Siemens Industry Online Support
Siemens AG
Entry type: Application example Entry ID: 40556214, Entry date: 09/13/2019

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

  • Entry
  • Associated product(s)
This application example handles the data exchange via S7 communication between a S7-1500 or S7-300 as head PLC (client) and several S7-1200 substations (servers).

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 (TIA Portal) 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.

Version 2.1 for STEP 7 (TIA Portal) V15.1 or higher
  Documentation "Consistent Data Synchronization with S7 Communication between several Substations and one Head PLC" (1,6 MB)
 Registrierung notwendig  Sample project with one head PLC (S7-1500 or S7-300) and four substations (S7-1200) (1,1 MB)

Further Information
Application example "Data synchronization over open communication between multiple field devices (S7-1200) and a head PLC (S7-1200/ S7-300/ WinAC)"

Last Changes
Error elimination + update to TIA Portal V15.1

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
Rate entry
no rating
Requests and feedback
What do you want to do?
Note: The feedback always relates to the current entry / product. Your message will be forwarded to our technical editors working in the Online Support. In a few days, you will receive a response if your feedback requires one. If we have no further questions, you will not hear from us.