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Author's profile photo Dominik Tylczynski

Channel synchronization in open source PLC emulator


As per SAP Help on Telegram Repetition and Channel Check

Synchronization means that after a connection was established by SAP EWM, the programmable logic controller (PLC) was given the opportunity to send all messages that accumulated during the period of disconnection.

PLC Sim emulator does not send telegrams if SAP EWM MFS communication channel is not started and not connected to the simulator. In fact the SEND button is disabled unless SAP EWM MFS is connected


Therefore it is recommended to switch off the channel synchronization while working with the emulator. That can be set up in SPRO SCM Extended Warehouse Management -> Extended Warehouse Management -> Material Flow System (MFS) -> Master Data -> Define Communication Channel

Nevertheless it is perfectly possible to simulate and test synchronization scenarios with the emulator.

Channel synchronization with the PLC emulator

The synchronization process is implemented with 3 types of telegrams:

  • synchronization setup, SYES
  • synchronization start, SYBE
  • synchronization end, SYED

The demo uses the following styling of the telegrams

  • LIFE – red
  • SYES – orange
  • SYBE – yellow
  • SYED – blue
  • handshake request – bold font
  • handshake acknowledgment – italic font

That is set up with the following properties in the emulator configuration file:


First, I have activated the synchronization for the LMS1 CONSYS 1 communication channel. The channel is stopped


Now, the channel is started from /SCWM/MON, node Material Flow System -> Communication Channel. The channel status is set to A indicating synchronization being executed. That sends the SYES telegram from SAP EWM MFS


Next, the SYBE telegram is sent to SAP EWM MFS indicating the beginning of the synchronization


The communication channel status is not changed by the SYBE telegram, as it is only the beginning of the synchronization. The synchronization is concluded with the SYEN telegram sent to SAP EWM MFS


The SYEN telegram updates the status of the communication channel to B, indicating successful synchronization


Now the channel is connected and synchronized. The LIFE telegrams start flowing and the channel is ready for regular communication


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      Author's profile photo Rafał Wawrzyniak
      Rafał Wawrzyniak

      Hi Dominik - great job regarding the PLC Emulator.

      I apologise , if this question will be trivial, I am newbie  - just only 3 years in SAP enviroment as a keyuser.

      Is there any EWM emulator as well, you know to test on test enviroment, without the real system?

      I'm only using SAP PM on my daily job - but your project interested me , especially from the PLC and SAP as well..




      Author's profile photo Dominik Tylczynski
      Dominik Tylczynski
      Blog Post Author

      Hello Rafał Wawrzyniak

      There is no such a thing as SAP EWM emulator. EWM is a large SAP module / product to manage warehouse processes. There is no way to simulate it. You are working with SAP PM, so you know there is no PM emulator. It is exactly the same way with EWM.

      Author's profile photo Rafał Wawrzyniak
      Rafał Wawrzyniak



      Anyway , thx for the reply..I count for something cause I don't know nothing about EWM , but this is intteresting story with the emulation.