Hi Ross,
I'm not really sure what you're trying to do with this statement:
fn-Substring({ItemProperty:Summary_x0020_Description},0,255,
{ItemProperty:Cycle_x0020_Time_x0020_Improveme},0,255{ItemProperty:Quality_x0020_Improvement},0,255)
It looks like you are trying to pass 9 parameters to the fn-SubString and that won't work.
Are you trying to get the substring of 3 separate fields and then concatenate them? If that is it, you'd be looking at something like this :
fn-Substring({ItemProperty:Summary_x0020_Description},0,255)fn-Substring({{ItemProperty:Cycle_x0020_Time_x0020_Improveme},0,255)fn-Substring({{ItemProperty:Quality_x0020_Improvement},0,255)
You can test this out by opening a Build String action, clicking on the Run Now in the ribbon and trying something like this:
fn-SubString(abcde,0,3)fn-SubString(fghij,0,3)fn-SubString(klmno,0,3)
You should see a result of:
abcfghklm