A method of diagnosing a distributed operational system having a field device, a field processing module coupled to the field device, a bitbus, a fieldbus, and an auxiliary processing module communicating with the bitbus and the fieldbus. The method includes generating a field operating characteristic at the field device, processing the field operating characteristic at the field processing module, and generating field operating data including a field diagnostic parameter as a function of the field operating characteristic. The method also includes communicating the field operating data including the field diagnostic parameter over the bitbus from the field processing module to the auxiliary processing module. The method further includes generating at the auxiliary processing module auxiliary field data as a function of the received field operating data and communicating the auxiliary field data over the fieldbus.