Why do some old Quantum I/O modules randomly go to fallback mode when communicating with 140CRA31200 (Ethernet) drop head

This is due to the fact that old components used in IO manufactured before 2008 are more stringent in regards to the internal timing specifications with CRA.

As we could not redesign the "old" IO modules that exist in the field already, the correction is applied in the 140CRA31xxxx .

This correction is embedded in PV06 or later versions of 140CRA31xxxxx