The tower clock is divided into indoor and outdoor parts from the appearance, in which there is a master clock control system indoors. Outdoor is the sub clock part, which can be divided into movement, clock needle, scale, lighting system and time reporting speaker. The outdoor clock controller has its own clock circuit to generate signals with an accuracy of 2 seconds / month. At the same time, the CPU continuously receives the time signals from GPS and Beidou signal and corrects its own time signals, so as to ensure the accuracy of its time signals. The master clock continuously sends the time signal to the slave clock, and outputs the driving signal to drive the motor to complete the running time. The slave clock returns its state to the master clock and receives the monitoring of the master clock. At the same time, the travel time of the slave clock is also monitored by the feedback switch, so as to ensure that the whole slave clock forms a closed-loop system. The master clock and slave clock form a large closed-loop system. Therefore, the accuracy of the whole building clock system is guaranteed.
