Help for Bollingar Band Scanner.

Guys, I am trying to write a scanner to find stocks that have reached lower bollingar band with setting of bbandbot(C,200,2) on a 5 min chart.

below is the code That I have written which I think should work but for some reason when I scan nothing comes up in scanner, I'll appreciate if any body could guide me where I am going wrong.

_section_begin("Bollingar band scanner 5min")

timeframeset(in5minute);
a = (L<= (bbandbot(c,200,2))) AND ref(L,-1)>(ref(Bbandbot(c,200,2),-1));
timeframerestore();

filter = a;

addcolumn(a,"Bottom hit",colorblack,1.2);





that's it and no error is shown while saving but on scanning nothing comes up.