SWSYNC, Where does the time originate for the cRIO synchronization, the PC clock?

[rgodwin]

I have installed the beta software from

http://zone.ni.com/devzone/cda/tut/p/id/8278

to test the synchronization of clocks on cRIO devices. Where does the software that resides on the cRIO get its time from?  I understand that the IEEE 1588 synchronization is a master/slave setup.  Does that mean that the PC is the master and the cRIO the slave? 

[George_P_Burdell]

Synchronization for this Software Synchronization Beta Program is done with IEEE 1588.  This is a Precision Time Protocol (PTP) and follows a master/slave paradigm.  The master/slave decision making process follows an algorithm called Best Master Clock (BMC).  This can change if the algorithm determines one of the slaves to have a better master clock, hence, it becomes the new 'Grandmaster.'  The 'Grandmaster' is the timing that will be used to synchronize the cRIO's clock or the cRIO may be the 'Grandmaster' and synchronize the PC's clock (using the PCI-1588).  Therefore it depends on your setup and the result of the BMC algorithm. 

Please also take a look at the link below.  It explains the ins-and-outs of IEEE 1588 PTP synchronization.  It may provide some other useful information for your application.

Introduction to Distributed Clock Synchronization and the IEEE 1588 Precision Time Protocol:
http://zone.ni.com/devzone/cda/tut/p/id/2822