The subject is to provide a technique of dealing with an internal state of a controller in an edge device by cooperation between an edge device and a computer such as a cloud server, and to generalize data communication for the cooperation and reduce an amount of data communication. Provided is a distributed system including an edge device and a diagnostic data computer. The edge device includes an in-edge controller including at least a processing unit, and a system element to be monitored by the in-edge controller. The processing unit diagnoses presence or absence of an abnormality in the processing unit due to an abnormality occurring in the system element, generates first diagnostic data indicating presence or absence of the abnormality of the processing unit, converts the first diagnostic data into second diagnostic data indicating a type of the abnormality of the processing unit, and transmits the second diagnostic data to the diagnostic data computer.