synchronization PXI-6115 and PXI-5411

[DeWit]

Hi,

I have trouble synchronizing a PXI-6115 board with a PXI-5411 board.

I tried to route the FREQ-OUT signal of the PXI-6115 to the RTSI-bus using the RTSI Control.vi and use it as an external clock source for the PXI-5411. But at the RTSI Control.vi I got the message: deviceSupportError.

Subsequently, I routed the board clock of the PXI-6115 to the RTSI-clock bus line using Route Signal.vi. Then I configured the PXI-5411 to use the RTSI-clock bus line as a reference using the Ref Clk Source.vi. No errors this time, but still no synchronization.

I tested the synchronization by generating a square wave (1000 ones 1000 zeros) with the PXI-5411 and sampling the generated wave with the PXI-6115. The number of sampled ones an
d zeros is not always the same.

Thanks,

DeWit

[DeWit]

I think the synchronization is not the problem. I synchronized the boards using the 10 MHz backplane clock. This should work.

However, the sample rate of the PXI-6115 is 20MHz/3 = 6,666,666.50 Hz, the frequency of the square wave is 1000 Hz. These are not multiples, so sometimes there is a sample less.

The sample rate should be at least 6 MHz, unfortunately this is not a dividend of the PXI-6115 board clock.
Is it possible with the PXI-6115 or the PXI-5411 to route not the board clock timebase, but the actual sample rate timebase (so the 6,666,666.50 Hz signal in case of the PXI-6115) to the RTSI-bus to use it as an external clock for another board?

Or does the PXI-6115 have some sort of high resolution clock mode?

Thanks again,

DeWit

[Spencer S.]

DeWit,

It sounds to me like you want to route the actual convert clock from the 6115 to the 5411. To do this, use Route Signal.vi to route the "AI convert" signal to a RTSI line.

Good luck with your application.

Spencer S.

[DeWit]

Thanks for your answer.

I decided to adapt the entire system to the sample frequency of the PXI-6115.
So the board clocks are coupled via the 10 MHz backplane clock and the sample frequency of both boards is 20 MHz/3. It seems to work fine now.

Thanks,

DeWit