RTSI 7 as reference clock source - do I need to buy another cable?

[Penny]

Hi everyone,

I am fiddling around with our new PCI-5114 digitizer and will eventually need to phase lock it to an external sine wave from our Agilent signal analyzer.  In the meantime, prior to doing that, I am trying some initial tests on the PCI-5114:  I would like to just lock the 250 MHz sample clock to the onboard 10 MHz RTSI_7 reference.  So far some things look reasonable.  I specified in NI-Scope.NET 2.0

scopeSession.Timing.ReferenceClocksource = "VAL_RTSI_7";

Then while running the code outputs these checks:

reference clock source is VAL_RTSI_CLOCK

reference clock rate is 10000000

sample clock timebase source is VAL_NO_SOURCE

and then it crashes with this message:  "PLL could not phase-lock to the external reference clock.  Make sure your reference clock is connected and that it is within the jitter and voltage specificiations.  also, make sure the reference clock rate is correctly specified."

My question is:  Do I need to export the RTSI signal to the front panel and then physically cable it to the CLK IN connector on the front panel?  Or can I somehow make the card do all of this for me via software?  If I need another cable to get this working then I will order it asap.

Thanks very much,

Penny

[Nathan-P]

Penny,

Congrats on the new PCI-5114 digitizer!  There are a couple of things that you are missing, that should help with this test.  

1. "VAL_RTSI_7" is not a valid string for the ReferenceClockSource.  The valid values are: "VAL_NO_SOURCE", "VAL_RTSI_CLOCK", "VAL_PFI_1", "VAL_PFI_2", "VAL_PXI_CLOCK", "VAL_EXTERNAL", and "VAL_CLK_IN".
   So, you probably want "VAL_RTSI_CLOCK"
   
   
2. By default, the RTSI_CLOCK line is just an input, and if I'm not mistaken, you can route the reference clock internally to the RTSI 7, and then specify RTSI 7 as your Reference Clock Source.  You can use NationalInstruments.ModularInstruments.NIScope.ScopeExportedSignals.ReferenceClockOutputTerminal, to specify where to export the reference clock.  You will want to use "NationalInstruments.ModularInstruments.NIScope.ScopeOutputClockSource.RtsiClock" for that fuction.

With both of these in place, it should work as you described, but I'm not 100% sure since I have not tested it on any hardware.

-Nathan

[Penny]

Hi Nathan,

Thanks as usual for the great suggestions.  I gave them a try, like this:

scopeSession.Timing.ReferenceClocksource = "VAL_RTSI_CLOCK";

scopeSession.Exported Signals.ReferenceClockOutputTerminal = ScopeOutputClockSource.RtsiClock;

Then I queried with some MessageBoxes and found that

1.  reference clock source is VAL_RTSI_CLOCK

2.  reference clock rate is 10000000

3.  sample clock timebase source is VAL_NO_SOURCE

4.  lock status is False.

Then the code crashes with this error:  "ModularInstruments.NIScope:  Specified route cannot be satisfied, because the hardware does not support it.

Source Device:  Dev1

Source Terminal:  Reference Clock

Destination Device:  Dev1

Destination Terminal:  PXI_Trig7

Status Code:  -89136

Error code:  -1074107505

I am a little concerned about the above hardware error that references the PXI_Trig7 terminal.  The syntax sounds more like a PXI message than a PCI one.

Should there be a way to run the PCI-5114 in the PLL mode as a standalone unit?  Or should we just move on for now to the other tests?

Thanks again,

Penny

[Penny]

Hi Nathan,

I think we actually are all set here.  I sent in a 10 MHz external reference to the CLK IN, and now we are locked.  Since this is what we were aiming for in the first place, I think we will just continue and not worry about the standalone PLL mode for the moment.  Again, many thanks for the timely and helpful advice! 

Best regards,

Penny