to what sink should i connect to observe the output of digital filter.

Hi, I am new to simulink.Inorder to observe the output of digital filter(lowpass) ,to what sink should i connect my filter.i tried connecting it to vector scope.But then error displays as "Error reported by S-function 'sdspsigattrib' in '/Digital Filter Design1/Check Signal Attributes/Check Signal Attributes': Input must be floating-point.my input to the filter is an analog to digital converted signal.Please help me sort out this problem.. thank you Amrutha