Siemens SIMATIC S7-400 Manual page 78

PROFIBUS DP
5.1 CPU 41x-3 PN/DP as DP master / DP slave
Modes for DPV1 components
● S7-compatible mode
● DPV1 mode
DPV1 and EN 50170 compatibility
You can continue to use all existing slaves after the system conversion to DPV1. These do
not, however, support the enhanced function of DPV1.
DPV1 slaves can be used in systems that are not converted to DPV1. In this case, their
behavior corresponds with that of conventional slaves. SIEMENS DPV1 slaves can be
operated in S7-compatible mode. For the DPV1 slaves of other manufacturers, you need a
GSD file < Rev. 3 file to EN 50170.
Further Information
Information on the migration from EN 50170 to DPV1 is available on the Internet, on the FAQ
pages "Changing from EN 50170 to DPV1", FAQ ID 7027576, of the Customer Support.
http://www.siemens.com/automation/service&support
Monitor/Modify, Programming via PROFIBUS
As an alternative to the MPI interface, you can use the PROFIBUS DP interface to program
the CPU or execute the programming device functions Monitor and Modify.
Note
The execution of programming and monitor/modify functions via PROFIBUS DP interface
prolongs the DP cycle.
Constant bus cycle time
This is a property of PROFIBUS DP. The "Constant bus cycle time" function ensures that the
DP master always starts the DP bus cycle within a constant interval. From the perspective of
the slaves, this means that they receive their data from the master at constant time intervals.
In STEP 7 V 5.2 or higher, you can configure constant bus cycle times for PROFIBUS
subnets.
5-4
In this mode, the components are compatible with EN 50170. Note that you cannot utilize
the full DPV1 functionality in this mode.
In this mode, you can utilize the full DPV1 functionality. Automation components in the
station that do not support DPV1 can be used as before.
S7-400 Automation System, CPU Specifications
Manual, 10/2006, 6ES7498-8AA04-8BA0