TIME SYNCHRONIZATION OF CONTROLLER

A controller includes: a master clock; a controller clock; a master clock management unit configured to synchronize the master clock with an external global clock and set a master time based on the master clock; a controller clock management unit configured to synchronize the controller clock with the master clock and perform time synchronization to synchronize a controller time based on the controller clock with the master time, and to transmit controller time data indicating the synchronized controller time to at least one local device; a window setting unit configured to set a plurality of time windows corresponding to a plurality of clock cycles of a clock signal for the time synchronization; a determination unit configured to determine whether one clock cycle of the plurality of clock cycles has started within one time window of the plurality of time windows, the one time window corresponding to the one clock cycle; and an update control unit configured to suspend the time synchronization corresponding to the one clock cycle, in response to determining that the one clock cycle has not started within the one time window.