Hi, I have the same problem with an OPLC V120, an Expansion Adapter EX-A2X and a IO-DI8-TO8.
First, I had an Expansion Adapter EX-A1: the OPLC did'nt show the error message but the led RUN in the IO module was flashing...
Then, I put the EX-A2X: Early, the communication is established but in a few minutes the OPLC show the error message and the comunnication is broken...
I did test without the IO connections but the problem persists.
Thank you for your help...