Abstract: There is provided a wireless communication system for transmitting periodic data from a first device to a plurality of second devices by wireless communication comprising: a first wireless device connected to the first device; and a plurality of second wireless devices connected to the plurality of second devices, respectively, wherein the first wireless device includes a first wireless portion and a first control portion, the second wireless device includes a second wireless portion and a second control portion, and the first control portion and the second control portion synchronize the first wireless device and the plurality of second wireless devices when a time until the first wireless device receives a response from the second wireless device after the first wireless device has transmitted the periodic data from the first device is equal to or less than a set value.

Abstract: An abnormality detection method according to one aspect of the present disclosure is a method of detecting an abnormality in an AC signal to be input from an AC power supply. The method includes, where an ideal AC signal is represented as V0 sin ?t (V0: amplitude, co: angular frequency, t: time), calculating an arithmetic value including a value represented by sin2?t+cos2?t and determining that the AC signal is abnormal when the arithmetic value is out of a threshold range.

Abstract: An abnormality detection method according to one aspect of the present disclosure is a method of detecting an abnormality in an AC signal to be input from an AC power supply. The method includes, where an ideal AC signal is represented as V0 sin ?t (V0: amplitude, co: angular frequency, t: time), calculating an arithmetic value including a value represented by sin2?t+cos2?t and determining that the AC signal is abnormal when the arithmetic value is out of a threshold range.