Detailed Introduction:

The determination of the nature and attributes of traffic violations has significant temporal characteristics. In order to avoid disputes and conflicts in the law enforcement process, improve the seriousness and effectiveness of law enforcement penalties, the system uses the GPS timing master clock in the center to calibrate the devices in the system through the central platform, ensuring that the system has high timing accuracy and consistency in clock synchronization. When devices within the system restart, application software resumes operation, or network is disconnected and reconnected, clock calibration can be automatically performed.

The calibration cycle of the networked devices within the system shall not exceed 24 hours, and all front-end device points shall be synchronized with the monitoring center system clock at least once a day. The timing error within 24 hours shall not exceed 1.0s. The breakpoint resume function after network disconnection recovery uses an external GPS module to calibrate the server's time, and the forensic information is saved on the local hard drive to ensure accurate time.

Scheme description

The network front-end is equipped with an industrial switch MIE-5610-GP1, which includes one 100Mbps optical cable, six 10/100M electrical ports, and one GPS interface. The control host is connected to the switch through the network port, and the switch sends back to the central ME2U-16A/DC fiber optic transceiver aggregation transceiver through the optical port. The aggregation transceiver is connected to the core switch through a network cable to achieve communication.

Under normal network conditions, the NTP time obtained by the control host is the NTP server time (master). In the event of network abnormalities, the NTP time obtained by the control host is the local industrial switch; MIE-5610-GP1 receives GPS signals, obtains time information, and uses NTP protocol to time Ethernet devices.

Principle of NTP time switching between primary and backup: The local control host protocol can configure multiple NTP server addresses, and the system will automatically switch between primary and backup time servers according to the network connection. When configuring the local control host project, priority 1 is selected for the central NTP server time, and priority 2 is selected for the local industrial switch MIE-5610-GP1 timing.