Max. Words function?

Thank you for this great plugin. I use it to read out various websites via RSS (with their approval) and to display the latest content on our monitor. Unfortunately, the content is often too long. Because everything is automated, i cannot create a text excerpt. Now I’m looking for a way to display only the first X words in the slide. Actually i think, it can’t be that difficult, does anyone know how to do it? Many thanks in advance.