Is PCIe a requirement? FTDI (assuming you get them from reliable sources) produce very reliable USB to RS232 cables. They also have TTL and LVTTL versions.
LAN - Did you set up the R&S IP address? Do you get Ping replies?
USB - Did you install the USB drivers from R&S? does the device appear in Windows device manager?
What is the model of the SA?
When writing arrays directly to Excel, there is a time limit for Excel to write the array to the selected range. If that limit is exceeded, you will get an error.
The .NET API provides a more detailed error than the ActiveX API.
This is the closest thing to a pinout I could find for the PXIe-2525. You will have to check connectivity between the 160 pin connector and the 50 position terminals.
NI MAX 2020 doesn't list this board.
GUID-04647FDC-4447-45DA-9BB2-4E10EA993437-a5.svg
You will have to convert the OpenCV MAT to LV picture. The MAT object has a ToBitmap method, which can generate a LV compatible bitmap.
I attached a VI that uses the EmguCV .NET wrapper.