Interface monitor

sorry for my poor english

I have a interface,sometimes the interface is bad ,then  point  will pull straight line in PB,I can't find interface problems in a timely manner.then I use the PE to monitor  interface,just like

(BadVal(TagVal('tag1', '*')) AND  BadVal(TagVal('tag1', '*-20m'))AND TagVal('tag1', '*-20m')-TagVal('tag1', '*'))

or (BadVal(TagVal('tag2', '*')) AND  BadVal(TagVal('tag2', '*-20m'))AND TagVal('tag2', '*-20m')-TagVal('tag2', '*'))

...

or(BadVal(TagVal('tagn', '*')) AND  BadVal(TagVal('tagn', '*-20m'))AND TagVal('tagn', '*-20m')-TagVal('tagn', '*'))

=0

I use a few points,These points must be used and change very quickly,if 0 interface is ok,and if 1 interface is bad ,then I will set the SMS notification