You can use IF condition to ignore the zero values from that Attribute and perform the standard deviation calculation. Below is the sample expression,
If 'Attribute1' <> 0 then StDev('Attribute1','*','*-1h') else "Bad Input"
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The method you described above did not work for this case, but, I did figure out a way around it. With the filtered expressions, instead of setting a filtered value to zero, I set the value to 'BAD', which seems to be similar to the 'nooutput()' expression in analyses. Then in the analysis, I can simply do StDev('Attribute1','*','*-1d').
The formula is something along these lines
A=Power;B=|Power|Min;C=|Power|Max;D=SAG Mill Feed Rate Filter;[if (A>B and A<C and D>100) then A else BAD]