Design and implementation of clock synchronization scheme for mine distributed acquisition system

Due to its accuracy and application limitations, single clock synchronization technology can not meet the high-precision and high-reliability clock synchronization accuracy requirements of the mine distributed acquisition system. In order to solve the above problems, a three-level coordinated clock synchronization scheme based on Beidou+IEEE 1588V2+local backup clock is proposed. The T600-BDGOCXC Beidou timing server is selected to be deployed on the ground as the master clock to provide absolute clock with nanosecond precision for the system. The STM32F407+DP83848 and PTPd protocol stack are used to implement the acquisition nodes that support IEEE 1588V2 protocol. The absolute clock of Beidou is synchronized to each acquisition node through the mine ring network. The local backup clock is implemented by using the STM32F407 internal RTC (Real-time Clock), which provides each acquisition node with time stamp initial value with second-level precision, so that each acquisition node can synchronize with the master clock in the shortest time. The test results show that the clock synchronization precision is 162 ns after 1 min when the Beidou timing server and the acquisition nodes are directly connected through the switch. The clock synchronization precision is 565 ns when the Beidou timing server and the acquisition nodes are connected through the three-level switch. When the Beidou timing server fails, the acquisition node with high priority is upgraded to be the master clock and provides timing for the remaining acquisition nodes with strong reliability.