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

Dear HMS 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/ MPI/PPI Multimaster extension 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 ?

Let me know if you need additional information.

Thanks in advance for your help.

Best regards,


The Flexy can’t support having the other master. As a workaround you could use the Ethernet port on the Weitek HMI to poll the PLC using the transparent ISOTCP<=> PPI Feature. In the Flexy S7-200 IO Server set as the destination node the PPI of the PLC and in the weitek use the IP of the Flexy.