Can't connect Flexy 205 to HMI & PLC with PPI MultiMaster

Dear support team,

I am facing technical issues while inter-connecting the following items by using PPI MuliMaster protocol :

  • 1 x HMI WeIntek MT8071ie (Master)
  • 1 x PLC Siemens S7200 SMART (Slave)
  • 1 x Modem EWON Flexy 205 w/ PPI Multimaster I/O card (Master)

As per my observation, the Flexy and the HMI are not able to communicate at the same time with the PLC :

  • When the HMI is communicating with the PLC, the Flexy stop receiving any data.
  • When the Flexy is communicating with the PLC, the HMI stop receiving any data.

If I connect only one of the item above to the PLC, everything is working fine.

The Flexy and HMI are inter-connected to the DB9 port of the PLC as follow :

Would you have any suggestion to solve this issue ?

Thanks in advance for your help.

Best regards,


This is most likely because the Flexy needs to be the only master and can’t support the multi-master. A colleague suggested a workaround:

[8:46 AM] Jean-Yves Fondu
The PLC muts be set as master also I think. Or I have a possible work arroud here, as the Weitek HMI has an ethernet port use it to poll the PLC using transparent ISOTCP<=> PPI Feature. In the S200IOserver set as destination node the PPI of the PLC and in the weitek use the IP of the Flexy