LVDS loopback using NI 6589 - LabView Error 61046

[jano1337]

Hello, 

I am trying to perform a BER measurement on LVDS line using NI 6589 module with PXIe-7972R. In order to do So I am trying to generate a LVDS signal on one of LVDS channels and acquire the same signal on the other channel. I'm using Serdes Channel CLIP Connector.

I am using "NI 6589 Continuous Generation - Export Clock" example as a base for the project.

In the target (FPGA) VI a have two timed loops for generation and acqisition clocked by "Gen_Regional_Clock" and "Acq_Regional_Clock" accordingly. 

In the Host VI  I'm setting the "Gen_IO_Clock_Source" to the "Adapter Module onboard Clock". And now: I am also exporting that clock to the DDC connector pins in order to connect that clock to the STROBE pins, I am doing so because i am choosing Acq_IO_Clock_Source as "Strobe bypass". And this is where I am getting the -61046 error. 

The full error message:

"Error -61046 occurred at Read/Write Control in Gen_and_Aquire_Serdes_ch(HOST).vi"

"Possible reason(s):

LabVIEW FPGA: An error was detected in the communication between the host computer and the FPGA target.

If you are using any external clocks, make sure they are connected and within the supported specifications. Also, verify that the rate of any external clocks match the specified clock rates. If you are generating your clocks internally, please contact National Instruments Technical Support."

When i instead choose  "Adapter Module onboard Clock" as a Acq_IO_Source I am able to run the VIs and even acquire generated data, though it is out of sync.

I marked on the screenshot where exacly am i getting the error. Am I doing something wrong there or in the wrong order maybe? 

The clock is generated succesfuly on the CLK_OUT pins - checked on the osciloscope. I am connecting CLK_OUT pins to STROBE pins physicaly of course, so i'm geussing the problem is within the software.

I am uploading screenshots of my host and target VIs as well as the VIs themselves. If anyone had similar problem or have idea what am i doing wrong, please provide me some help.

[jano1337 · Accepted solution]

I have found similar topic:

https://forums.ni.com/t5/LabVIEW/SERDES-Clip-Using-Regional-Clocks/td-p/3795262

I moved the controls out of the loop and it seems to be working. I don't have enought knowledge to explain this behavior.