Czechmarty,
This is an easy one to miss, I actually made this mistake a little less than a week ago before figuring out my problem. The problem is that you cannot use sample clock timing with a CI Frequency task. There are 3 solutions to this problem:
- Get one of our new X Series Cards that have a sample clock line on each of their 4 counters
- Perform a count edges and do a frequency calculation in software (only for low frequencies) like in this example.
- Last but certainly not least (the easiest fix) is to switch your timing type from Sample Clock to Implicit this won't allow you to "sync" your counters but I really doubt this is a problem.
Sincerely,
Jason Daming
Applications Engineer
National Instruments
http://www.ni.com/support
