03-01-2013 12:22 PM
Hello,
We are trying to use PXI-5600 Downconverter with PXI-5142 Digitizer; however, there seems to be a problem with the external reference clock. This message seems to have occured to others in the past as well with different devices.
The cabling is done well, and everything worked for one Test Panel. However, now we keep on received an error message "PLL could not phase-lock to the external reference clock", and we are not sure how to know whether the reference clock is "... within the jitter and voltage specifications" and how to specify the correct "the reference clock rate".
Thanks for your help,
Ignas
03-04-2013 03:54 PM
Are you using an external reference clock?
If so, note that the 5600 specifications indicate a locking range of 0.5 ppm. Using an external reference that is off by more than 0.5 ppm would be my first guess as to why it is not locking. For example, the 10 MHz reference that the chassis provides is usally off by much more than 0.5 ppm (so unless you are locking the chassis to an external reference, the 5600 typically won't be able to lock to PXI_Clk10).
03-04-2013 07:39 PM
Hello, Ignas!
Mbb25 makes an excellent point. Please let us know!
Best,
Will H | Applications Engineering | National Instruments | SR# 1979261
03-04-2013 08:30 PM
Hi,
Thank you for the reply, I will keep that in mind as a solution for the future issues. However, eventually what we had to do is to replace one of the cables. I almost wish that it was something more complicated 😄 since I definitely saw everything running earlier.
Anyway, I appreciate your help, and will probably be back before long with more questions.
Best regards,
Ignas
03-05-2013 10:06 AM
We're happy to help, Ignas - glad you hunted down the pesky cable. Have a good one!
Best,
Will H | Applications Engineering | National Instruments