Siemens Industry Online Support
Siemens AG
Entry type: Application example Entry ID: 40556214, Entry date: 07/30/2013

Data Synchronization with S7 Communication between several S7-1200 Substations and one S7-1500/300 Head PLC

  • Entry
  • Associated product(s)

A cyclic communication is often required for synchronization tasks and exchanging control and status information between a head-end station (here client) and several distributed substations (here server) via Industrial Ethernet.
The following points shall be realized:

  • Supplying all field controllers with the same or differend data records from the head-end station.
  • Updating the data records from all substations in the head-end station.

In an application example, the solution provides a modular STEP 7 V 12 program for the synchronization between head-end and substations. The employed hardware components are S7-1200 CPUs in the substations, and an S7-1500 or alternatively an S7-300 CPU in the head-end station. The program offers the following functionalities:

  • Supplying the substations (servers) with data records defined by the user (write synchronization).
  • Updating defined data records from the substations (servers) with the client head-end station (client) (read synchronization).
  • Optional clock synchronization from the head-end station (client) to the servers.

The solution introduced here offers you the following advantages:

  • Simple changes of size and storage location of the data areas to be synchronized in the example project..
  • Scalable project for application of less or more than four substations.
  • Modular program setup. Both synchronization directions are encapsulated completely in function blocks and can be used separately in your applications.
  • In the example program, some measurements for the transfer time were generated which help you estimate your synchronization time.


Content of Downloads


Consistent Data Synchronization with S7 Communication between several Substations and one Head-end Station
40556214_S7-Komm_Sync_DOKU_V2_0_en.pdf ( 2773 KB )
STEP 7 project (SIMATIC STEP 7 V12)
40556214_S7-Comm_Sync_CODE_v2_0.zip ( 2792 KB )

Further Information



High-performance data synchronization between multiple S7-1200-based field devices and an S7-1200 or a PC-based head PLC via flexibly configurable communication (Set 17) Entry ID:

Security Notice

The functions and solutions described in this article confine themselves to the realization of the automation task predominantly. Please also take into account that corresponding protective measures have to be taken in the context of Industrial Security when connecting your equipment to other parts of the plant, the enterprise network or the Internet. Further information can be found under the Entry ID 50203404.

Last Changes
Cancellation of the task with open communication and T blocks.

more flexlible design of the program with S7 communication: selectable synchronization areas.

Additional Keywords
Central station, field station, data concentratorsynchronization

Security information
In order to protect technical infrastructures, systems, machines and networks against cyber threats, it is necessary to implement – and continuously maintain – a holistic, state-of-the-art IT security concept. Siemens’ products and solutions constitute one element of such a concept. For more information about cyber security, please visit