Thread Subject: Embedded MATLAB function error

Dear Freinds,

This code gives error called the cut-off frequency should be under 0.1 .
when replaced 0.9 with 6.366. The reason I have mentioned 6.366 because I have tried using butter-worth low pass filter with pass band edge frequency of 40 rad/sec and it works good.

function output_data=butter_filt(input_data)
%#eml
[b,a]=butter(6,0.9);
output_data=filter(b,a,input_data);

how can I filter a 230V 50Hz frequency using the above low-pass filter code?

with best regards,
sandhi