A Solution On Precision Master Clock Server

In industrial control system and grid system, precise time synchronization is crucial to the stability and efficiency of whole system. Generally, every client in those systems has their own local timer and those timers have their own local crystal oscillator. Due to different environmental parameters and uniqueness of each crystal, there is no guarantee that after set in the same rate all these timers can stay in synchronization. And this is why we urge the need of a simple continuous time synchronization protocol. There used to be IRIG-B serial protocol which being widely used in industry. But this protocol needs a dedicated medium to transmit synchronization information. The new coming IEEE1588in year2002was designed as improvement of the old IRIG-B serial protocol and the even older NTP protocol. Like NTP, IEEE1588protocol is based on the OSI protocol stack. It provides an relatively easy way to synchronize over different networks and does not need an dedicated medium to transmit synchronization information, instead, it uses the popular ether network or can even run upon higher protocol like UDP. IEEE1588is a relatively simple protocol thus bandwidth consumption, processing power and setups are low. With a dedicated hardware, which could be an ASIC or FPGA implementation of the entire protocol or a network adapter chip implemented the functionality of the lower stack of IEEE1588, the whole system can achieve μ second level or higher precision. Thus, IEEE1588has been used in many fields for time synchronization mechanism.This essay was talked about a master clock implementation of IEEE1588protocol. Our clock got time source from GPS and communicate with other slave client via Ethernet. This master clock used a dedicated network adapter chip DP83640 which interact with the software part of the rest protocol running under Linux operating system. Time stamps were read directly from the adapter, so we can keep the precision higher than μ seconds level. This essay talked about main character and core algorithm of IEEE1588protocol, then analyzed some parts of the protocol and described how to implement them in an applied way. At the mean time we would talk about the decision-making of choice of modules of our system as we focus on the application on grid power system.