GPS Timing Module 6683H and 6674T

[gmacca01]

Hello,

I have a 6683H  and a 6674T. 

Currently don't have the 6683H connect to GPS, but I was wondering how I could access the 10 MHz on the CLKOUT front panel port via the free runnign TCXO? 

I can't currently find any VI's or help that actually setup the 6683H to startup or output the 10 MHz on the CLKOUT port. I have the correct drivers and can access the test panel on NI MAX, but I'm definitely missing something. Any tutorials or help regarding these modules would help. 

Thanks for your help!

-Gmac

[TylerK]

Hi Gmac,

To get started, take a look at the Route Clock.vi example in LabVIEW. You can find the example in NI Example Finder under Hardware Input and Output»Timing and Synchronization»Signal-based.  Also, both the PXI-6683H and PXIe-6674T use the NI-Sync driver.  In LabVIEW, You will find the NI-Sync palette under Functions»Measurement I/O»NI-Sync.

Regards,

-Tyler

[gmacca01]

Dear Tyler,

I have such drivers and I've tried this. I tried many options for the source terminals and the destination termail (CLKOUT) for the GPS device slot, but still nothing out of CLKOUT. Do you know if these can free run with a GPS input and also without the 6674T module? that's really what I'm interested in experimenting with right now. Any other thoughts would be nice. Thanks so much!

Best,

-Gmac

[Nick@NI]

Gmac,

I actually just happen to have a 6683H setup with a digitizer next to it.

I used Route Clock.vi and cabled CLKOUT to Ch0 of the digitizer.

I've attached a screenshot of this. I assume you've tried this setting already? Try going into MAX and resetting the device first before trying Route Clock.vi again. You might have established some routes that need to be disconnected first.

To answer your question, yes 6683H can run independently without a GPS input and without 6674T.

Regards,

Nick

[gmacca01]

Dear Nick,

Thanks, it appears my one GPS module has an issue as it doesn't output the 10MHz, but another module worked just fine. It appears to be a hardware issue. 

I have an additional question now. 

Say I have at timing module (6674T) and a gps module (6683H) on two separate chassis. Is there a way to train either the TCXO (GPS) or OCXO (timing module) from one chassis on the other and then disconnect and let them free run without GPS? 

right now it's obvious that there is some frequency offset between both of my 10 MHz sources and I'd like to get them aligned as best as possible. Thanks for your help and advisement!

Best,

-Gmac

[Nick@NI]

Hi Gmac,

Can you clarify your question?

- Are you trying to have no physical connection between the two chassis? (one chasis with the 6683H, the other with 6674T)

If there is no physical connection between them, the clocks will drift.

- Or, are you trying to discipline the 6683H TCXO to GPS, and then you want to disconnect the GPS antenna. i.e. let the board free run and have the second chassis share the same clock?

In your use case, physical cabling is required to sychronize two seperate chassis. The 10MHz reference from either the 6683H or the 6674T needs to be cabled to the other so that there's a single reference for both chasis to be synchronized.

If you don't want physical cabling, you will need a 6683H in each chassis to discipline their 10MHz TCXO to GPS, and then set both boards to overdrive PXICLK10 in the backplane.

Regards,

Nick

[AlejandroZepeda]

Hi.

To add to that. there is one other possibility: if you have the PXI-6683H and PXIe-6674T in different chassis, but controlled by the same computer (via MXI), then you could output the PXIe-6674T's OCXO via its CLKOUT terminal and import it into the PXI-6683H's chassis to replace that chassis's PXI_CLK10. With that setup you could then run the 2-board clock disciplining VI and it should work.  It would probably be easier to have both boards in the same chassis and just output the disciplined 10MHz clock to the second chassis, but if you need them to be in separate chassis it can be done as described.

Hope this helps.

Regards,

Alejandro