A process device with diagnostics for use in an industrial process includes a process variable sensor or controller element which is configured to sense or control a process variable of a process fluid of the industrial process. Circuitry is coupled to the process variable sensor or control element and configured to measure or control a process variable of the industrial process. A wireless communication adapter includes wireless communication circuitry configured to communicate in the industrial process. The wireless communication circuitry is further configured to receive a process signal from another process device. Diagnostic circuitry is configured to diagnose operation of the industrial process as a function of the sensed process variable and the received process signal.