PXI-6682H

[bahec666]

Hello. I have PXI-6682H with chasis PXIe1082. I'd like to set time of my timing module from NTP server and get time with resolution of 1 usec. Also i would like to synchronize my ni5761 module and get data with timestamp with resolution of 1 usec. But the cycle executed with the step of 10 msec. How i can reduce this time? And how i can get time from NTP server and set this time to PXI-6682H?

[MCOTO]

Hi,

Please refer to the Start 1588 and Wait for Quality example navigating to the menu Help >> Find Examples >> Hardware Input and Output >> Timing and Synchronization >> Time-Based >> Start 1588 and Wait for Quality. Please also refer to the advanced help of the niSync Start 1588 VI.

Regards,

MCOTO

[Alisha_P]

Hi bahec666,

I'm a little confused by your question. You mention that you'd like to set the time of the 6682H from an NTP server. However, your code shows that you are doing 1588 synchronization. 

If you're hoping to use an NTP server, then you can normally only expect synchronization within tens of milliseconds. Also the 6682H does not support NTP synchronization. See section 4 of the manual for what synchronization options there are: http://www.ni.com/pdf/manuals/372292b.pdf

If you're hoping to synchronize using 1588, as your code shows, then once you have set 1588 as the time reference, you need to wait for synchronization to complete by monitoring the "Offset from Time Reference" to make sure the card is synchronized to your spec. After that, the clock should maintain synchronization and should not affect your loop rate (it certainly shouldn't take 10ms to get a timestamp, for example). It's hard to tell from a picture of your code what is slowing down the loop, but ascertaining synchronization is where you would want to start.

Alisha Pulsipher

NI R&D

[Alisha_P · Accepted solution]

Here's an example of how to monitor synchronization. You should be able to set what values you desire for Offset Threshold and Synchronization Settling Time (how long you want it to maintain the Offset Threshold before declaring that synchronization has been reached). Place it after setting the time reference.