Problem integrating Ladder Logic (LD) with Arduino_OPC_UA in Arduino PLC IDE

[limonAlfredo]

I’m working with the Arduino PLC IDE and trying to integrate Ladder Logic (LD) with the Arduino_OPC_UA library. The project compiles successfully and uploads to the device, but the PLC stops running as soon as I start the program. There are no logs or error messages; the only indication is that the PLC status LED turns red. After that, the program does not respond anymore.

What I’ve tried:

Confirmed the project compiles without errors.
Verified that OPC UA works correctly in a simple sketch (without Ladder Logic).
Verified that Ladder Logic works correctly by itself.
Tested on two different devices with the same result.

My question:
Is there something special that needs to be configured to make Arduino_OPC_UA work inside a Ladder Logic project?
Is there an example or recommended way to integrate OPC UA variables into LD?

Any help or guidance is very appreciated.
Thanks in advance.

I am using Arduino Opta AFX00002 and Arduino PLC IDE 1.0.8

[Chrismettal]

I'm facing the same behavior on an AFX00003 with PLC IDE 1.0.8.

• Simple ST PLC code runs fine
• The opc example uploaded via Arduino IDE 2 runs fine and can be connected to
• Combining the two in the PLC IDE code crashes the PLC (4 short, 4 long red LEDs)