How would I go about triggering an event when a chop reaches a certain value.
say when ever a chop reaches 1 then an event occurs (eg the background changes colour)
many thanks 
As always in touch, there are tons of ways to approach it. Given your example, try this:
your channel > trigger CHOP > count CHOP > export to switch TOP index parameter
you could also point a text DAT to the trigger CHOP and have it execute a script on “offtoon” …