PFC 750-8112 Communication Issue with Weintek cMT2108X2 HMI

CODESYS
1

I’m experiencing a communication issue between a WAGO 750-8112 (Firmware 28) PLC and a Weintek cMT2108X2 HMI.

Configuration

  • Created and updated the latest Symbol Configuration in the PLC project.
  • Downloaded the project to the PLC.
  • Imported PLC tags into EasyBuilder Pro from the Symbol Configuration file.
  • Selected WAGO TCP/IP as the communication driver.
  • PLC IP address configured correctly.
  • Port: 11740
  • Username: admin
  • Password: wago

Issue

The HMI continuously shows “Device No Response”.

Interestingly, if I link a BOOL variable to a toggle button on the HMI, I can successfully write to the PLC and the bit changes state as expected.

However:

  • The HMI still reports “Device No Response”.
  • PLC variables cannot be read or displayed on the HMI.
  • Numeric values remain unavailable.
  • Communication appears to work for writing but not for reading.

Since writing to PLC variables works, I suspect the connection is only partially established or there may be a read-access/configuration issue.

Any suggestions or experience with this setup would be greatly appreciated.

2

What protocol is it ?
Can you use Wireshark to read those frames ?
You should be able to use the PLC mirroring capability to read all frames:

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3

We are using Ethernet communication. We have already tested the same setup using a Weintek HMI with a WAGO PFC 750-8212 PLC, and it worked correctly with the same communication settings. That’s why we believe the network configuration is correct and are trying to understand why it is not working in this case.

4

Device No Response can be misleading. Any variables anywhere that you have mapped that no longer exist in the symbol config can trigger that message. Vars inside plain buttons usually will flag the compiler, but vars hidden in expressions or data transfer can be missed by it. It sounds like your communication is good.

Weintek support has CODESYS experience and is quite helpful and responsive on their message board as well.