“Donchian” is not a ProScreener instruction, you have to build yourself the upper and lower Donchian channel lines. Comparing your “body” variable (which is a difference of 2 prices in points) with the Donchian channels in price value, lead to nothing 🙂
..and SCREENER conditions must be in brackets, not in parenthesis.
First below or first above is not possible, because if you are above you are the new Donchian upper line and vice-versa if you are below, so we are comparing with the previous period of each of the channel line.