The Design And Implementation Of Time Unified System In The Multi-Level Measurement And Control System

In the networked multi-level measurement and control system,workstations and instruments are distributed in different locations and can be used as network nodes.According to the level of the workstation,the workstation has measurement and control requirements for its subordinate workstations and the instruments it owns.In order to achieve better coordination between workstations at different levels,the workstation and the instruments it owns,a unified time is required for coordinated control.The purpose of the time unified system in the multi-level measurement and control system is to achieve uniformity of time and consistency of data for workstations at different levels distributed in different locations.This thesis focuses on solving the problem of inconsistency in the workstations at different levels and realizes a system that unifies time between multi-level workstations.The difficulty of time uniformity is the accuracy of time and frequency.This thesis introduces time standards,frequency standards and timing methods of the time unified system.Through comparison and analysis,this thesis selects Coordinated Universal Time as the time standard,selects the RTC of the computer as the frequency standard,and selects network timing as the timing method.This thesis uses the client/server structure.The client only receives the time synchronization command,which is provided to the temporary node of the workstation for use.The server can send and receive time synchronization command,which is provided to the fixed node of the workstation for use.The main functional modules of the system include the data processing module,the system’s parameter configuration module,the time synchronization module and the status monitoring module.The time synchronization module calculates the time difference between operating systems using the four timevalues involved in the principle of NTP.These four values are the local time of the requester when the request message leaves the time requester,the local time of the responder when the request message arrives at the time responder,the local time of the responder when the response message leaves the time responder,and the local time of the requester when the response message arrives at the time requester.The synchronization time value of the time unified system is calculated by using the time difference between the time unified system and the operating system in which it operates and the time difference between the operating systems.The time unified system in the multi-level measurement and control system has realized time uniformity and data consistency in the local area network.The system has also solved the problem that the time of workstation nodes at different levels is not uniform when the superior sends the measurement and control command,so that each node can better cooperate to complete the task.This system can be used in any scenario where there is a subordinate relationship and there is a requirement for uniform time.