Scaling pixels to meters, convert to PNG

Hello,

I'm trying to figure out how to scale a drawing to 20 pixels per meter, then convert the drawing to a PNG image (with no antialiasing). I've been trying to scale and convert to PNG through Print to File, but the PNG is always only a few pixels on each axis (the layout I'm trying to print is 200k sqft). Anyone have experience with this kind of thing? Thanks