CN210536790U

CN210536790U - Shore bridge CCTV time service system

Info

Publication number: CN210536790U
Application number: CN201922108337.5U
Authority: CN
Inventors: 沈贵贤; 黄之成; 赵悦
Original assignee: Yichang Fanhaijutao Technology Co ltd
Current assignee: Yichang Fanhaijutao Technology Co ltd
Priority date: 2019-11-29
Filing date: 2019-11-29
Publication date: 2020-05-15
Anticipated expiration: 2029-11-29

Abstract

A CCTV time service system for a shore bridge comprises a UBLOX module, a main control module and a CPLD logic unit; the UBLOX module is electrically connected with the main control module, the main control module is electrically connected with the CPLD logic unit, and the CPLD logic unit is electrically connected with the temperature compensation crystal oscillator; the UBLOX module is used for acquiring time information by using a GPS signal and then sending the time information to the main control module; the main control module is electrically connected with the CPLD logic unit and is used for realizing liquid crystal display and simultaneously sending the time information to the hard disk video recorder of the CCTV system through a network port or a 485 interface. The system can acquire time information from a satellite, synchronizes the time of the video equipment with the time of Beijing, and has strong time synchronization stability and small error.

Description

Shore bridge CCTV time service system

Technical Field

The utility model belongs to the technical field of video equipment is automatic to the time, in particular to bank bridge CCTV time service system.

Background

At present, video equipment is added and used in port equipment as production assistance, working efficiency is improved, safety accidents are reduced, along with more and more video equipment accesses, the video equipment needs to be managed uniformly and effectively, accurate time is needed to serve as a base line, so that the video management has reference value, the current video equipment updates time through a crystal oscillator, errors can reach 5 minutes every month, half a year later, time information basically does not have reference value, and therefore time synchronization updating needs to be carried out by one piece of equipment.

Disclosure of Invention

In view of the technical problem that the background art exists, the utility model provides a bank bridge CCTV time service system can obtain time information from the satellite above, with video equipment's time and Beijing time synchronization, and to the time stability strong, the error is little.

In order to solve the technical problem, the utility model discloses following technical scheme has been taken and has been realized:

a CCTV time service system for a shore bridge comprises a UBLOX module, a main control module and a CPLD logic unit; the UBLOX module is electrically connected with the main control module, the main control module is electrically connected with the CPLD logic unit, and the CPLD logic unit is electrically connected with the temperature compensation crystal oscillator;

the UBLOX module is used for acquiring time information by using a GPS signal and then sending the time information to the main control module; the main control module is electrically connected with the CPLD logic unit and is used for realizing liquid crystal display and simultaneously sending the time information to the hard disk video recorder of the CCTV system through a network port or a 485 interface.

In a preferred scheme, the frequency of the temperature compensation crystal oscillator is 50MHz, and the temperature compensation crystal oscillator is used for improving the time service precision.

In a preferred scheme, the main control module is an STM32 main control chip.

In a preferred scheme, the size of the memory of the STM32 master control chip is 64 Kb.

This patent can reach following beneficial effect:

the time information is acquired by a GPS signal through a UBLOX module, then the information is sent to an STM32 main control chip and a CPLD logic unit for processing to realize liquid crystal display, and meanwhile, the time information is sent to a hard disk video recorder of a CCTV system through a network port or a 485 interface, so that the time of the hard disk video recorder is accurate, the video is convenient to call later, and the temperature compensation crystal oscillator can enable an internal clock to be more stable and improve the time service precision. The time synchronization server realizes time service on the network video equipment, the time service duration is not limited, and the equipment can be conveniently accessed to a video system at any time. The CCTV system supports the time synchronization of the local area network, so that the hard disk video recorder and the camera are synchronized with the time of Beijing, and the synchronization error is small.

Drawings

The invention will be further explained with reference to the following figures and examples:

FIG. 1 is a system connection block diagram of the present invention;

FIG. 2 is a schematic diagram of the present invention;

FIG. 3 is a wiring diagram of an STM32 chip;

FIG. 4 is a wiring diagram of EPM7128 CPLD logic unit.

Detailed Description

The preferred scheme is as shown in fig. 1, a shore bridge CCTV time service system comprises a UBLOX module, a main control module and a CPLD logic unit; the UBLOX module is used for acquiring time information by using a GPS signal and then sending the time information to the main control module; the main control module is electrically connected with the CPLD logic unit and is used for realizing liquid crystal display and simultaneously sending the time information to the hard disk video recorder of the CCTV system through a network port or a 485 interface. The time of the hard disk video recorder is accurate, and the video is convenient to call later. The CPLD logic unit is provided with an optical fiber interface for connecting a network server.

The UBLOX module is called a U-blox chip and is a GPS positioning chip developed by Switzerland U-blox company, and the UBLOX module is mainly used for acquiring GPS time information in the technical scheme.

A temperature compensation crystal oscillator is arranged in the CPLD logic unit and used for improving the time service precision. All electronic components adopt a lead-free process, and a software part needs to be additionally provided with redundancy. The temperature compensation crystal oscillator adopts a 50MHz patch crystal oscillator.

The main control module is an STM32 main control chip. The controller is a 32-bit microcontroller of an ARM Cortex-M kernel, and has the basic models of STM32F101R6, STM32F101C8, STM32F101R8, STM32F101V8, STM32F101RB, STM32F101VB and the like. Preferably, the STM32 master control chip has a memory size of 64 Kb. Fig. 3 shows a wiring diagram of one chip of STM 32.

The CPLD is a programmable logic device, is a device developed from PAL and GAL devices, is relatively large in scale and complex in structure, and belongs to the field of large-scale integrated circuits. The digital integrated circuit is a digital integrated circuit which is used by a user to construct logic functions according to respective needs. The basic design method is to generate corresponding target files by means of an integrated development software platform and methods such as schematic diagrams, hardware description languages and the like, and to transmit codes to a target chip through a download cable (programming in the system) so as to realize the designed digital system. The specific model can be Altera EPM7128S (PLCC84), as shown in FIG. 4, which is a wiring diagram of a processing unit of the model.

The working principle of the whole device is as follows:

as shown in fig. 2, a radio frequency module is included in the UBLOX module, and the CPLD logic unit includes a frequency divider, a clock taming module, and a clock selecting module. The radio frequency module receives GPS time signals, the GPS time signals are processed through baseband signals, time state information (namely GPS _1 PPS) is transmitted to an STM32 main control chip, the STM32 main control chip collects and obtains an optimal pulse per second signal U1PPS, and the U1PPS is transmitted to a clock selection module in the CPLD logic unit. The temperature compensation crystal oscillator 50MHz outputs to the frequency divider to obtain OCXO _1Hz clock signal, the phase difference between the OCXO _1Hz clock signal and the second pulse signal U1PPS is compared, the difference between the OCXO _1Hz clock signal and the second pulse signal U1PPS is gradually reduced through the voltage-controlled tuning effect of the control signal on the temperature compensation crystal oscillator, and meanwhile, the rising edges of the second pulse signal U1PPS and the OCXO _1Hz clock signal are aligned finally through continuous calibration and correction in the closed-loop control process, so that the purpose of time synchronization is realized. And the CPLD logic unit transmits the verified pulse signals to an STM32 main control chip for amplification, and finally, the pulse signals are displayed by a liquid crystal screen.

Claims

1. A bank bridge CCTV time service system which characterized in that: the system comprises a UBLOX module, a main control module and a CPLD logic unit; the UBLOX module is electrically connected with the main control module, the main control module is electrically connected with the CPLD logic unit, and the CPLD logic unit is electrically connected with the temperature compensation crystal oscillator;

2. The shore bridge CCTV time service system according to claim 1, wherein: the frequency of the temperature compensation crystal oscillator is 50MHz, and the temperature compensation crystal oscillator is used for improving the time service precision.

3. The shore bridge CCTV time service system according to claim 1, wherein: the main control module is an STM32 main control chip.

4. The shore bridge CCTV time service system according to claim 1, wherein: the memory size of the STM32 master chip is 64 Kb.