A field mountable dedicated process diagnostic device (100) is used for diagnosing operation of an industrial control or monitoring system. An input (102) is configured to receive at least one process signal (112A-N) related to operation of the industrial process. A memory (44) contains diagnostic program instructions configured to implement a diagnostic algorithm using the process signal. The diagnostic algorithm is specific to the industrial process. A microcontroller (42) performs the diagnostic program instructions and responsively diagnoses operation of the process based upon the process signal.
