PROFIBUS GSD
files : SIMATIC". Via the menu item "Options > Install
New GSD…" you can incorporate the GSD files in your hardware
configuration. Please close your S7 station before doing
Fig. 1: Installation of the new GSD file of the catalog
Open your hardware configuration again and configure the module
IM157 (e.g. the DP/PA-Link with MLFB: 6ES7157-0AA81-0XA0). From the
PROFIBUS DP catalog/subdirectory "DP/PA link" you can link this
module directly to the segment of the redundant master system using
Fig. 2: Selecting the DP/PA link in the HW Config
Specify a PROFIBUS address for the DP/PA-Link and select
"Interface Module for PROFIBUS-DP" (see Fig. 3).
Fig. 3: Selecting the interface module in the HW Config
You will then find the S7-300 modules in the PROFIBUS DP catalog
under "Additional Field Devices" (see Fig. 4).
Fig. 4: Selecting the S7-300 module
Now use drag-and-drop to copy these modules to the master
system. Make sure here that you select the right bus system (in
Fig. 5: PROFIBUS (5)) and a PROFIBUS address. If you use the
GSD files available at the time, then the CPU 315-2 DP is
incorporated as DPV0 slave.
Fig. 5: Configuration in the HW Configuration
Now you still have to create the HW configuration for the CPU
being operated as DP slave. In the case of a standard slave, you
usually only have to set the DP address and the baud rate.
Create an S7-300 station according to your HW
Connect the DP interface to a bus. (You now have to select a bus
other than the one on your DP/DP link, because you have already
assigned the address for the DP slave here).
Set the DP interface of the CPU to slave mode (double-click DP
Interface > Operating Mode tab). Please make sure that the PG
functions are not activated.
Fig. 6: Settings as DP slave
Set the bus parameters for the bus. Use the same bus parameters
as you have set on the secondary side of your DP/DP link.
Load the configuration into the DP slave CPU.
Interface modules, I/O devices