sample frequency in digital IIR filter

[cig438]

I have a waveform (1D array of SGL) that I need to lowpass filter. When I use the Butterworth VI, I can set the sample frequency with which to sample & vary the cutoff freuqency & observe the low-pass filtering results.
When I use the digital IIR filter VI, it gves me the error :

Analysis:  The following conditions must be met:  0 < f_low <= f_high <= fs/2.

How does it know what the sampling frequency is ?
IS there a setting in the IIR filter specifications cluster that will help ?

ak

[Chris_Cilino]

cig438,

Can you post a small section of your code that demonstrates the problem?

Chris C