Provided is a highly convenient communication device capable of detecting a communication error caused by an abnormality of a state of communication. A communication device capable of mutually communicating with an electrical device includes: a superimposed signal receiving unit that periodically receives a data signal related to the electrical device as a signal superimposed on an operation signal; a period determination unit that determines whether or not a communication error of the data signal detected by the superimposed signal receiving unit is able to be regarded as having occurred in a transition period of a value of the operation signal; and a state determination unit that determines a state of communication with the electrical device in accordance with the determination by the period determination unit.

An IO-Link master includes: an IO-Link communication port that communicates with an IO-Link device according to a predetermined communication protocol; a digital input port that receives a first signal value output from the IO-Link device; and a determiner that determines whether abnormality is generated in a digital input line connecting the digital input port to the IO-Link device based on a second signal value received with the IO-Link communication port and the first signal value.

A control system includes a controller for controlling a control target and redundant devices accessible from the controller. The control system includes a feature quantity generation unit that generates a feature quantity from data associated with the redundant devices, an abnormality detection unit that determines whether an abnormality has occurred in one of the redundant devices based on the feature quantity generated by the feature quantity generation unit and a predetermined abnormality detection parameter, a switch unit that switches the redundant devices between a working mode and a standby mode when the abnormality detection unit determines that an abnormality has occurred, and a learning unit that performs machine learning using the data associated with the redundant devices to determine the abnormality detection parameter.

An information processing apparatus includes a communication unit capable of communicating with mobile communication terminals, a detection unit that detects an event indicating a phenomenon that has occurred in a production apparatus, a first determination unit that determines mobile communication terminals associated with the event to be notified, as notification destination candidates for every type of event, mobile communication terminals to be notification destinations, an acquisition unit that acquires the current position of each mobile communication terminal that is a notification destination candidate, a calculation unit that calculates a time period for each mobile communication terminal that is a notification destination candidate to reach the production apparatus, and a second determination unit that determines a mobile communication terminal whose calculated first time period is relatively short, as a notification destination of the event to be notified, from among the mobile communication terminals that are the notification destination candidates.